Charge protection circuit, driving method, chip, package structure, and electronic device

Abstract

The embodiments of the present application relate to the field of power supply system technology, and provide a charging protection circuit, a driving method, a chip, a package structure, and an electronic device to provide a charging protection circuit with a stable bidirectional protection effect. The charging protection circuit includes a first switching transistor and a pull-up circuit. For example, the first switching transistor is a bidirectional HEMT device and includes a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The first drain electrode is configured to receive a signal from the second drain electrode, the second drain electrode is configured to receive a signal from the first drain electrode, and the first gate electrode is configured to control the first switching transistor to be turned on or off. The pull-up circuit is configured to adjust the potential of the substrate electrode to a high potential when the first switching transistor is turned on, to ensure that the turn-on characteristics of the first switching transistor are not affected.

Description

Technical Field

[0001] This application claims the priority of Chinese Patent Application No. 202110867195.X, titled "CHARGING PROTECTION CIRCUIT, DRIVING METHOD, CHIP, PACKAGE STRUCTURE, AND ELECTRONIC DEVICE", filed with the State Intellectual Property Office of China on July 29, 2021, the entire content of which is incorporated herein by reference.

[0002] This application relates to the field of power supply system technologies, and in particular, to a charging protection circuit, a driving method, a chip, a package structure, and an electronic device.

Background Art

[0003] With the continuous development of electronic technologies, the charging technologies of electronic devices are also continuously innovated. A charging circuit is used as an example. To meet different requirements, existing charging circuits can implement both wired power charging and wireless charging, and support both unidirectional charging and bidirectional charging. Therefore, the charging protection circuit in the charging circuit needs to be a power device with a bidirectional blocking function to implement bidirectional protection (over voltage protection, OVP) in two different directions for the device coupled to the load end or the device coupled to the power supply end.

[0004] For example, during wired charging, when the voltage at the power supply end is unstable, overvoltage protection can be implemented for the device coupled to the load end. During wireless charging, reverse current flow on the port coupled to the power supply end is prevented. Alternatively, for example, during forward charging, when the voltage at the power supply end is unstable, overvoltage protection can be implemented for the device coupled to the load end. During reverse discharge, when the voltage at the load end is relatively high, overvoltage protection can be implemented for the device coupled to the power supply end.

[0005] Therefore, how to implement stable bidirectional protection for devices connected to the load terminal or devices connected to the power supply terminal during the charging process becomes an important issue for those skilled in the art to study.

Summary of the Invention

Means for Solving the Problems

[0006] Embodiments of the present application provide a charging protection circuit, a driving method, a chip, a package structure, and an electronic device to provide a charging protection circuit with a stable bidirectional protection effect.

[0007] To achieve the above object, the following technical solutions are used in the present application.

[0008] According to a first aspect of an embodiment of the present application, a charging protection circuit is provided. The charging protection circuit herein can be understood as a bidirectional protection circuit. When applied to the upper-end charging circuit, the charging protection circuit can implement overvoltage protection for devices connected to the power supply terminal and the load terminal of the charging circuit. The charging protection circuit includes a first switching transistor and a pull-up circuit. The first switching transistor includes a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The first gate electrode is configured to control the first switching transistor to be turned on or off. The first drain electrode is configured to receive a signal from the second drain electrode, and the second drain electrode is configured to receive a signal from the first drain electrode. In other words, the first switching transistor is a bidirectional switching transistor. The pull-up circuit is coupled to the first gate electrode and the substrate electrode and is configured to adjust the potential of the substrate electrode to a threshold value (for example, the threshold value is any potential between half of the potential of the first drain electrode and the potential of the first gate electrode) to ensure the turn-on characteristic of the first switching transistor when the first switching transistor is turned on.

[0009] When the first switching transistor is turned on, if the potential of the substrate electrode is lower than that of the first drain electrode and the second drain electrode, the on-resistance of the first switching transistor increases due to the back-gate effect. As a result, the performance of the first switching transistor deteriorates. Therefore, according to the charge protection circuit provided in this embodiment of the present application, the pull-up circuit is disposed between the first gate electrode and the substrate electrode. When the first switching transistor is turned on, the voltage bias between the first gate electrode and the substrate electrode becomes the desired potential, and the potential of the substrate electrode is adjusted to a threshold value (for example, equal to or approximately equal to the potentials of the first drain electrode and the second drain electrode). This can avoid the phenomenon that the turn-on resistance increases due to the back-gate effect caused by the charge accumulation of the substrate electrode, and ensure that the turn-on characteristics of the first switching transistor are not affected. In addition, the first switching transistor in this example is a single-gate bidirectional conduction device and has a small cell size. The single-gate bidirectional conduction device has a smaller characteristic resistance compared with the dual-gate bidirectional conduction device.

[0010] In some embodiments, the charge protection circuit further includes a pull-down circuit. The pull-down circuit is coupled to the substrate electrode and the fixed signal terminal, and is configured to adjust the potential of the substrate electrode to the potential of the fixed signal terminal or the potential between the first gate electrode and the fixed signal terminal when the first switching transistor is turned off. That is, the pull-down circuit adjusts the potential of the substrate electrode to a low potential when the first switching transistor is turned off. The potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode and the second drain electrode when the first switching transistor is turned off.

[0011] When the first switching transistor is turned off, if the potential of the substrate electrode is high with respect to the first drain electrode and the second drain electrode, for example, when VSub - VD2 > 0 V, the substrate electrode induces positive charges, which causes a narrower width of the depletion region in the channel. As a result, the first switching transistor is likely to have channel punch-through at a low voltage, and as a result, the breakdown voltage capability is insufficient. Therefore, according to the charging protection circuit provided in this embodiment of the present application, the pull-down circuit is arranged between the substrate electrode and the fixed signal terminal. On the other hand, when the first switching transistor is turned off, the voltage of the first gate electrode gradually decreases, and the potential of the substrate electrode decreases together with the potential of the first gate electrode. On the other hand, the pull-up circuit enables the first gate electrode to be almost open-circuited with respect to the substrate electrode, and the pull-down circuit enables the substrate electrode to be almost short-circuited with respect to the fixed signal terminal, so as to adjust the potential of the substrate electrode to be approximately equal to the potential of the fixed signal terminal (for example, the reference ground terminal) or the potential between the first gate electrode and the fixed signal terminal. As a result, the breakdown characteristics of the first switching transistor are not affected at all, and it is ensured that the breakdown voltage characteristics of the first switching transistor are not affected.

[0012] In some embodiments, the pull-up circuit includes a first resistor. The first end of the first resistor is coupled to the first gate electrode, and the second end of the first resistor is coupled to the substrate electrode. By using the voltage division principle of the resistor, when the first switching transistor is turned on, the voltage bias between the first gate electrode and the substrate electrode becomes the desired potential. The structure is simple, the implementation is easy, and the cost is low.

[0013] In some embodiments, the pull-up circuit includes a clamping diode. A first end of the clamping diode is coupled to the first gate electrode, and a second end of the clamping diode is coupled to the substrate electrode. By using the clamping voltage drop during turn-on of the clamping diode, when the first switching transistor is turned on, the voltage bias between the first gate electrode and the substrate electrode becomes the desired potential, which is easy to implement and has low cost.

[0014] In some embodiments, the first end of the clamping diode is the anode, and the second end of the clamping diode is the cathode. The clamping diode is a PN diode, a Schottky barrier diode, or an equivalent diode obtained by short-circuiting the source electrode and the gate electrode of a transistor.

[0015] In some embodiments, the first end of the clamping diode is the cathode, and the second end of the clamping diode is the anode, and the clamping diode is a Zener diode.

[0016] In some embodiments, the pull-up circuit includes a plurality of clamping diodes connected in series. In this way, the clamping voltage of the clamping diode may be adjusted by adjusting the structure of the clamping diode, or the clamping voltage of the clamping diode may be adjusted by adjusting the number of clamping diodes, meeting various application requirements.

[0017] In some embodiments, the pull-up circuit further includes a second switching transistor. The second gate electrode of the second switching transistor is coupled to the first gate electrode, the first electrode of the second switching transistor is coupled to the second end of the first resistor or the second end of the clamping diode, and the second electrode of the second switching transistor is coupled to the substrate electrode. The second switching transistor is disposed in the pull-up circuit and is turned off when the first switching transistor is turned off. In this case, when the second switching transistor is turned off, the impedance of the second switching transistor is much larger than the impedance of the pull-down circuit 23, and the potential of the substrate electrode can be adjusted to the potential of the fixed signal terminal (much lower than the lower potential of the first drain electrode and the second drain electrode). This can ensure that the breakdown characteristics and breakdown voltage characteristics of the first switching transistor are not affected.

[0018] In some embodiments, the pull-down circuit includes a second resistor. The first end of the second resistor is coupled to the substrate electrode, and the second end of the second resistor is coupled to the fixed signal terminal. Using the voltage division principle of the resistor, when the first switching transistor is turned off, the substrate electrode is substantially short-circuited to the fixed signal terminal. This structure is simple, easy to implement, and low in cost.

[0019] In some embodiments, the first switching transistor is a high electron mobility transistor. The high electron mobility transistor has a larger bandgap width, a higher breakdown electric field strength, and a higher electron saturation velocity.

[0020] In some embodiments, the first switching transistor is a metal oxide semiconductor transistor. The metal oxide semiconductor transistor has a simple structure.

[0021] In some embodiments, the second switching transistor is a high electron mobility transistor. The high electron mobility transistor has a larger bandgap width, a higher breakdown electric field strength, and a higher electron saturation velocity.

[0022] In some embodiments, the second switching transistor is a metal oxide semiconductor transistor. The metal oxide semiconductor transistor has a simple structure.

[0023] In some embodiments, the first switching transistor and the second switching transistor share the same substrate electrode. Thereby, the integration degree of the charge protection circuit can be improved.

[0024] In some embodiments, the first resistor is integrated on the substrate electrode. Thereby, the integration degree of the charge protection circuit can be improved.

[0025] In some embodiments, the second resistor is integrated on the substrate electrode. Thereby, the integration degree of the charge protection circuit can be improved.

[0026] According to a second aspect of the embodiments of the present application, a driving method of a charge protection circuit is provided. The charge protection circuit includes a first switching transistor and a pull-up circuit. The first switching transistor includes a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The pull-up circuit is coupled to the first gate electrode and the substrate electrode. The driving method of the charge protection circuit includes that the first switching transistor is turned on under the control of the first gate electrode, the first drain electrode receives a signal from the second drain electrode, or the second drain electrode receives a signal from the first drain electrode, and after the first switching transistor is turned on, the pull-up circuit adjusts the potential of the substrate electrode to a threshold value. The threshold value is any potential between half of the potential of the first drain electrode and the potential of the first gate electrode.

[0027] When the first switching transistor is turned on, if the potential of the substrate electrode is lower than that of the first drain electrode and the second drain electrode, the on-resistance of the first switching transistor increases due to the back-gate effect. As a result, the performance of the first switching transistor deteriorates. Therefore, according to the charge protection circuit provided in this embodiment of the present application, the pull-up circuit is disposed between the first gate electrode and the substrate electrode. When the first switching transistor is turned on, the potential of the substrate electrode is adjusted to a threshold value (for example, equal to or approximately equal to the potentials of the first drain electrode and the second drain electrode). This can avoid the phenomenon that the turn-on resistance increases due to the back-gate effect caused by the charge accumulation of the substrate electrode, and can ensure that the turn-on characteristics of the first switching transistor are not affected.

[0028] In some embodiments, the charge protection circuit further includes a pull-down circuit. The pull-down circuit is coupled to the substrate electrode and the fixed signal terminal. The driving method of the charge protection circuit further includes that when the first switching transistor is turned off under the control of the first gate electrode, after the first switching transistor is turned off, the pull-down circuit adjusts the potential of the substrate electrode to the potential of the fixed signal terminal or the potential between the first gate electrode and the fixed signal terminal. The potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode and the second drain electrode when the first switching transistor is turned off.

[0029] When the first switching transistor is turned off, if the potential of the substrate electrode is high with respect to the first drain electrode and the second drain electrode, for example, when VSub - VD2 > 0 V, the substrate electrode induces positive charges, which causes a narrower width of the depletion region in the channel. As a result, the first switching transistor is prone to channel punch-through at a low voltage, and as a result, the breakdown voltage capability is insufficient. Therefore, according to the charging protection circuit provided in this embodiment of the present application, the pull-down circuit is disposed between the substrate electrode and the fixed signal terminal. On the other hand, when the first switching transistor is turned off, the voltage of the first gate electrode gradually decreases, and the potential of the substrate electrode decreases together with the potential of the first gate electrode. On the other hand, the pull-up circuit enables the first gate electrode to be substantially an open circuit with respect to the substrate electrode, and the pull-down circuit enables the substrate electrode to be substantially short-circuited with respect to the fixed signal terminal, and adjusts the potential of the substrate electrode to be approximately equal to the potential of the fixed signal terminal (for example, the reference ground terminal) or the potential between the first gate electrode and the fixed signal terminal. As a result, the breakdown characteristics of the first switching transistor are not affected at all, and it is ensured that the breakdown voltage characteristics of the first switching transistor are not affected.

[0030] In some embodiments, the pull-up circuit includes a first resistor, and the pull-down circuit includes a second resistor. Adjusting the potential of the substrate electrode by the pull-up circuit to the threshold value means that the first gate electrode controls the first switching transistor to turn on (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn on), and the potential of the substrate electrode is adjusted to the threshold value by the voltage division effect of the first resistor and the second resistor. Adjusting the potential of the substrate electrode by the pull-down circuit to the potential between the first gate electrode and the fixed signal terminal means that the first gate electrode controls the first switching transistor to turn off (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn off), and the potential of the substrate electrode is adjusted to the potential between the first gate electrode and the fixed signal terminal by the voltage division effect of the first resistor and the second resistor.

[0031] In some embodiments, the pull-up circuit includes a first resistor and a second switching transistor, and the pull-down circuit includes a second resistor. Adjusting the potential of the substrate electrode by the pull-up circuit to the threshold value means that the first gate electrode controls the first switching transistor to turn on (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn on), the second gate electrode controls the second switching transistor to turn on, and the potential of the substrate electrode is adjusted to the threshold value by the voltage division effect of the first resistor and the second resistor. Adjusting the potential of the substrate electrode by the pull-down circuit to the potential of the fixed signal terminal means that the first gate electrode controls the first switching transistor to turn off (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn off), the second gate electrode controls the second switching transistor to turn off, and the potential of the substrate electrode is adjusted to the potential of the fixed signal terminal by the voltage division effect of the first resistor, the second switching transistor and the second resistor.

[0032] In some embodiments, the pull-up circuit includes a clamping diode, and the pull-down circuit includes a second resistor. The pull-up circuit adjusting the potential of the substrate electrode to the threshold value includes the first gate electrode controlling the first switching transistor to turn on (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn on), the clamping diode turning on, and the potential of the substrate electrode being adjusted to the threshold value. The pull-down circuit adjusting the potential of the substrate electrode to the potential between the first gate electrode and the fixed signal terminal includes the first gate electrode controlling the first switching transistor to turn off (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn off), and the potential of the substrate electrode being adjusted to the potential between the first gate electrode and the fixed signal terminal by the voltage dividing action of the clamping diode and the second resistor.

[0033] In some embodiments, the pull-up circuit includes a clamping diode and a second switching transistor, and the pull-down circuit includes a second resistor. The pull-up circuit adjusting the potential of the substrate electrode to the threshold value includes the first gate electrode controlling the first switching transistor to turn on (in this case, the potential of the first gate electrode is the potential for controlling the switching transistor to turn on), the second gate electrode controlling the second switching transistor to turn on, the clamping diode turning on, and the potential of the substrate electrode being adjusted to the threshold value. The pull-down circuit adjusting the potential of the substrate electrode to the potential of the fixed signal terminal includes the first gate electrode controlling the first switching transistor to turn off, the second gate electrode controlling the second switching transistor to turn off, and the potential of the substrate electrode being adjusted to the potential of the fixed signal terminal by the voltage dividing action of the clamping diode, the second switching transistor, and the second resistor.

[0034] According to a third aspect of the embodiments of the present application, a charging protection circuit is provided. The charging protection circuit herein can be understood as a bidirectional protection circuit. When applied to the upper charging circuit, the charging protection circuit can perform overvoltage protection on devices coupled to the power supply terminal and the load terminal of the charging circuit. The charging protection circuit includes a first switching transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The first drain electrode is configured to receive a signal from the second drain electrode, and the second drain electrode is configured to receive a signal from the first drain electrode. In other words, the first switching transistor is a bidirectional switching transistor. The charging protection circuit is coupled to the first drain electrode, the second drain electrode, and the substrate electrode, and is configured to adjust the potential of the substrate electrode to the potential between the first drain electrode and the second drain electrode when the first switching transistor is turned on, and to adjust the potential of the substrate electrode to a lower potential of the first drain electrode and the second drain electrode when the first switching transistor is turned off, and further includes a bidirectional circuit.

[0035] When the first switching transistor is turned on and the potential of the substrate electrode is lower than that of the first drain electrode and the second drain electrode, the on-resistance of the first switching transistor increases due to the back-gate effect. As a result, the performance of the first switching transistor deteriorates. When the first switching transistor is turned off and the potential of the substrate electrode is higher than that of the first drain electrode and the second drain electrode, for example, when VSub - VD2 > 0 V, the substrate electrode induces positive charges, which causes a narrower width of the depletion region in the channel. As a result, the first switching transistor is prone to channel punch-through at a low voltage, and as a result, the breakdown voltage capability is insufficient. Therefore, the charge protection circuit provided in this embodiment of the present application includes a bidirectional circuit. The bidirectional circuit is coupled to the substrate electrode. The bidirectional circuit includes a transistor such as a HEMT device or a MOSFET device and is configured to adjust the potential of the substrate electrode. When the first switching transistor is turned on, the potential of the substrate electrode is adjusted to be approximately equal to the potential of the first drain electrode. Thereby, it is possible to avoid the phenomenon that the turn-on resistance is deteriorated due to the back-gate effect caused by the charge accumulation of the substrate electrode. When the first switching transistor is turned off, the potential of the substrate electrode is adjusted to be approximately equal to the lower potential of the first drain electrode and the second drain electrode. As a result, the breakdown characteristics of the first switching transistor are not affected at all, and it is ensured that the breakdown voltage characteristics of the first switching transistor are not affected. In addition, the first switching transistor in this example is a single-gate bidirectional conduction device and has a small cell size. The single-gate bidirectional conduction device has a smaller characteristic resistance compared to the dual-gate bidirectional conduction device.

[0036] In some embodiments, the bi-directional circuit includes a third switching transistor and a fourth switching transistor. The third gate electrode of the third switching transistor is configured to control the turn-on or turn-off of the third switching transistor. The first electrode of the third switching transistor is coupled to the first drain electrode, and the second electrode of the third switching transistor is coupled to the substrate electrode. The fourth gate electrode of the fourth switching transistor is configured to control the turn-on or turn-off of the fourth switching transistor. The first electrode of the fourth switching transistor is coupled to the second drain electrode, and the second electrode of the fourth switching transistor is coupled to the substrate electrode.

[0037] The third switching transistor and the fourth switching transistor are used as a pull-up switch and a pull-down switch. When the first switching transistor is turned on, the resistances of the third switching transistor and the fourth switching transistor are relatively small, and the potential of the substrate electrode can be quickly pulled up to a high potential. When the first switching transistor is turned off, the resistors of the third switching transistor and the fourth switching transistor are equal to infinity, which hardly affects the turn-off leakage current, thereby solving the problem of turn-off leakage current when the resistors are used as a pull-up circuit and a pull-down circuit.

[0038] In some embodiments, both the third gate electrode and the fourth gate electrode are coupled to the first gate electrode. Both the third gate electrode and the fourth gate electrode are coupled to the first gate electrode, and the three gate electrodes receive the same control signal. As a result, the structure of the charge protection circuit can be simplified, and the requirements for the driving circuit used to provide the control signal for the charge protection circuit are reduced.

[0039] In some embodiments, the first switching transistor, the third switching transistor, and the fourth switching transistor are each high electron mobility transistors, and the first switching transistor, the third switching transistor, and the fourth switching transistor share the same substrate. In this way, the integration degree of the first switching transistor, the third switching transistor, and the fourth switching transistor can be improved, and as a result, the area of the charge protection circuit is reduced.

[0040] According to a fourth aspect of the embodiments of the present application, a driving method of a charge protection circuit is provided. The charge protection circuit includes a first switching transistor and a bidirectional circuit. The first switching transistor includes a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The bidirectional circuit is coupled to the first drain electrode, the second drain electrode, and the substrate electrode. The driving method of the charge protection circuit includes that the first switching transistor is turned on under the control of the first gate electrode, the first drain electrode receives a signal from the second drain electrode, or the second drain electrode receives a signal from the first drain electrode. After the first switching transistor is turned on, the bidirectional circuit adjusts the potential of the substrate electrode to the potential between the first drain electrode and the second drain electrode. After the first switching transistor is turned off under the control of the first gate electrode, and after the first switching transistor is turned off, the bidirectional circuit adjusts the potential of the substrate electrode to the lower potential of the first drain electrode and the second drain electrode.

[0041] When the first switching transistor is turned on and the potential of the substrate electrode is lower than that of the first drain electrode and the second drain electrode, the on-resistance of the first switching transistor increases due to the back-gate effect. As a result, the performance of the first switching transistor deteriorates. When the first switching transistor is turned off and the potential of the substrate electrode is higher than that of the first drain electrode and the second drain electrode, for example, when VSub - VD2 > 0 V, the substrate electrode induces positive charges, which causes a narrower width of the depletion region in the channel. As a result, the first switching transistor is more likely to have a channel punch-through at a low voltage, and as a result, the breakdown voltage capability is insufficient. Therefore, the charge protection circuit provided in this embodiment of the present application includes a bidirectional circuit. The bidirectional circuit is coupled to the substrate electrode. The bidirectional circuit includes a transistor such as a HEMT device or a MOSFET device and is configured to adjust the potential of the substrate electrode. When the first switching transistor is turned on, the potential of the substrate electrode is adjusted to be approximately equal to the potential of the first drain electrode. Thereby, it is possible to avoid the phenomenon that the turn-on resistance is deteriorated due to the back-gate effect caused by the charge accumulation of the substrate electrode. When the first switching transistor is turned off, the potential of the substrate electrode is adjusted to be approximately equal to the lower potential of the first drain electrode and the second drain electrode. As a result, the breakdown characteristics of the first switching transistor are not affected at all, and it is ensured that the breakdown voltage characteristics of the first switching transistor are not affected.

[0042] In some embodiments, the bi-directional circuit includes a third switching transistor and a fourth switching transistor. Adjusting the potential of the substrate electrode to the potential between the first drain electrode and the second drain electrode by the bi-directional circuit includes that the third switching transistor is turned on under the control of the third gate electrode, the fourth switching transistor is turned on under the control of the fourth gate electrode, and the potential of the substrate electrode is adjusted to the potential between the first drain electrode and the second drain electrode by the voltage division effect of the third switching transistor and the fourth switching transistor. Adjusting the potential of the substrate electrode to the potential of the second drain electrode by the bi-directional circuit includes that the third switching transistor is turned off by the control of the third gate electrode, the fourth switching transistor is turned off by the control of the fourth gate electrode, and the potential of the substrate electrode is adjusted to the lower potential of the first drain electrode and the second drain electrode by the voltage division effect of the third switching transistor and the fourth switching transistor.

[0043] The third switching transistor and the fourth switching transistor are used as a pull-up switch and a pull-down switch. When the first switching transistor is turned on, the resistances of the third switching transistor and the fourth switching transistor are relatively small, and the potential of the substrate electrode can be quickly pulled up to a high potential. When the first switching transistor is turned off, the resistors of the third switching transistor and the fourth switching transistor are equal to infinity, which hardly affects the turn-off leakage current, thereby solving the problem of turn-off leakage current when the resistors are used as a pull-up circuit and a pull-down circuit.

[0044] According to a fifth aspect of the embodiments of the present application, a charging protection circuit is provided. The charging protection circuit in this specification can be understood as a bidirectional protection circuit. When applied to the upper charging circuit, the charging protection circuit can perform overvoltage protection on the devices coupled to the power supply terminal and the load terminal of the charging circuit. The charging protection circuit is a high electron mobility transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode. The first drain electrode is configured to receive a signal from the second drain electrode, the second drain electrode is configured to receive a signal from the first drain electrode, the first gate electrode controls whether the high electron mobility transistor is turned on or off, a pull-up circuit including a fifth switching transistor, the fifth gate electrode of the fifth switching transistor is configured to control the turn-on or turn-off of the fifth switching transistor, the first electrode of the fifth switching transistor is coupled to the second drain electrode, the second electrode of the fifth switching transistor is coupled to the substrate electrode, a pull-down circuit coupled to the fixed signal terminal and the substrate electrode and configured to pull down the potential of the substrate electrode to the potential of the fixed signal terminal when the high electron mobility transistor is turned off. The potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode and the second drain electrode. The high electron mobility transistor and the fifth switching transistor share the same substrate.

[0045] When a high electron mobility transistor is turned on and the potential of the substrate electrode is low with respect to the first drain electrode and the second drain electrode, the on-resistance of the high electron mobility transistor increases due to the back-gate effect, and as a result, the performance of the high electron mobility transistor deteriorates. When the high electron mobility transistor is turned off and the potential of the substrate electrode is high with respect to the first drain electrode and the second drain electrode, for example, when VSub - VD2 > 0 V, the substrate electrode induces positive charges, which causes a narrower width of the depletion region in the channel. As a result, in the high electron mobility transistor, channel punch-through is likely to occur at a low voltage, and as a result, the breakdown voltage capability is insufficient. Therefore, the charge protection circuit provided in this embodiment of the present application includes a pull-up circuit and a pull-down circuit. When the high electron mobility transistor is turned on, the pull-down circuit enables the substrate electrode to be an open circuit with respect to the fixed signal terminal, and the pull-up circuit enables the first drain electrode and / or the second drain electrode to be substantially short-circuited with respect to the substrate electrode, and adjusts the potential of the substrate electrode to be equal to or substantially equal to the potential of the second drain electrode. Thereby, it is possible to avoid the phenomenon that the turn-on resistance deteriorates due to the back-gate effect caused by the charge accumulation of the substrate electrode. The pull-down circuit is coupled to the reference ground terminal. When the high electron mobility transistor is turned off, the pull-up circuit enables the first drain electrode and / or the second drain electrode to be an open circuit with respect to the substrate electrode, and the pull-down circuit enables the substrate electrode to be substantially short-circuited with respect to the fixed signal terminal, so that as a result, the potential of the substrate electrode can be adjusted to be substantially equal to the potential of the reference ground terminal, ensuring that the breakdown characteristics of the high electron mobility transistor are not affected at all. Also, a bidirectional HEMT device fabricated using GaN, Ga2O3, or GaAs is used as a switching transistor. Compared with a bidirectional MOSFET device used as a switching transistor, the turn-on impedance of the bidirectional HEMT device can theoretically be reduced by one order of magnitude at the same breakdown voltage. In actual low voltage applications (30 V), the turn-on impedance may also be optimized two or more times.When a 2 mm × 2 mm wafer-level chip scale package is used for packaging, the turn-on impedance of the HEMT device can reach 5 ohms. In addition, the HEMT device has no parasitic diode, has a simpler structure, and has no parasitic NPN transistor structure. When the HEMT device is turned off, the breakdown voltage characteristics can be satisfied without reducing the potential of the substrate electrode to the potential of the reference ground terminal.

[0046] In some embodiments, the pull-up circuit further includes a sixth switching transistor. The sixth gate electrode of the sixth switching transistor and the fifth gate electrode of the fifth switching transistor are both coupled to the first gate electrode. The first electrode of the sixth switching transistor is coupled to the first drain electrode, and the second electrode of the sixth switching transistor is coupled to the substrate electrode. The pull-up circuit and the pull-down circuit both include the fifth switching transistor and the sixth switching transistor. The fifth switching transistor and the sixth switching transistor jointly adjust the potential of the substrate electrode, providing a double guarantee, so that the quality and service life of the charge protection circuit are improved.

[0047] In some embodiments, the pull-down circuit includes a third resistor. The third resistor is separately coupled to the substrate electrode and the fixed signal terminal. The pull-down circuit in the charge protection circuit includes the third resistor. Using the voltage division principle of the resistor, when the high electron mobility transistor is turned off, the substrate electrode is substantially short-circuited to the fixed signal terminal. This structure is simple, easy to implement, and low in cost.

[0048] In some embodiments, the pull-down circuit includes a seventh switching transistor. The seventh gate electrode of the seventh switching transistor is configured to control the turn-on or turn-off of the seventh switching transistor. The first electrode of the seventh switching transistor is coupled to the substrate electrode, and the second electrode of the seventh switching transistor is coupled to the fixed signal terminal. The pull-down circuit in the charge protection circuit includes a seventh switching transistor. When the pull-up circuit is turned on, the pull-down circuit is cut off. The path from the first drain electrode and the second drain electrode of the high electron mobility transistor to the fixed voltage terminal is completely pinched off. The leakage current during the turn-on of the high electron mobility transistor can be further reduced, and the loss from the substrate electrode to the fixed voltage terminal during the turn-on of the high electron mobility transistor is reduced.

[0049] In some embodiments, the pull-down circuit includes an eighth switching transistor. The eighth gate electrode of the eighth switching transistor is configured to control the turn-on or turn-off of the eighth switching transistor. The first electrode of the eighth switching transistor is coupled to the substrate electrode, and the second electrode of the eighth switching transistor is coupled to the fixed signal terminal. The eighth switching transistor and the fifth switching transistor are an N-type switching transistor and a P-type switching transistor, respectively. In the charge protection circuit, the pull-up circuit and the pull-down circuit may use MOSFET devices as switching transistors, and the pull-up circuit and the pull-down circuit are arranged separately from the high electron mobility transistor. During the fabrication of the high electron mobility transistor, the separation between the high electron mobility transistor and the fifth switching transistor and the eighth switching transistor need not be considered, and as a result, the fabrication process of the high electron mobility transistor can be simplified.

[0050] According to the sixth aspect of the embodiment of the present application, a chip including a charging protection circuit according to any one of the first aspect, any one of the third aspect, or any one of the fifth aspect is provided.

[0051] The chip provided in this embodiment of the present application includes the aforementioned charging protection circuit, and the beneficial effects of the chip are the same as those of the charging protection circuit. For reference to the aforementioned related descriptions, details will not be described again in this specification.

[0052] According to the seventh aspect of the embodiment of the present application, a package structure including the chip of the sixth aspect and a package housing is provided, and the chip is packaged within the package housing.

[0053] The package structure provided in this embodiment of the present application includes the aforementioned charging protection circuit, and the beneficial effects of the package structure are the same as those of the charging protection circuit. For reference to the aforementioned related descriptions, details will not be described again in this specification.

[0054] According to the eighth aspect of the embodiment of the present application, an electronic device including the package structure according to the seventh aspect, a printed circuit board, and a load is provided. The package structure is disposed on the printed circuit board and coupled to the printed circuit board, and the package structure is further coupled to the load.

[0055] The electronic device provided in this embodiment of the present application includes the aforementioned charging protection circuit, and the beneficial effects of the electronic device are the same as those of the charging protection circuit. For reference to the aforementioned related descriptions, details will not be described again in this specification.

Brief Description of the Drawings

[0056]

Figure 1A

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Embodiments for Carrying Out the Invention

[0057] Hereinafter, with reference to the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described. It is obvious that the described embodiments are only a part, not all, of the embodiments of the present application.

[0058] The following terms, "first", "second", etc., are merely intended to facilitate the description and should not be understood as indicating relative importance or implication, or as implicitly indicating the amount of the technical features shown. Therefore, the features defined by "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, unless otherwise specified, "a plurality of" means two or more.

[0059] In addition, in the embodiments of this application, orientation terms such as "upper", "lower", "left", and "right" may be defined by the orientation of the components schematically arranged in the accompanying drawings, although not limited thereto. It should be understood that these terms indicating directions may be relative concepts and are used for the description and clarification of "with respect to", and may be correspondingly changed based on the change in the arrangement direction of the components in the attached drawings.

[0060] In the embodiments of this application, unless otherwise specified in the context, throughout this specification and the claims, the term "include" is interpreted as "open and inclusive", that is, "including, but not limited to". In the description of this specification, terms such as "one embodiment", "some embodiments", "exemplary one embodiment", "example", or "some examples" are intended to indicate that a specific feature, structure, material, or feature related to the embodiment or example is included in at least one embodiment or example of the present disclosure. The foregoing schematic expressions of the terms do not necessarily refer to the same embodiment or example. Furthermore, a specific feature, structure, material, or characteristic may be included in any one or more embodiments or examples in any suitable manner.

[0061] When describing some embodiments, the expressions "coupling" and "connection" and their extensions may be used. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical contact or electrical contact with each other. In another example, when describing some embodiments, the term "coupled" may be used to indicate that two or more components are in direct physical contact or electrical contact with each other. However, the term "coupling" may also mean that two or more components do not directly contact each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this specification.

[0062] In the embodiments of this application, the term "and / or" describes the association relationship between related objects and can indicate three relationships. For example, A and / or B can indicate the case where only A exists, the case where both A and B exist, and the case where only B exists, and A and B can be singular or plural. The character " / " generally indicates the "or" relationship between related objects.

[0063] Exemplary implementations are described herein with reference to cross-sectional views and / or plan views and / or equivalent circuit diagrams as idealized exemplary drawings. In the drawings, the thicknesses of layers and regions are enlarged for clarity. Therefore, it can be assumed that the shape of the drawings may change due to manufacturing techniques and / or tolerances, etc. Accordingly, exemplary implementations should not be construed as limited to the shapes of the regions shown herein, but rather include, for example, shape deviations due to manufacturing. For example, an etching region shown as a rectangle typically has bending characteristics. Therefore, the regions shown in the accompanying drawings are essentially examples, and their shapes are not intended to represent the actual shapes of the regions of the device and are not intended to limit the scope of the exemplary implementations.

[0064] In an embodiment of the present application, B being approximately equal to A can be understood as the value of B within the range of A±2 (the range from A - 2 to A + 2) being approximately equal to A.

[0065] Before the embodiments of the present application are described, the following terms that may appear next are first defined.

[0066] 2DEG (two-dimensional electron gas): In a semiconductor heterojunction structure, the discontinuous energy band structure forms a potential well at the interface. Since electrons are trapped in the potential well, electrons basically move along a direction parallel to the interface, and the movement of electrons along the direction perpendicular to the interface is restricted.

[0067] Heterojunction: When two or more different semiconductor materials form a laminated structure, due to the difference in lattice constant and bandgap width between the two materials, an energy band difference exists at the interface between the two materials, and a heterojunction is formed.

[0068] Channel punch-through: A phenomenon in which the depletion regions of the source junction and the drain junction of a field-effect transistor are connected.

[0069] Back-gate effect: When the substrate electrode becomes a negative voltage with respect to the gate electrode, when the transistor is turned on, the channel carrier concentration decreases, and as a result, the turn-on impedance of the transistor decreases.

[0070] Specific resistance: The turn-on impedance of a chip per unit area.

[0071] Substrate electrode: An electrode formed by the substrate in a switching transistor structure.

[0072] Threshold voltage: Generally, the input voltage corresponding to the midpoint of the turning region where the output current changes steeply with respect to the input voltage in the transfer characteristic curve is called the threshold voltage.

[0073] Dynamic resistance: Indicates that the turn-on resistance of a HEMT device changes dynamically when the HEMT device is in the on / off state.

[0074] Channel: A thin conductive semiconductor layer between the source electrode and the drain electrode in a field-effect transistor.

[0075] Parasitic diode: In an N-type metal-oxide-semiconductor (NMOS) structure, the body region under the gate electrode is P-type doped and is usually electrically connected to the source electrode, and N-type doping is carried out between the gate electrode and the drain electrode. In this case, a parasitic pn junction diode exists between the source electrode and the drain electrode, and when the source electrode becomes a high voltage with respect to the drain electrode, the parasitic pn junction diode is turned on.

[0076] One embodiment of the present application provides an electronic device. The electronic device is, for example, a mobile phone, a tablet computer (pad), a notebook computer, an e-reader, a personal digital assistant (PDA), an intelligent wearable product (for example, a smart watch or a smart band), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a drone, a smart lock, a charging household small electrical appliance (for example, a soy milk machine or a robotic vacuum cleaner), a mobile power supply, an adapter or a robot.

[0077] Specifically, the electronic device can be charged and can also charge an external device. The charging may be in a wired or wireless manner. For example, a smart phone can be charged in a wired or wireless manner and can also charge an external device (for example, a smart watch or a smart band) in a reverse charging manner.

[0078] An example where the electronic device is a mobile phone is used below to explain the electronic device provided in this embodiment of the present application.

[0079] As shown in FIG. 1A, the electronic device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging circuit 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headset jack 170D, a sensor 180, a button 190, a motor 191, an indicator 192, a camera 193, a display 194, a subscriber identification module (SIM) card interface 195, and the like.

[0080] It can be understood that the structure shown in this embodiment does not constitute a specific limitation on the electronic device 100. In some other embodiments of the present application, the electronic device 100 may include more or fewer components than those shown in the figure, or some components may be combined, or some components may be divided, or different component arrangements may be used. The components shown in the figure may be implemented by hardware, software, or a combination of software and hardware.

[0081] The processor 110 may include one or more processing units.

[0082] For example, the processor 110 may include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU). Different processing units may be independent components or may be integrated into one or more processors.

[0083] In some embodiments, the electronic device 100 may also include one or more processors 110. The processor 110 may be the nerve center and command center of the electronic device 100. The processor 110 can generate operation control signals based on instruction operation codes and time-series signals to complete the control of instruction fetching and instruction execution.

[0084] Memory may be further disposed in the processor 110 and is configured to store instructions and data.

[0085] In some embodiments, the memory in the processor 110 is a cache. The memory may store instructions or data used by or periodically used by the processor 110. When the processor 110 needs to reuse an instruction or data, the processor 110 can directly call the instruction or data from the memory. This avoids repeated accesses, reduces the latency of the processor 110, and as a result, improves the system efficiency of the electronic device 100.

[0086] In some embodiments, the processor 110 may include one or more interfaces. The interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, a universal serial bus (USB) port, and the like.

[0087] The USB interface 130 is an interface compliant with the USB standard specifications, and specifically may be a Mini USB interface, a Micro USB interface, a USB Type C interface, or the like. The USB interface 130 may be configured to connect to a charger to charge the electronic device 100, may be configured to transmit data between the electronic device 100 and a peripheral device, or may be configured to connect to a headset to play audio using the headset.

[0088] It can be understood that the interface connection relationship between the modules shown in this embodiment of the present invention is merely an example for explanation and does not constitute a limitation on the structure of the electronic device 100. In other embodiments of the present application, the electronic device 100 may alternatively use an interface connection mode different from that in the foregoing embodiments, or may use a combination of multiple interface connection modes.

[0089] The charging circuit 140 is configured to receive a charging input from a charger. The charger may be a wireless charger or a wired charger. The charging circuit 140 can further supply power to the electronic device 100 via the power management module 141 while charging the battery 142.

[0090] In some embodiments of wired charging, the charging circuit 140 may receive the charging input of the wired charger through the USB interface 130.

[0091] In some embodiments of wireless charging, the charging circuit 140 may receive the wireless charging input through the wireless charging coil of the electronic device 100.

[0092] The power management module 141 is configured to connect the battery 142, the charging circuit 140, and the processor 110. The power management module 141 receives the inputs of the battery 142 and / or the charging circuit 140 and supplies power to the processor 110, the internal memory 121, the display 194, the camera 193, the wireless communication module 160, etc. The power management module 141 may be further configured to monitor parameters such as battery capacity, battery cycle count, and battery health state (leakage current or impedance).

[0093] In some embodiments, the power management module 141 may alternatively be disposed within the processor 110. In some other embodiments, the power management module 141 and the charging circuit 140 may alternatively be disposed within the same component.

[0094] From the foregoing description of the electronic device 100, as shown in FIG. 1B, it can be found that the main function of the charging circuit 140 within the electronic device is to charge the load by receiving the charging input transmitted from the power supply terminal.

[0095] For example, the power supply terminal includes a wired power supply terminal including a USB interface and a wireless power supply terminal including a wireless charging coil and a wireless receiving IC (integrated circuit). Of course, the above is only an example of the application of the charging circuit 140 in a mobile phone. The charging circuit 140 can be applied to any electronic device that needs to be charged.

[0096] The structure of the charging circuit 140 provided in this embodiment of the present application is shown in FIG. 1C. The charging circuit 140 includes a drive circuit (or referred to as a driver chip) 10 and a charging protection circuit 20.

[0097] The drive circuit 10 is configured to detect an overvoltage signal and transmit a control signal to the charging protection circuit 20. The charging protection circuit 20 is configured to perform bidirectional protection on the device coupled to the power supply terminal and the load coupled to the load terminal under the control of the control signal. Therefore, the charging protection circuit 20 is an important structure for the charging circuit 140 to have a bidirectional protection function.

[0098] The structure of the drive circuit 10 is shown in FIG. 1D. The drive circuit 10 includes a charge pump 11 and a pulse-width modulation (PWM) module 12.

[0099] The charge pump 11 includes a first input terminal Vi1, a second input terminal Vi2, and an output terminal Vot. The first input terminal Vi1 is coupled to the PWM module 12 and is configured to receive the control logic voltage Vpwm output by the PWM module 12. The second input terminal Vi2 is coupled to the power supply terminal (which may be a wired power supply terminal or a wireless power supply terminal) and is configured to receive the power supply voltage Vsy input by the power supply terminal. The output terminal Vot is coupled to the charging protection circuit 20 and is configured to output a control signal to the charging protection circuit 20.

[0100] In other words, the charge pump 11 is configured to process the received power supply voltage Vsy under the control of the control logic voltage Vpwm, obtain a control signal, and transmit the control signal from the output terminal Vot of the charge pump 11 to the charge protection circuit 20.

[0101] For example, the PWM module 12 is connected to the first input terminal Vi1 of the charge pump 11 and is configured to output the control logic electrode Vpwm to the first input terminal Vi1 of the charge pump 11.

[0102] When the PWM module 12 outputs a turn-on signal, the charge pump 11 receives the turn-on signal Vpwm and boosts the voltage by using the second input terminal Vi2 of the charge pump 11. As a result, the voltage output by the output terminal Vot of the charge pump 11 increases to Vi2 + Vpwm, and Vi2 + Vpwm is output to the charge protection circuit 20 as a control signal. When the PWM module 12 outputs a turn-off signal, for example, Vpwm = GND, after the first input terminal Vi1 of the charge pump 11 receives the turn-off signal, the control signal output from the output terminal Vot is also gradually pulled down to GND.

[0103] In some embodiments, when the control logic voltage Vpwm is at a high potential, the control signal output by the output terminal Vot has a high voltage. When the control logic voltage Vpwm is at a low potential, the control signal output by the output terminal Vot has a low voltage.

[0104] For example, when the control logic voltage Vpwm is at a high potential, the charge pump 11 adds 5 V to the power supply voltage Vsy input from the second input terminal Vi2 and outputs Vsy + 5 V from the output terminal Vot as a control signal. When the control logic voltage Vpwm is at a low potential, the control signal output by the output terminal Vot is 0.

[0105] The charging protection circuit 20 is shown in FIG. 2A. In the application scenarios of the wired and wireless shared charging circuit 140 in the industry, two silicon (Si) oxide semiconductor transistors (metal-oxide-semiconductor field-effect transistors, MOSFETs) are usually connected in series in a back-to-back and source-sharing manner to function as the charging protection circuit 20, and bidirectional protection is implemented for the device coupled to the power supply terminal and the load coupled to the load terminal.

[0106] However, when two Si MOSFETs are connected in series to function as the charging protection circuit 20, the size of the charging protection circuit 20 increases. In addition, the performance such as the turn-on impedance of the bidirectional blocking MOSFET fabricated based on the Si material has basically reached the physical limit of the Si material. As a result, when the Si MOSFET is turned on, the on-resistance of the charging protection circuit 20 formed by the Si MOSFET is large, and as a result, the turn-on loss is large, the circuit efficiency is low, and the heat generation is serious.

[0107] However, the wide bandgap (WBG) semiconductor material represented by GaN (gallium nitride) has advantages such as a larger bandgap width, a higher breakdown electric field strength, and a higher electron saturation velocity, and has become the most promising candidate in the new generation of power electronic devices. In addition, a typical GaN-based device is a high electron mobility transistors (HEMTs) device, and the channel is conducted through a two-dimensional electron gas (2DEG), and there is no parasitic diode. For this reason, the conventional HEMT device has a bidirectional blocking function only by adjusting the position of the gate electrode G.

[0108] As shown in FIG. 2B, the HEMT device includes a substrate, a buffer layer, a channel layer, a barrier layer, a first drain electrode D1, a second drain electrode D2, and a gate electrode G, which are disposed on the substrate. The material of the substrate is usually a conductor or a semiconductor. Therefore, the electrode formed by the substrate is referred to as the substrate electrode Sub. That is, the HEMT device includes the first drain electrode D1, the second drain electrode D2, the gate electrode G, and the substrate electrode Sub. As shown in FIG. 2C, under the control of the gate electrode G, the first drain electrode D1 and the second drain electrode D2 can be conductively connected and cut off in both directions.

[0109] Based on this, as shown in FIG. 2D, the charging protection circuit 20 only requires one HEMT device and does not need to connect two HEMT devices in series. Therefore, the size of the charging protection circuit 20 can be significantly reduced, and the characteristic resistance can be effectively reduced.

[0110] From the above description, it can be found that the charging protection circuit 20 is configured to perform bidirectional protection on the device coupled to the power supply terminal and the load coupled to the load terminal under the control of the drive circuit 10.

[0111] Therefore, in some embodiments, as shown in FIG. 2D, the charging protection circuit 20 is disposed between the wired power supply terminal and the load, and is configured to perform bidirectional protection on the device coupled to the wired power supply terminal and the load coupled to the load terminal.

[0112] In some other embodiments, as shown in FIG. 2E, the charging protection circuit 20 is disposed between the wireless power supply terminal and the load, and is configured to perform bidirectional protection on the device coupled to the wireless power supply terminal and the load coupled to the load terminal.

[0113] It should be understood that the differences between the bidirectional HEMT device and the conventional HEMT device (unidirectional HEMT device) are as follows. The conventional HEMT device includes a source electrode (Source), a drain electrode (Drain), a gate electrode (G), and a substrate electrode (Sub), and the substrate electrode is coupled to the source electrode. Whether the HEMT device is turned on or off, the potential of the substrate electrode Sub is usually equal to the potential of the source electrode. However, the bidirectional HEMT device includes a first drain electrode D1, a second drain electrode D2, a gate electrode G, and a substrate electrode Sub without a source electrode. In order to implement effective bidirectional conduction and bidirectional blocking functions, the substrate electrode Sub needs to be controlled separately. In the application process, if the potential of the substrate electrode Sub is not properly processed, problems such as an increase in the turn-on resistance of the HEMT device and insufficient breakdown voltage may occur.

[0114] Therefore, in order to ensure that the function of the charge protection circuit 20 to which the bidirectional HEMT device is applied is normally implemented and to fully utilize the performance advantages of the HEMT device, the potential of the substrate electrode Sub of the bidirectional HEMT device needs to be controlled.

[0115] The following shows some general methods for controlling the potential of the substrate electrode Sub.

[0116] Method 1 As shown in FIG. 3A, when the bidirectional HEMT device is applied to the charge protection circuit 20, the substrate electrode Sub of the HEMT device is directly grounded. Thereby, even if the potential of the substrate electrode Sub is grounded when the HEMT device is turned off, the breakdown voltage characteristics of the HEMT device are not affected. However, when the HEMT device is turned on, the voltage of the first drain electrode D1 is greater than 0 V. When the substrate electrode Sub is at a low potential with respect to both the first drain electrode D1 and the second drain electrode D2, the performance of the HEMT device is degraded due to the back-gate effect.

[0117] As shown in FIG. 3B, the buffer layer and channel layer of the HEMT device have the equivalent effect of a parasitic capacitance C and a parasitic resistor R with a very large resistance value, and the parasitic capacitance C and the parasitic resistor R are connected in parallel. For example, when the voltage of the first drain electrode D1 is VD1 = 25 V, the parasitic capacitance is charged, a large amount of negative charges are induced inside the substrate electrode Sub (e.g., Si substrate), and fixed charges with positive charges are induced near the channel layer and near the heterojunction between the barrier layer and the channel layer to compensate for the channel electrons, resulting in the expansion of the channel depletion region and the decrease of the 2DEG electron concentration.

[0118] For example, when the buffer layer of the HEMT device is GaN (gallium nitride) with a thickness of 1 μm and VD1 - VSub = 25 V, the surface density of the negative charges induced in the Si substrate electrode Sub is about Q = C×V = 1.3e12 cm-2. In the above formula, Q is the charge amount, C is the capacitance value of the parasitic capacitance, and V is the voltage drop between the substrate electrode Sub and the first drain electrode D1 or the second drain electrode D2. However, the 2DEG concentration of the HEMT device is usually 8 - 10e12 cm-2. As a result, the 2DEG concentration is reduced by about 20% or more. As a result, as shown in FIG. 3C, compared with the threshold voltage (Vth) when VD1 - VSub = 0 V (no bias voltage), the threshold voltage when VD1 - VSub = 25 V (with bias voltage) drifts in the forward direction, and the turn-on resistance increases. Also, at the same gate voltage, the turn-on impedance of the device increases by more than 20%.

[0119] Method 2 As shown in FIG. 4A, when the bidirectional HEMT device is applied to the charge protection circuit 20, the substrate electrode Sub of the HEMT device is directly connected to the first drain electrode D1 or the second drain electrode D2 (in FIG. 4A, an example where the substrate electrode Sub is connected to the first drain electrode D1 is used for illustration).

[0120] In this way, when the HEMT device is turned on, VD1 = VSub ≒ VD2 (when ignoring the voltage drop of the HEMT device, VD1 = VSub = VD2), which is the same as the operating state of the conventional HEMT device, and the DC characteristics such as the threshold voltage and turn-on impedance of the HEMT device are not affected.

[0121] However, as shown in Figure 4B, when the HEMT device is turned off, when VD2 is at a high potential (when the load is wirelessly charged by using the wireless power supply terminal shown in Figure 2D), the HEMT device is equivalent to the conventional HEMT device, and the breakdown characteristics are not affected. However, when VD1 is at a high potential (when a surge occurs in the process of the wired power supply terminal shown in Figure 2D performing wired charging on the load), VD2 is at a low potential, VD1 - VSub = 0 V, and VSub - VD2 > 0 V, the substrate electrode Sub induces positive charges and causes a narrower width of the depletion region in the channel. As a result, as shown in Figure 4C, in the HEMT device, channel punch-through is likely to occur at a low voltage, and as a result, the breakdown voltage capability is insufficient.

[0122] Method 3 As shown in Figure 5A, when the bidirectional HEMT device is applied to the charging protection circuit 20, a floating process is directly performed on the substrate electrode Sub of the HEMT device.

[0123] As shown in Figure 5B, when the HEMT device is turned off, if VD1 is at a high potential and VD1 is at a low potential, the substrate electrode Sub is floated. In this case, the potential of the substrate electrode Sub is affected by the parasitic capacitance, and VSub > 0 V. Therefore, electrons are injected into the second drain electrode D2. A part of the injected electrons is captured by the defects in the epitaxial layer (for example, the buffer layer), and the other part flows to the substrate electrode Sub and is bound to the epitaxial layer / substrate potential well.

[0124] As shown in FIG. 5C, when the HEMT device is turned on, the electrons captured by the epitaxial layer cannot be released in a timely manner, and the electrons trapped in the epitaxial layer / substrate potential well cannot be discharged, causing charge accumulation. As a result, VSub - VD1 < 0 V. Therefore, similar to Method 1, when the HEMT device is turned on, the epitaxial layer and the substrate have negative charges, which have a weakening effect on the channel 2DEG. As a result, the turn-on resistance of the HEMT device increases.

[0125] Referring to the foregoing description, when the bidirectional HEMT device is applied to the charge protection circuit 20, when the substrate electrode Sub of the HEMT device is directly grounded (Method 1), it can be found that the threshold voltage of the HEMT device drifts in the forward direction and the turn-on resistance increases. When the substrate electrode Sub of the HEMT device is coupled to the first drain electrode D1 or the second drain electrode D2 (Method 2), the breakdown voltage capability of the HEMT device is insufficient. When the substrate electrode Sub of the HEMT device is floated (Method 3), the turn-on resistance of the HEMT device increases.

[0126] To solve the above problems, an embodiment of the present application further provides a charge protection circuit 20 configured to process the substrate electrode Sub of the bidirectional HEMT device to ensure the turn-on characteristics during the turn-on of the HEMT device and the breakdown voltage characteristics during the turn-off of the HEMT device.

[0127] Hereinafter, the charge protection circuit 20 provided in this embodiment of the present application will be described by using some detailed examples.

[0128] Example 1 As shown in FIG. 6, the charge protection circuit 20 includes a first switching transistor 21, a pull-up circuit 22, and a pull-down circuit 23.

[0129] The first switching transistor 21 has the characteristics of bidirectional conduction and bidirectional interruption. The first switching transistor 21 has a first drain electrode D1, a second drain electrode D2, a first gate electrode G1, and a substrate electrode Sub. The first drain electrode D1 is configured to receive a signal from the second drain electrode, the second drain electrode D2 is configured to receive a signal from the first drain electrode, and the first gate electrode G1 is configured to control the first switching transistor 21 to be turned on or off.

[0130] In this embodiment of the present application, the first switching transistor 21 may be a HEMT device (for example, a GaN-based HEMT, a Ga2O3-based HEMT, or a GaAs-based HEMT), or the first switching transistor 21 may be a MOSFET device. Of course, the first switching transistor 21 may alternatively be another switching device having a bidirectional conduction function. This is not limited in this embodiment of the present application. Hereinafter, for the sake of explanation, only an example in which the first switching transistor 21 is an N-type HEMT device is used.

[0131] For example, when the charge protection circuit 20 is applied to the electronic device 100, the first drain electrode D1 is coupled to the power supply terminal, the second drain electrode D2 is coupled to the load, and the first gate electrode G1 is coupled to the drive circuit 10. The drive circuit 10 is configured to supply a first control signal to the first gate electrode G1. After receiving the first control signal, the first gate electrode G1 controls the turning on or off of the first switching transistor 21 based on the magnitude of the first control signal. When the first gate electrode G1 controls the first switching transistor 21 to be turned on, the first drain electrode D1 is connected to the second drain electrode D2. When the first control signal controls the first switching transistor 21 to be turned off, the first drain electrode D1 is disconnected from the second drain electrode D2.

[0132] When the load receives power from the power supply terminal (the electronic device 100 is charged), the first drain electrode D1 is configured to receive the power supply voltage Vsy of the power supply terminal and transmit the power supply voltage Vsy to the second drain electrode D2. The second drain electrode D2 transmits the power supply voltage Vsy to the load. In other words, the first drain electrode D1 receives the power supply voltage Vsy provided from the power supply terminal, and the second drain electrode D2 receives a signal (the power supply voltage Vsy transmitted from the first drain electrode D1) from the first drain electrode D1.

[0133] When the load discharges power to the power supply terminal (the electronic device 100 charges an external device), the second drain electrode D2 is configured to receive the power discharged by the load and transmit the discharge voltage to the first drain electrode D1. The first drain electrode D1 transmits the discharge voltage to an external device coupled to the power supply terminal. That is, the second drain electrode D2 receives the discharge voltage provided by the load, and the first drain electrode D1 receives a signal (the discharge voltage transmitted by the second drain electrode D2) from the second drain electrode D2.

[0134] That is, the signal received by the first drain electrode D1 includes the power supply voltage Vsy provided from the power supply terminal and the signal output from the second drain electrode D2, and the signal received by the second drain electrode D2 includes the discharge voltage provided by the load and the signal output from the first drain electrode D1.

[0135] That is, the first drain electrode D1 may be configured to receive a signal or may be configured to output a signal. Similarly, the second drain electrode D2 may be configured to receive a signal or may be configured to output a signal.

[0136] When the first switching transistor 21 is turned on, it should be noted that the voltage drop of the first switching transistor 21 is relatively small. That is, when the first switching transistor 21 is turned on, the voltages of the first drain electrode D1 and the second drain electrode D2 are substantially equal, and the difference therebetween is very small (the difference is the voltage drop of the first switching transistor 21). Therefore, in this embodiment of the present application, it should be understood that when the voltage of the first drain electrode D1 is equal to the voltage of the second drain electrode D2, the voltage drop of the first switching transistor 21 is actually negligible.

[0137] The pull-up circuit 22 is coupled to the first gate electrode G1 and the substrate electrode Sub, and is configured to adjust the potential of the substrate electrode Sub to a threshold value in order to ensure that the turn-on characteristics of the first switching transistor 21 are not affected when the first switching transistor 21 is turned on.

[0138] The pull-up circuit 22 adjusts the potential of the substrate electrode Sub to a threshold value, thereby adjusting the potential of the substrate electrode Sub to a potential that can ensure the turn-on characteristics of the first switching transistor 21 when the first switching transistor 21 is turned on. Therefore, the selection of the threshold value is not limited to this embodiment of the present application as long as the turn-on characteristics of the first switching transistor 21 can be ensured. The threshold value can be adjusted by adjusting the structure of the pull-up circuit 22.

[0139] When the first switching transistor 21 is turned on, as long as the potential of the substrate electrode Sub is equal to or higher than a potential within the range from half of the potential of the first drain electrode D1 to the potential of the first gate electrode G1, or as long as the potential of the substrate electrode Sub is equal to or higher than a potential within the range from half of the potential of the second drain electrode D2 to the potential of the first gate electrode G1, it can be ensured that the turn-on characteristics of the first switching transistor 21 are not affected.

[0140] Therefore, the threshold voltage is a potential that ensures that the turn-on characteristics of the first switching transistor 21 are not affected (for example, the turn-on resistance is not increased). For example, the threshold voltage is any potential within the range from half of the potential of the first drain electrode D1 to the potential of the first gate electrode G1, or any potential within the range from half of the potential of the second drain electrode D2 to the potential of the first gate electrode G1.

[0141] For example, the threshold voltage may be the potential of the first drain electrode D1, the potential of the second drain electrode D2, the potential of the first gate electrode G1, any potential greater than half of the potential of the first drain electrode D1, or any potential greater than half of the potential of the second drain electrode D2. Alternatively, the threshold voltage may be equal to or higher than the lower potential of the first drain electrode D1 and the second drain electrode D2.

[0142] First, the pull-down circuit 23 will be briefly described below, and then the structures of the pull-up circuit 22 and the pull-down circuit 23 will be described in detail.

[0143] The pull-down circuit 23 is coupled to the substrate electrode Sub and the fixed signal terminal, and is configured to adjust the potential of the substrate electrode Sub to the potential of the fixed signal terminal when the first switching transistor 21 is turned off, so as to ensure that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0144] By adjusting the potential of the substrate electrode Sub to the potential of the fixed signal terminal, the pull-down circuit 23 adjusts the potential of the substrate electrode Sub to the potential of the fixed signal terminal that can ensure the breakdown voltage characteristics of the first switching transistor 21 when the first switching transistor 21 is turned off. Therefore, in this embodiment of the present application, as long as the breakdown voltage characteristics of the first switching transistor 21 can be ensured, the potential of the signal transmitted by the fixed signal terminal is not limited.

[0145] In some embodiments, the potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode D1 and the second drain electrode D2 when the first switching transistor 21 is turned off.

[0146] Alternatively, when the first switching transistor 21 is turned off, the potential of the fixed signal terminal is below the potential of the first drain electrode D1, and when the first switching transistor 21 is turned off, the potential of the fixed signal terminal is below the potential of the second drain electrode D2. Alternatively, it can be understood that when the first switching transistor 21 is turned off, the potentials of both the first drain electrode D1 and the second drain electrode D2 are greater than the potential of the fixed signal terminal.

[0147] For example, the potential of the fixed signal terminal is 0 or less. For example, the fixed signal terminal is a reference ground terminal (ground, GND). That is, the potential of the signal transmitted by the fixed signal terminal is 0. Alternatively, the potential of the signal transmitted by the fixed signal terminal is a potential less than 0. Hereinafter, an example in which the fixed signal terminal is the reference ground terminal GND is used for explanation.

[0148] Based on this, the driving process of the charging protection circuit 20 provided in this example includes the following steps.

[0149] During normal wired charging (when the electronic device is charged), the first switching transistor 21 is turned on under the control of the first control signal received by the first gate electrode G1, and the first drain electrode D1 transmits the received power supply voltage Vsy to the second drain electrode D2 for output. At the same time, the pull-up circuit 22 adjusts the potential of the substrate electrode Sub to the threshold value.

[0150] During normal reverse charging (where an electronic device charges an external device), the first switching transistor 21 is turned on under the control of a first control signal received by the first gate electrode G1, and the second drain electrode D2 transmits the received discharge voltage to the first drain electrode D1 for output. At the same time, the pull-up circuit 22 adjusts the potential of the substrate electrode Sub to a threshold value.

[0151] The principle of normal wired charging is the same as that of normal reverse charging. Hereinafter, only normal wired charging will be used as an example for explanation.

[0152] When a surge occurs during wired charging or wireless charging, the first switching transistor 21 is turned off under the control of a first control signal received by the first gate electrode G1, and the pull-down circuit 23 adjusts the potential of the substrate electrode Sub to the potential of the fixed signal terminal.

[0153] Regarding the structures of the pull-up circuit 22 and the pull-down circuit 23, in some embodiments, as shown in FIG. 7A, the pull-up circuit 22 includes a first resistor R1 and a second switching transistor SW2.

[0154] The second gate electrode of the second switching transistor SW2 is coupled to the first gate electrode G1, the first electrode of the second switching transistor SW2 is coupled to the second end of the first resistor R1, and the second electrode of the second switching transistor SW2 is coupled to the substrate electrode Sub.

[0155] The first end of the first resistor R1 is coupled to the first gate electrode G1, and the second end of the first resistor R1 is coupled to the substrate electrode Sub using the second switching transistor SW2.

[0156] Note that the first switching transistor 21 is a bidirectional switching transistor and includes a first drain electrode D1, a second drain electrode D2, a first gate electrode G1, and a substrate electrode Sub. The second switching transistor SW2 is a conventional switching transistor, that is, it includes three ends, namely, a source electrode, a drain electrode, and a second gate electrode. Therefore, the first electrode and the second electrode of the second switching transistor SW2 are the source electrode and the drain electrode with respect to each other. In this embodiment of the present application, unless otherwise specified, the first electrode and the second electrode of the switching transistor are the source electrode and the drain electrode of the switching transistor. Specifically, whether the first electrode is a source electrode or a drain electrode is related to the type of the switching transistor. For example, in Example 1, in FIG. 7A, the first electrode of the second switching transistor SW2 is a drain electrode, and the second electrode of the second switching transistor SW2 is a source electrode.

[0157] The second gate electrode of the second switching transistor SW2 is coupled to the first gate electrode G1 of the first switching transistor 21, and the threshold voltage of the second switching transistor SW2 can be the same as the threshold voltage of the first switching transistor 21. In other words, the first control signal controls the first switching transistor 21 and the second switching transistor SW2 to be turned on and off simultaneously.

[0158] The first control signal controls the turning on or off of the first switching transistor 21 and the second switching transistor SW2. Generally, when the potential difference of the first control signal with respect to the lower potential of the first drain electrode D1 and the second drain electrode D2 is higher than the threshold voltages of the first switching transistor 21 and the second switching transistor SW2, it is considered that the first switching transistor 21 and the second switching transistor SW2 are turned on. When the potential difference of the first control signal with respect to the lower potential of the first drain electrode D1 and the second drain electrode D2 is lower than the threshold voltages of the first switching transistor 21 and the second switching transistor SW2, the first switching transistor 21 and the second switching transistor SW2 are turned off.

[0159] The pull-down circuit includes a second resistor R2. A first end of the second resistor R2 is coupled to the substrate electrode Sub, and a second end of the second resistor R2 is coupled to the reference ground terminal GND.

[0160] In some embodiments, both the first switching transistor 21 and the second switching transistor SW2 may be HEMT devices or MOSFET devices. Certainly, the first switching transistor 21 and the second switching transistor SW2 may alternatively be different types of devices.

[0161] In some embodiments, the first switching transistor 21 and the second switching transistor SW2 share the same substrate electrode Sub.

[0162] In some embodiments, the first resistor R1 is integrated on the substrate electrode Sub.

[0163] In some embodiments, the second resistor R2 is also integrated on the substrate electrode Sub.

[0164] For example, the first switching transistor 21 is a HEMT device, the second switching transistor SW2 is a MOSFET device, and the MOSFET device may be directly formed on the Si substrate of the HEMT device (the Si substrate is the substrate electrode Sub of the HEMT device). The first resistor R1 and the second resistor R2 are formed by using the sheet resistor of the HEMT device, and the metal layers at both ends may be formed in synchronization with the first drain electrode D1 and the second drain electrode D2 of the HEMT device.

[0165] Alternatively, for example, as shown in FIGS. 7B-1 and 7B-2, both the first switching transistor 21 and the second switching transistor SW2 are HEMT devices, and the first switching transistor 21 and the second switching transistor SW2 share the same substrate. The first resistor R1 and the second resistor R2 are formed by using the sheet resistor of the HEMT device, and the metal layers at both ends may be formed in synchronization with the first drain electrode D1 and the second drain electrode D2 of the HEMT device.

[0166] The first switching transistor 21 is selected as a bidirectional HEMT device fabricated using GaN (gallium nitride), Ga2O3 (gallium oxide), or GaAs (gallium arsenide). Compared with a bidirectional MOSFET device, the turn-on impedance of the bidirectional HEMT device can theoretically be reduced by one order of magnitude at the same breakdown voltage. In actual low-voltage applications (30 V), the turn-on impedance may also be optimized more than twice. When a 2 mm × 2 mm wafer level chip scale package (WLCSP) is used for packaging, the turn-on impedance of the HEMT device can reach 5 ohms. In addition, the HEMT device has no parasitic diode, has a simpler structure, and has no parasitic NPN bipolar transistor structure. When the HEMT device is turned off, the breakdown voltage characteristics can be satisfied without reducing the potential of the substrate electrode Sub to the potential of the reference ground terminal GND.

[0167] For example, as shown in FIG. 7C, a method of fabricating the charge protection circuit 20 includes the following steps.

[0168] Step 1: Select a substrate.

[0169] The substrate is used to function as the substrate electrode Sub of the first switching transistor 21. For example, the substrate may be a Si substrate.

[0170] Step 2: Form a nucleation layer on the substrate.

[0171] The method of forming the nucleation layer 40 may be, for example, a metal-organic chemical vapor deposition (MOCVD) chemical vapor deposition method or a molecular beam epitaxy (MBE) growth method.

[0172] The material of the nucleation layer 40 can include, for example, any one or more of GaN, AlGaN (aluminum gallium nitride), and AlN (aluminum nitride).

[0173] The nucleation layer is used to provide nucleation centers and promote the epitaxial growth of the buffer layer.

[0174] Step 3: Form a buffer layer on the nucleation layer.

[0175] As a method for forming the buffer layer, for example, an AlGaN graded layer with a gradually decreasing Al (aluminum) component may be epitaxially grown using the MOCVD method.

[0176] For example, using the MOCVD method, on the nucleation layer, Al 0.8 Ga 0.2 N layer, Al 0.5 Ga 0.5 N layer, Al 0.2 Ga 0.8 N layers and GaN layers are sequentially formed to form the buffer layer.

[0177] Step 4: Form a channel layer on the buffer layer.

[0178] The method for forming the channel layer can be, for example, the MOCVD growth method or the MBE growth method.

[0179] The material of the channel layer can include, for example, one or more of GaN, InGaN, InAlN (indium aluminum nitride), and ScAlN (scandium aluminum nitride).

[0180] Step 5: Form a barrier layer on the channel layer.

[0181] The method for forming the barrier layer can be, for example, the MOCVD growth method or the MBE growth method.

[0182] The material of the barrier layer can include, for example, one or more of AlGaN, InAlN, AlN, ScAlN, and InAlGaN.

[0183] The materials of the channel layer and the barrier layer are different. For example, the material of the channel layer includes GaN, and the material of the barrier layer includes AlGaN.

[0184] Step 6: Form a p-type thin film on the barrier layer.

[0185] The method for forming the p-type thin film can be, for example, the MOCVD growth method or the MBE growth method.

[0186] The material of the gate cap film can be, for example, p-GaN or p-AlGaN.

[0187] Step 7: Form a gate metal layer on the p-type thin film.

[0188] The gate metal layer includes the first gate electrode G1 of the first switching transistor 21 and the second gate electrode G2 of the second switching transistor SW2.

[0189] The method for forming the gate metal layer can be, for example, a pixel synthesis process (including steps such as film formation and photoetching).

[0190] The material of the gate metal layer can be, for example, Ti, TiN, Ni, or palladium (Pd).

[0191] It should be noted that the plurality of first gate electrodes G1 shown in FIG. 7B-1 are only the plurality of signal extraction points of the first gate electrode G1 of the first switching transistor 21, and the plurality of first gate electrodes G1 that function as extraction points receive the first control signal after being combined.

[0192] Step 8: Use the gate metal layer as a mask to etch the p-type thin film to form a gate cap layer.

[0193] The gate cap layer is used to adjust the energy band structure of the heterojunction structure between the barrier layer and the channel layer. As a result, the 2DEG under the gate cap layer is depleted, and the 2DEG in other regions is preserved. In this way, the 2DEG in the HEMT device is in the pinch-off state without a bias voltage, and the 2DEG cannot communicate and flow in the channel layer between the first drain electrode D1 and the second drain electrode D2. The HEMT device is in a closed state. As a result, the HEMT device is a normally closed device. The material of the gate cap layer may be, for example, p-GaN or p-AlGaN.

[0194] Step 9: Remove the epitaxial layer in some regions by deep trench etching (through GaN via, TGV).

[0195] In this step, on the one hand, a cutting path may be formed, and on the other hand, a through hole for connecting the second electrode of the second switching transistor SW2 to the substrate electrode Sub may be formed.

[0196] Step 10: Form a source-drain metal layer.

[0197] The source-drain metal layer includes the first drain electrode D1, the second drain electrode D2, the first and second electrodes of the second switching transistor SW2, the first and second end metals of the first resistor R1, and the first and second end metals of the second resistor R2.

[0198] The method of forming the source-drain metal layer may be, for example, a pixel synthesis process (including steps such as film formation and photoetching).

[0199] The material of the source-drain metal layer may be, for example, a titanium (Ti) layer, an Al layer, a nickel (Ni) layer, and a gold (Au) layer laminated in sequence. That is, the source-drain metal layer is Ti / Al / Ni / Au. Alternatively, the material of the source-drain metal layer may be a Ti layer, an Al layer, a Ti layer, and an Au layer laminated in sequence. That is, the source-drain metal layer is Ti / Al / Ti / Au. Alternatively, the material of the source-drain metal layer may be a Ti layer, an Al layer, and a tin (TiN) layer laminated in sequence. That is, the source-drain metal layer is Ti / Al / TiN. Alternatively, the material of the source-drain metal layer may be a tantalum (Ta) layer, an Al layer, and a TiN layer laminated in sequence. That is, the source-drain metal layer is Ta / Al / TiN. Alternatively, the material of the source-drain metal layer may be a Ta layer, an Al layer, and Ta layers laminated in sequence. That is, the source-drain metal layer is Ta / Al / Ta.

[0200] It should be noted that in the first switching transistor 21 of FIG. 7B-1, a plurality of groups of the first drain electrode D1 and the second drain electrode D2 are shown as an example. However, in practice, the first switching transistor 21 in a circuit application may be simplified to one group of the first drain electrode D1 and the second drain electrode D2. The plurality of first drain electrodes D1 shown in FIG. 7B-1 are only a plurality of signal extraction points of the first drain electrode D1 of the first switching transistor 21, and the plurality of first drain electrodes D1 functioning as extraction points are connected. Similarly, the plurality of second drain electrodes D2 shown in FIG. 7B-1 are only a plurality of signal extraction points of the second drain electrode D2 of the first switching transistor 21, and the plurality of second drain electrodes D2 functioning as extraction points are connected.

[0201] Step 11: Form a separation region between the devices.

[0202] A method for forming a separation region may be, for example, an implantation process or an etching process, as a result of which there is an electronic blocking function between different functional devices.

[0203] In some embodiments, as shown in FIGS. 7B-1 and 7B-2, in order to avoid signal interference between the first switching transistor 21 and the second switching transistor SW2, a separation region is formed between the first switching transistor 21 and the second switching transistor SW2.

[0204] Of course, if necessary, a separation region may also be formed between the second switching transistor SW2 and the second resistor R2. Alternatively, a separation region is formed at another location where a separation region is required to reduce interference between devices. Alternatively, a separation region may not be formed if necessary. That is, in the process of fabricating the charge protection circuit 20, step 11 may not be performed.

[0205] Step 12: Form a passivation layer.

[0206] The via holes in the passivation layer expose the source-drain metal layer and the gate metal layer. The passivation layer is not shown in FIGS. 7B-1 and 7B-2.

[0207] Step 13: Form a wiring layer.

[0208] The wiring layer includes a first wiring 1 that connects a plurality of extraction points of the first drain electrode D1, a second wiring 2 that connects a plurality of extraction points of the second drain electrode D2, a third wiring 3 that connects a plurality of extraction points of the first gate electrode G1, the second gate electrode G2, and a first end of the first resistor R1, and a fourth wiring 4 that connects a second electrode of the second switching transistor SW2 and a first end of the second resistor R2. The second electrode of the second switching transistor SW2 is connected to the substrate electrode Sub, the first end of the second resistor R2 is connected to the second electrode of the second switching transistor SW2 using the wiring 4, and the first end of the second resistor R2 is connected to the substrate electrode Sub.

[0209] It should be noted that step 13 may or may not be included as needed during the fabrication of the charge protection circuit 20. In this embodiment of the present application, an example in which step 13 is included during the fabrication of the charge protection circuit 20 is used for explanation.

[0210] The charge protection circuit 20 fabricated using the above method is shown in FIGS. 7B-1 and 7B-2. In the pull-up circuit 22, the second gate electrode G2 of the second switching transistor SW2 is connected to the first gate electrode G1, the first electrode of the second switching transistor SW2 is connected to the second end of the first resistor R1, and the second electrode of the second switching transistor SW2 is connected to the substrate electrode Sub. The first end of the first resistor R1 is connected to the first gate electrode G1. In the pull-down circuit 23, the first end of the second resistor R2 is connected to the substrate electrode Sub, and the second end of the second resistor R2 is connected to the reference ground terminal GND.

[0211] Based on this, regarding the charging protection circuit 20 shown in FIG. 7A, as shown in FIG. 7D, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned on. The second gate electrode G2 of the second switching transistor SW2 also receives the first control signal, and the threshold voltage of the second switching transistor SW2 may basically be the same as the threshold voltage of the first switching transistor 21. The second gate electrode G2 controls the second switching transistor SW2 to be turned on. If the second switching transistor SW2 is completely turned on, the impedance of the second switching transistor SW2 is much smaller than the impedance of the first resistor R1 and the impedance of the second resistor R2. Therefore, after the first control signal (high-level signal) received by the first gate electrode G1 and controlling the first switching transistor 21 to be turned on passes through the first resistor R1 and the second switching transistor SW2, the potential of the substrate electrode Sub is adjusted to the threshold value (for example, R2 / (R1 + R2)×VG1) by the voltage division action of the first resistor R1 and the second resistor R2, ensuring that the turn-on characteristics of the first switching transistor 21 are not affected.

[0212] That is, the potential VSub of the substrate electrode Sub is approximately VSub = R2 / (R1 + R2)×VG1. That is, the threshold point is about VSub = R2 / (R1 + R2)×VG1. VG1 is the voltage of the first gate electrode G1. Therefore, by adjusting the values of the first resistor R1 and the second resistor R2, or by adjusting the ratio of the first resistor R1 to the second resistor R2, when the first switching transistor 21 is turned off, the potential VSub of the substrate electrode Sub can be randomly adjusted between VD1 and VG1, and the turn-on resistance of the device can be appropriately improved.

[0213] Regarding the selection of the ratio between the first resistor R1 and the second resistor R2, in some embodiments, the ratio between the first resistor R1 and the second resistor R2 is equal to the ratio between the potential of the first gate electrode G1 and the potential of the first drain electrode D1. That is, R1 / R2 = VG1 / VD1.

[0214] In this case, due to the voltage division between the first resistor R1 and the second resistor R2, VSub = VD1, that is, VSub - VD1 = 0. Specifically, the threshold voltage is the voltage of the first drain electrode D1. That is, during normal charging, since the potential of the substrate electrode Sub is adjusted to the potential of the first drain electrode D1, the turn-on impedance of the first switching transistor 21 is not affected. In addition, the gate voltage drop of the second switching transistor SW2 is approximately the gate voltage drop of the first switching transistor 21, and as a result, the reliability of the first gate electrode and the second gate electrode is not affected.

[0215] For example, when the first switching transistor 21 is turned on, VD1 ≒ VD2 = 30 V and VG1 = 35 V. When R1:R2 = VG1:VD1 = 1:6 is selected, VSub = VD1 = VD2 = 30 V.

[0216] By making the voltage drop between the substrate electrode Sub and the first drain electrode D1 relatively small, for example, VSub - VD1 = 0, the leakage current (through the buffer layer) between the substrate electrode Sub and the first drain electrode D1 is relatively small. As a result, the electron trapping effect generated when the potential of the substrate electrode Sub is relatively high is reduced, and the influence on the dynamic impedance is relatively small.

[0217] In some other embodiments, the ratio of the first resistor R1 to the second resistor R2 is smaller than the ratio of the potential of the first gate electrode G1 to the potential of the first drain electrode D1. That is, R1 / R2 < VG1 / VD1.

[0218] In this case, 0 < VSub - VD1 < VG1 - VD1 and VD1 < VSub ≤ VG1. That is, during normal charging, the potential of the substrate electrode Sub is adjusted to be greater than the potential of the first drain electrode D1, so the turn-on impedance of the first switching transistor 21 is not affected. In addition, the gate voltage drop of the second switching transistor SW2 is approximately the same as the gate voltage drop of the first switching transistor 21. As a result, the reliability of the first gate electrode and the second gate electrode is not affected.

[0219] For example, when the first switching transistor 21 is turned on, VD1 ≈ VD2 = 30 V and VG1 = 35 V. If R1:R2 = VG1:VD1 = 2:33 is selected, then VSub = 33 / 35 × 35 = 33 V.

[0220] When the first switching transistor 21 is turned on, the potential of the substrate electrode Sub is appropriately increased, and the positive back-gate effect of the substrate electrode is increased, which helps to increase the 2DEG concentration in the channel of the first switching transistor 21 and reduce the turn-on impedance. Also, by arbitrarily adjusting the potential VSub of the substrate electrode Sub between VD1 and VG1, the turn-on resistance of the device can be appropriately improved.

[0221] In some embodiments, the first resistor R1 is a variable resistor, and the second resistor R2 is a variable resistor.

[0222] In this way, in the driving process of the charge protection circuit 20, the ratio of the first resistor R1 to the second resistor R2 may be adjusted as needed to increase the potential of the substrate electrode Sub, thereby dynamically increasing the 2DEG concentration in the channel of the first switching transistor 21 and achieving the effect of reducing the turn-on impedance.

[0223] On the one hand, the leakage current when the second switching transistor SW2 is turned off is usually on the order of μA, that is, the turn-off impedance is on the order of GΩ. The impedance of the second resistor R2 needs to be smaller than the impedance of the second switching transistor SW2. Therefore, the second resistor R2 cannot be made too large. On the other hand, when the first switching transistor SW1 is turned on, the leakage current between the substrate electrode Sub and the fixed signal terminal needs to be small. Therefore, the second resistor R2 cannot be made too small. Based on this, in some embodiments, the second resistor R2 is in the value range of the order of kΩ to MΩ.

[0224] When a surge occurs at the power supply terminal of the wired charging or during wireless charging, the first control signal received by the first gate electrode G1 changes to a low-level turn-off signal to control the first switching transistor 21 to turn off. In this case, the second switching transistor SW2 is also turned off under the control of the first control signal. When the second switching transistor SW2 is turned off, the impedance of the second switching transistor SW2 + the impedance of the first resistor R1 is much larger than the impedance of the second resistor R2. Therefore, after the first control signal (low-level signal) for controlling the turn-off of the first switching transistor 21 received at the first gate electrode G1 passes through the first resistor R1 and the second switching transistor SW2, due to the voltage division effect of the first resistor R1, the second switching transistor SW2, and the second resistor R2, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal (for example, the potential 0 of the reference ground terminal GND).

[0225] The second resistor R2 is coupled to the fixed signal terminal. When the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal, and the potential of the fixed signal terminal becomes lower than the lower one of the potentials of the first drain electrode D1 and the second drain electrode D2. Therefore, the charge protection circuit 20 can prevent the breakdown characteristics and the breakdown voltage characteristics of the first switching transistor 21 from being affected.

[0226] In the charge protection circuit 20 shown in FIG. 7A, a pull-up circuit 22 is disposed between the first gate electrode G1 of the first switching transistor 21 and the substrate electrode Sub, and a pull-down circuit 23 is disposed between the substrate electrode Sub and the fixed signal terminal. Therefore, the voltage division principle is used, and the ratio of the impedance of the pull-up circuit 22 to the impedance of the pull-down circuit 23 is adjusted. As a result, the potential VSub of the substrate electrode Sub of the first switching transistor 21 during turn-on can satisfy VD1 ≦ VSub ≦ VG1 - Vth_21, where Vth_21 is the threshold voltage of the first switching transistor 21.

[0227] In addition, when the first switching transistor 21 is turned on, the back gate voltage of the substrate electrode Sub is appropriately adjusted. As a result, when a relatively small leakage current is ensured between the substrate electrode Sub and the first drain electrode D1, the 2DEG concentration of the channel can be further adjusted, thereby further reducing the turn-on impedance.

[0228] In addition, the first gate electrode G1 of the first switching transistor 21 and the second gate electrode G2 of the second switching transistor SW2 are coupled to receive the same first control signal, whereby the requirements for the drive circuit 10 can be reduced.

[0229] Regarding the structures of the pull-up circuit 22 and the pull-down circuit 23, in some other embodiments, as shown in FIG. 8A, the pull-up circuit 22 includes a clamping diode 221 and a second switching transistor SW2, and the pull-down circuit 23 includes a second resistor R2.

[0230] The second gate electrode of the second switching transistor SW2 is coupled to the first gate electrode G1 of the first switching transistor 21, the first electrode of the second switching transistor SW2 is coupled to the second end of the clamping diode 221, and the second electrode of the second switching transistor SW2 is coupled to the substrate electrode Sub.

[0231] The first end of the clamping diode 221 is coupled to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamping diode 221 is coupled to the substrate electrode Sub by using the second switching transistor SW2.

[0232] The structure of the pull-down circuit 23 shown in FIG. 8A is the same as the structure of the pull-down circuit 23 shown in FIG. 7A. Refer to the related description, and the details will not be described again in this specification.

[0233] The structure of the pull-up circuit 22 shown in FIG. 8A is different from the pull-up circuit 22 shown in FIG. 7A in that the voltage drop of the clamping diode 221 is used as an equivalent resistor and the voltage division principle is used to adjust the potential of the substrate electrode Sub. For the voltage division principle and the first switching transistor 21 and the second switching transistor SW2, please refer to the related description of the charge protection circuit 20 shown in FIG. 7A.

[0234] Based on this, in the driving process of the charging protection circuit 20, during normal wired charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a turn-on signal, and the first gate electrode G1 controls the first switching transistor 21 to turn on. The threshold voltage of the second switching transistor SW2 is the same as that of the first switching transistor 21, and the second switching transistor SW2 is turned on. The first end of the clamp diode 221 receives the turn-on signal, and as a result, the clamp diode 221 is turned on. The voltage drop of the clamp diode 221 after the clamp diode 221 is turned on reduces the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to a threshold value (for example, VG1 - Vdiode) to ensure that the turn-on characteristics of the first switching transistor 21 are not affected.

[0235] The threshold value can be adjusted by adjusting the voltage drop Vdiode of the clamp diode 221 after the clamp diode 221 is turned on.

[0236] That is, the clamp diode 221 is equivalent to the first resistor R1. Therefore, for the selection of the clamp diode 221 and the second resistor R2, the aforementioned selection principle of the first resistor R1 and the second resistor R2 can be referred to.

[0237] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a turn-off signal, and the first gate electrode G1 controls the first switching transistor 21 to turn off. The threshold voltage of the second switching transistor SW2 is the same as the threshold voltage of the first switching transistor 21, and the second gate electrode G2 controls the second switching transistor SW2 to turn off. When the second switching transistor SW2 is turned off, the impedance of the second switching transistor SW2 + the impedance of the clamp diode 221 is much larger than the impedance of the second resistor R2. Therefore, after the first control signal received by the first gate electrode G1 and controlling the first switching transistor 21 to turn off passes through the clamp diode 221 and the second switching transistor SW2, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal (for example, the potential 0 of the reference ground terminal GND) by the voltage dividing action of the clamp diode 221, the second switching transistor SW2, and the second resistor R2. The second resistor R2 is coupled to the fixed signal terminal. When the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal, ensuring that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0238] Regarding the clamp diode 221, in some embodiments, as shown in FIG. 8B, the first end of the clamp diode 221 is the anode and is coupled to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamp diode 221 is the cathode and is coupled to the substrate electrode Sub by using the second switching transistor SW2.

[0239] For example, the clamp diode 21 is a PN diode, a Schottky barrier diode (SBD), or an equivalent diode formed by short-circuiting the source electrode and the gate electrode in a transistor.

[0240] The transistor may be, for example, a metal oxide thin film transistor or a HEMT.

[0241] Regarding the number of the clamp diodes 221, as shown in FIG. 8B, the pull-up circuit 22 includes one clamp diode 221.

[0242] Alternatively, as shown in FIG. 8C, the pull-up circuit 22 includes a plurality of clamp diodes connected in series.

[0243] The plurality of clamp diodes 221 connected in series can be understood as follows. The anode of the clamp diode 221 closest to the first gate electrode G1 is coupled to the first gate electrode G1, and the cathode of the clamp diode 221 closest to the first gate electrode G1 is coupled to the anode of the next clamp diode 221. Similarly, the cathode of the clamp diode 221 is coupled to the anode of another clamp diode 221. The cathode of the clamp diode 221 closest to the second switching transistor SW2 is coupled to the first electrode of the second switching transistor SW2.

[0244] For example, the plurality of clamp diodes 221 connected in series may be, for example, a plurality of PN diodes having a threshold voltage Vth = 0.7 V / single level connected in series, or a plurality of Schottky barrier diodes having a threshold voltage Vth ≈ 0.3 V / single level connected in series.

[0245] As shown in FIGS. 8D-1 and 8D-2, in a conventional HEMT device, an example in which the pull-up circuit 22 includes two diodes formed by short-circuiting the source electrode and the gate electrode is used to explain the manufacturing method of the charge protection circuit 20 shown in FIG. 8A.

[0246] The manufacturing method of the charge protection circuit 20 shown in FIGS. 8D-1 and 8D-2 has the same steps as the manufacturing method of the charge protection circuit shown in FIG. 7C. The differences are that the structure of the gate metal layer formed in step 7 is different, the structure of the source-drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0247] For example, the method of manufacturing the charge protection circuit 20 includes the following steps.

[0248] Step 1: Select a substrate.

[0249] Step 2: Form a nucleation layer on the substrate.

[0250] Step 3: Form a buffer layer on the nucleation layer.

[0251] Step 4: Form a channel layer on the buffer layer.

[0252] Step 5: Form a barrier layer on the channel layer.

[0253] Step 6: Form a p-type thin film on the barrier layer.

[0254] Step 7: Form a gate metal layer on the p-type thin film.

[0255] As shown in FIGS. 8D-1 and 8D-2, the gate metal layer includes the first gate electrode G1 of the first switching transistor 21, the second gate electrode G2 of the second switching transistor SW2, and the gate electrode G of the HEMT device used as a diode.

[0256] Step 8: Etch the p-type thin film by using the gate metal layer as a mask to form a gate cap layer.

[0257] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0258] Step 10: Form a source-drain metal layer.

[0259] As shown in FIGS. 8D-1 and 8D-2, the source-drain metal layer includes a first drain electrode D1, a second drain electrode D2, a first electrode and a second electrode of a second switching transistor SW2, a source electrode S and a drain electrode D of a HEMT device used as a diode, and a first end metal and a second end metal of a second resistor R2.

[0260] Step 11: Form a separation region between devices.

[0261] Step 12: Form a passivation layer.

[0262] Step 13: Form a wiring layer.

[0263] As shown in FIGS. 8D-1 and 8D-2, the wiring layer includes a first wiring 1 connecting a plurality of extraction points of the first drain electrode D1, a second wiring 2 connecting a plurality of extraction points of the second drain electrode D2, a third wiring 3 connecting a plurality of extraction points of a first gate electrode G1, a second gate electrode G2 and a gate electrode G (anode of the clamp diode 221) of a HEMT device used as a diode, a fourth wiring 4 connecting the second electrode of the second switching transistor SW2 and the first end of the second resistor R2, and a fifth wiring 5 connecting the drain electrode D (cathode of the clamp diode 221) of a HEMT device used as a diode and the first electrode of the second switching transistor SW2.

[0264] The charging protection circuit 20 fabricated using the above method is shown in FIGS. 8D-1 and 8D-2. In the pull-up circuit 22, the second gate electrode of the second switching transistor SW2 is coupled to the first gate electrode G1 of the first switching transistor 21, the first electrode of the second switching transistor SW2 is coupled to the second end of the clamp diode 221, and the second electrode of the second switching transistor SW2 is coupled to the substrate electrode Sub. The first end of the clamp diode 221 is coupled to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamp diode 221 is coupled to the substrate electrode Sub via the second switching transistor SW2. In the pull-down circuit 23, the first end of the second resistor R2 is coupled to the substrate electrode Sub, and the second end of the second resistor R2 is coupled to the reference ground terminal GND.

[0265] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 8C, as shown in FIG. 8E, during normal wired charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a high-level turn-on signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned on. The threshold voltage of the second switching transistor SW2 is the same as the threshold voltage of the first switching transistor 21, and the second switching transistor SW2 is also turned on under the control of the second gate electrode G2. The first end of the clamp diode 221 receives a high-level turn-on signal, and as a result, the clamp diode 221 is turned on in the forward direction. The clamp voltage of the clamp diode 221 reduces the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to a threshold value (e.g., VG1 - Vdiode) to ensure that the turn-on characteristic of the first switching transistor 21 is not affected.

[0266] The threshold value can be adjusted by adjusting the voltage drop Vdiode of the clamp diode 221 after the clamp diode 221 is turned on.

[0267] For example, when the diode 221 is turned on, the number of stages of the multi-stage series-connected clamp diode 221 is adjusted so that the voltage drop Vdiode of the multi-stage series-connected clamp diode 221 changes from 0 to VG1 - VD1. For this reason, the potential of the substrate electrode Sub changes from VD1 to VG1.

[0268] For example, when the first switching transistor 21 is turned on, VG1 = VD1 + 5 V, and the pull-up circuit 22 includes seven stages of PN diodes connected in series. The turn-on voltage drop of one PN diode is, for example, 0.7 V. In this case, VSub = VG1 - Vdiode ≒ VD1. That is, during normal charging, since the potential of the substrate electrode Sub is adjusted to the potential of the first drain electrode D1, the turn-on impedance of the first switching transistor 21 is not affected. In addition, the gate voltage drop of the second switching transistor SW2 is approximately the gate voltage drop of the first switching transistor 21. As a result, the reliability of the first gate electrode and the second gate electrode is not affected.

[0269] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a low-level turn-off signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned off. The threshold voltage of the second switching transistor SW2 is the same as the threshold voltage of the first switching transistor 21, and the second switching transistor SW2 is also turned off under the control of the second gate electrode G2. When the second switching transistor SW2 is turned off, the drive current of the clamp diode 221 is reduced, and the clamp diode 221 is cut off. When the second switching transistor SW2 is turned off and the clamp diode 221 is cut off, the impedance of the second switching transistor SW2 + the impedance of the clamp diode 221 becomes much larger than the impedance of the second resistor R2. Therefore, the first control signal (low-level signal) for controlling the turn-off of the first switching transistor 21 received at the first gate electrode G1 passes through the clamp diode 221 and the second switching transistor SW2, and then, due to the voltage division effect of the clamp diode 221, the second switching transistor SW2, and the second resistor R2, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal (for example, the potential 0 of the reference ground terminal GND). The second resistor R2 is coupled to the fixed signal terminal. When the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal, ensuring that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0270] Regarding the clamp diode 221, in some embodiments, as shown in FIG. 8F, the first end of the clamp diode 221 is the cathode, which is coupled to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamp diode 221 is the anode, which is coupled to the substrate electrode Sub by using the second switching transistor SW2.

[0271] For example, the clamp diode 221 is a zener diode.

[0272] Regarding the number of the clamp diodes 221, as shown in FIG. 8F, the pull-up circuit 22 includes one clamp diode 221.

[0273] Alternatively, as shown in FIG. 8G, the pull-up circuit 22 includes a plurality of clamp diodes connected in series.

[0274] The plurality of clamp diodes 221 connected in series can be understood as follows. The cathode of the clamp diode 221 closest to the first gate electrode G1 is coupled to the first gate electrode G1, and the anode of the clamp diode 221 closest to the first gate electrode G1 is coupled to the cathode of the next clamp diode 221. Similarly, the anode of a clamp diode 221 is coupled to the cathode of another clamp diode 221. The anode of the clamp diode 221 closest to the second switching transistor SW2 is coupled to the first electrode of the second switching transistor SW2.

[0275] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 8F, as shown in FIG. 8E, during normal wired charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a high-level turn-on signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned on. The threshold voltage of the second switching transistor SW2 is the same as that of the first switching transistor 21, and the second switching transistor SW2 is also turned on under the control of the second gate electrode G2. The first end of the clamp diode 221 receives a high-level turn-on signal, and as a result, the clamp diode 221 is turned on in the reverse direction. The reverse clamp voltage of the clamp diode 221 reduces the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to a threshold value (for example, VG1 - Vdiode) to ensure that the turn-on characteristic of the first switching transistor 21 is not affected.

[0276] By changing the structure of the Zener diode and adjusting the value of the reverse clamp voltage of the clamp diode 221, the threshold value can be adjusted. As a result, when the clamp diode 221 is turned on in the reverse direction, the voltage drop Vdiode of the clamp diode 221 changes from 0 to VG1, VD1. Therefore, the potential of the substrate electrode Sub changes from VD1 to VG1.

[0277] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 and the second gate electrode G2 is a low-level turn-off signal, and the first gate electrode G1 controls the first switching transistor 21 to turn off. The threshold voltage of the second switching transistor SW2 is the same as that of the first switching transistor 21, and the second switching transistor SW2 is also turned off under the control of the second gate electrode G2. The drive current of the clamp diode 221 is reduced, and the clamp diode 221 enters a cut-off state. When the second switching transistor SW2 is turned off, the impedance of the second switching transistor SW2 + the impedance of the clamp diode 221 is much larger than the impedance of the second resistor R2. Therefore, after the first control signal (low-level signal) for controlling the turn-off of the first switching transistor 21 received by the first gate electrode G1 passes through the clamp diode 221 and the second switching transistor SW2, due to the voltage division effect of the clamp diode 221, the second switching transistor SW2, and the second resistor R2, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal (for example, the potential 0 of the reference ground terminal GND). The second resistor R2 is coupled to the fixed signal terminal. When the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal, ensuring that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0278] In the charging protection circuit 20 shown in FIG. 8A, a clamping diode 221 is used as a core component of the pull-up circuit 22, and the potential VSub of the substrate electrode Sub can be adjusted using only the voltage VG1 of the first gate electrode of the first switching transistor 21 and the clamping voltage Vdiode of the clamping diode 221. Based on this, in the charging protection circuit 20 of this example, a pull-up circuit 22 is arranged between the first gate electrode G1 and the substrate electrode Sub, and a pull-down circuit 23 is arranged between the substrate electrode Sub and the fixed signal terminal. Therefore, when the first switching transistor 21 is turned on, the pull-up circuit 22 and the pull-down circuit 23 set the voltage bias between the first gate electrode G1 and the substrate electrode Sub to the desired potential, and the potential of the substrate electrode Sub is adjusted to the threshold value (for example, the same as or substantially the same as the potentials of the first drain electrode D1 and the second drain electrode D2). Thereby, it is possible to avoid the phenomenon that the turn-on resistance deteriorates due to the negative back-gate effect caused by the charge accumulation in the substrate electrode Sub. On the other hand, when the first switching transistor 21 is turned off, the voltage of the first gate electrode G1 gradually decreases, and the potential of the substrate electrode Sub decreases together with the potential of the first gate electrode G1. On the other hand, the pull-up circuit 22 enables the first gate electrode G1 to be almost open-circuited with respect to the substrate electrode Sub, and the pull-down circuit 23 enables the substrate electrode Sub to be almost short-circuited with respect to the fixed signal terminal, so as to adjust the potential of the substrate electrode Sub to be almost equal to the potential of the reference ground terminal GND. Therefore, the breakdown characteristics of the first switching transistor 21 are not affected at all.

[0279] Example 2 The difference between Example 2 and Example 1 is that the pull-up circuit 22 does not include the second switching transistor SW2, and as a result, the structure is relatively simplified. In this way, when the first switching transistor 21 is turned off, the pull-down circuit 23 adjusts the potential of the substrate electrode Sub to the potential between the potential of the first gate electrode G1 during the turn-off of the first switching transistor 21 and the potential of the fixed signal terminal, and is configured not to adjust the potential to the potential of the fixed signal terminal any more.

[0280] As shown in FIG. 9A, the charging protection circuit 20 includes a first switching transistor 21, a pull-up circuit 22, and a pull-down circuit 23.

[0281] The effect of the first switching transistor 21 may be the same as that of the first switching transistor 21 shown in Example 1. For reference to the related description of the first switching transistor 21 in Example 1, details are not described again in this specification.

[0282] The pull-up circuit 22 is coupled to the first gate electrode G1 and the substrate electrode Sub, and is configured to adjust the potential of the substrate electrode Sub to a threshold value when the first switching transistor 21 is turned on.

[0283] The pull-down circuit 23 is coupled to the substrate electrode Sub and the fixed signal terminal, and is configured to adjust the potential of the substrate electrode Sub to a potential between the potential of the first gate electrode G1 (the potential during the turn-off of the first switching transistor 21) and the fixed signal terminal when the first switching transistor 21 is turned off.

[0284] Based on this, the driving process of the charging protection circuit 20 provided in this example includes the following steps.

[0285] During normal wired charging (when the electronic device is charged), the first switching transistor 21 is turned on under the control of the first control signal received by the first gate electrode G1, and the first drain electrode D1 transmits the received power supply voltage Vsy to the second drain electrode D2 for output. At the same time, the pull-up circuit 22 adjusts the potential of the substrate electrode Sub to a threshold value.

[0286] During normal reverse charging (where an electronic device charges an external device), the first switching transistor 21 is turned on under the control of a first control signal received by the first gate electrode G1, and the second drain electrode D2 transmits the received discharge voltage to the first drain electrode D1 for output. At the same time, the pull-up circuit 22 adjusts the potential of the substrate electrode Sub to a threshold value.

[0287] The principle of normal wired charging is the same as that of normal reverse charging. Hereinafter, only normal wired charging is used as an example for explanation.

[0288] When a surge occurs during wired charging or wireless charging, the first switching transistor 21 is turned off under the control of a first control signal received by the first gate electrode G1, and the pull-down circuit 23 adjusts the potential of the substrate electrode Sub to the potential between the first gate electrode G1 and the fixed signal terminal.

[0289] In some embodiments, as shown in FIG. 9A, the pull-up circuit 22 includes a first resistor R1. The first end of the first resistor R1 is coupled to the first gate electrode G1, and the second end of the first resistor R1 is coupled to the substrate electrode Sub. In this case, the pull-up circuit 22 is also referred to as a pull-up resistor.

[0290] The pull-down circuit 23 includes a second resistor R2. The first end of the second resistor R2 is coupled to the substrate electrode Sub, and the second end of the second resistor R2 is coupled to a fixed signal terminal (e.g., a reference ground terminal GND). In this case, the pull-up circuit 23 may also be referred to as a pull-down resistor.

[0291] That is, the difference between the charging protection circuit 20 shown in FIG. 9A and the charging protection circuit 20 shown in FIG. 7A is that in the charging protection circuit 20 shown in FIG. 9A, the pull-up circuit 22 includes the first resistor R_1 and does not include the second switching transistor SW2.

[0292] In some embodiments, the first resistor R1 and / or the second resistor R2 are integrated on the substrate of the first switching transistor 21.

[0293] Based on this, for example, during the fabrication of the charging protection circuit 20, the fabrication method is the same as the fabrication method procedure shown in FIG. 7C. As shown in FIG. 9B, the second switching transistor 22 does not need to be fabricated synchronously with the first switching transistor 21.

[0294] For example, the method of fabricating the charging protection circuit 20 has the same steps as the method of fabricating the charging protection circuit shown in FIG. 7C. The difference lies in that the structure of the gate metal layer formed in step 7 is different, the structure of the source-drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0295] For example, the method of fabricating the charging protection circuit 20 includes the following steps.

[0296] Step 1: Select a substrate.

[0297] Step 2: Form a nucleation layer on the substrate.

[0298] Step 3: Form a buffer layer on the nucleation layer.

[0299] Step 4: Form a channel layer on the buffer layer.

[0300] Step 5: Form a barrier layer on the channel layer.

[0301] Step 6: Form a p-type thin film on the barrier layer.

[0302] Step 7: Form a gate metal layer on the p-type thin film.

[0303] As shown in FIG. 9B, the gate metal layer includes the first gate electrode G1 of the first switching transistor 21.

[0304] Step 8: Etch the p-type thin film by using the gate metal layer as a mask to form a gate cap layer.

[0305] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0306] Step 10: Form a source / drain metal layer.

[0307] As shown in FIG. 9B, the source / drain metal layer includes a first drain electrode D1, a second drain electrode D2, the first and second end metals of the first resistor R1, and the first and second end metals of the second resistor R2.

[0308] Step 11: Form a separation region between devices.

[0309] Step 12: Form a passivation layer.

[0310] Step 13: Form a wiring layer.

[0311] As shown in FIG. 9B, the wiring layer includes a first wiring 1 that connects a plurality of extraction points of the first drain electrode D1, a second wiring 2 that connects a plurality of extraction points of the second drain electrode D2, a third wiring 3 that connects a plurality of extraction points of the first gate electrode G1 and the first end of the first resistor R1, and a fourth wiring 4 that connects the second end of the first resistor R1 and the first end of the second resistor R2.

[0312] The charging protection circuit 20 fabricated by the above method is shown in FIG. 9B. The first end of the first resistor R1 of the pull-up circuit 22 is coupled to the first gate electrode G1, and the second end of the first resistor R1 of the pull-up circuit 22 is coupled to the substrate electrode Sub. The first end of the second resistor R2 in the pull-down circuit 23 is coupled to the substrate electrode Sub, and the second end of the second resistor R2 in the pull-down circuit 23 is coupled to the reference ground terminal GND.

[0313] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 9A, as shown in FIG. 9C, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the first switching transistor 21 is controlled to be turned on. After the first control signal (high-level signal) received by the first gate electrode G1 and controlling the first switching transistor 21 to be turned on passes through the first resistor R1, the potential of the substrate electrode Sub is adjusted to the threshold value by the voltage division action of the first resistor R1 and the second resistor R2, ensuring that the turn-on characteristics of the first switching transistor 21 are not affected.

[0314] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the first switching transistor 21 is controlled to be turned off. After the first control signal (low-level signal) received at the first gate electrode G1 and controlling the first switching transistor 21 to be turned off passes through the first resistor R1 and the second switching transistor SW2, due to the voltage division action of the first resistor R1 and the second resistor R2, the potential of the substrate electrode Sub is adjusted to the potential between the first gate electrode G1 and the fixed signal terminal.

[0315] When the first switching transistor 21 is turned off, as long as the potential of the substrate electrode Sub is less than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2, it can be ensured that the breakdown voltage characteristics of the first switching transistor 21 are not affected. Generally, when the first switching transistor 21 is turned off, the potential of the first gate electrode G1 is lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2, and the potentials of the first drain electrode D1 and the second drain electrode D2 are both greater than 0. Therefore, the potential of the substrate electrode Sub is adjusted to the potential between the first gate electrode G1 and the fixed signal terminal. As a result, it can be ensured that the potential of the substrate electrode Sub is less than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2, and the breakdown characteristics and breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0316] For example, when the first switching transistor 21 is turned off, the potentials of the first gate electrode G1, the first drain electrode D1, and the second drain electrode D2 are all greater than 0, and the potential of the fixed signal terminal is 0 or less. Since the potential of the first gate electrode G1 is lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2, if the potential of the substrate electrode Sub is between the first gate electrode G1 and the fixed signal terminal, the potential of the substrate electrode Sub is surely lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2.

[0317] For example, the potential of the first gate electrode G1 is 2, and the potential of the fixed signal terminal is 0. The potential of the substrate electrode Sub is 0, which is lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2.

[0318] Alternatively, for example, the potential of the first gate electrode G1 is 0 or less, and the potential of the fixed signal terminal is 0 or less. If the potential of the substrate electrode Sub is between the first gate electrode G1 and the fixed signal terminal, the potential of the substrate electrode Sub will surely be less than 0. Generally, the potential of the first drain electrode D1 and the potential of the second drain electrode D2 are both greater than 0. Therefore, the potential of the substrate electrode Sub will surely be lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2.

[0319] For example, the potential of the first gate electrode G1 is -2, and the potential of the fixed signal terminal is 0. The potential of the substrate electrode Sub is -1, which is lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2.

[0320] For example, the potential of the first gate electrode G1 is 0, and the potential of the fixed signal terminal is 0. The potential of the substrate electrode Sub is 0, which is approximately equal to the potential of the first gate electrode G1 and lower than the lower of the potentials of the first drain electrode D1 and the second drain electrode D2.

[0321] Regarding the principle of selecting the resistance values of the first resistor R1 and the second resistor R2, please refer to the relevant description in Example 1, and the details will not be described again in this specification.

[0322] In some other embodiments, as shown in FIG. 9D, the pull-up circuit 22 includes a clamping diode 221. The first end of the clamping diode 221 is coupled to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamping diode 221 is coupled to the substrate electrode Sub.

[0323] The pull-down circuit 23 includes a second resistor R2. The first end of the second resistor R2 is coupled to the substrate electrode Sub, and the second end of the second resistor R2 is coupled to a fixed signal terminal (e.g., a reference ground terminal GND).

[0324] For example, as shown in FIG. 9D, the clamp diode 21 is a PN diode, a Schottky barrier diode (SBD), an equivalent diode formed by short - circuiting the source electrode and the gate electrode in a transistor, or the like. The first end of the clamp diode 221 is the anode, and the second end of the clamp diode 221 is the cathode. The anode of the clamp diode 221 is coupled to the first gate electrode G1, and the cathode of the clamp diode 221 is coupled to the substrate electrode Sub.

[0325] There may be one or more clamp diodes 21. In this specification, only an example in which a plurality of clamp diodes 21 exist is used for the purpose of explanation.

[0326] In other words, the structural difference between the charge protection circuit 20 shown in FIG. 9D and the charge protection circuit 20 shown in FIG. 8C is that the pull - up circuit 22 in the charge protection circuit 20 shown in FIG. 9D does not include the second switching transistor SW2.

[0327] Based on this, for example, during the fabrication of the charge protection circuit 20, the fabrication method is the same as the fabrication method procedure shown in FIG. 7C. As shown in FIGS. 9E - 1 and 9E - 2, the second switching transistor 22 does not need to be fabricated synchronously with the first switching transistor 21.

[0328] For example, the method of fabricating the charge protection circuit 20 has the same steps as the method of fabricating the charge protection circuit shown in FIG. 7C. The differences are that the structure of the gate metal layer formed in step 7 is different, the structure of the source - drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0329] For example, the method of fabricating the charge protection circuit 20 includes the following steps.

[0330] Step 1: Select a substrate.

[0331] Step 2: Form a nucleation layer on the substrate.

[0332] Step 3: Form a buffer layer on the nucleation layer.

[0333] Step 4: Form a channel layer on the buffer layer.

[0334] Step 5: Form a barrier layer on the channel layer.

[0335] Step 6: Form a p-type thin film on the barrier layer.

[0336] Step 7: Form a gate metal layer on the p-type thin film.

[0337] As shown in FIGS. 9E-1 and 9E-2, the gate metal layer includes the first gate electrode G1 of the first switching transistor 21 and the gate electrode G of the HEMT device used as a diode.

[0338] Step 8: By using the gate metal layer as a mask, etch the p-type thin film to form a gate cap layer.

[0339] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0340] Step 10: Form a source-drain metal layer.

[0341] As shown in FIGS. 9E-1 and 9E-2, the source-drain metal layer includes the first drain electrode D1, the second drain electrode D2, the source electrode S and the drain electrode D of the HEMT device used as a diode, and the first end metal and the second end metal of the second resistor R2.

[0342] Step 11: Form a separation region between the devices.

[0343] Step 12: Form a passivation layer.

[0344] Step 13: Form a wiring layer.

[0345] As shown in FIGS. 9E-1 and 9E-2, the wiring layer includes a first wiring 1 that connects a plurality of extraction points of the first drain electrode D1, a second wiring 2 that connects a plurality of extraction points of the second drain electrode D2, a third wiring 3 that connects a plurality of extraction points of the first gate electrode G1 and the gate electrode G (the anode of the clamp diode 221) of the HEMT device used as a diode, and a fourth wiring 4 that connects the drain electrode D (the cathode of the clamp diode 221) of the HEMT device used as a diode and the first end of the second resistor R2.

[0346] The charge protection circuit 20 fabricated using the above method is shown in FIGS. 9E-1 and 9E-2. The first end of the clamp diode 221 in the pull-up circuit 22 is connected to the first gate electrode G1 of the first switching transistor 21, and the second end of the clamp diode 221 is connected to the substrate electrode Sub. The first end of the second resistor R2 in the pull-down circuit 23 is connected to the substrate electrode Sub, and the second end of the second resistor R2 is connected to the reference ground terminal GND.

[0347] Based on this, in the driving process of the charge protection circuit 20 shown in FIG. 9D, as shown in FIG. 9C, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned on. The first end of the clamp diode 221 receives the high-level turn-on signal, and as a result, the clamp diode 221 is turned on in the forward direction. The clamp voltage of the clamp diode 221 reduces the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to the threshold value to ensure that the turn-on characteristics of the first switching transistor 21 are not affected.

[0348] When a surge occurs during wired charging or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned off. The first end of the clamp diode 221 receives the low-level turn-off signal, and as a result, the clamp diode 221 is cut off. The potential of the substrate electrode Sub is adjusted to the potential of the fixed signal terminal (for example, the potential 0 of the reference ground terminal GND) by the voltage dividing action of the clamp diode 221 and the second resistor R2. The second resistor R2 is coupled to the fixed signal terminal. When the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to the potential between the first gate electrode G1 and the fixed signal terminal, ensuring that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0349] For example, as shown in FIG. 9F, the clamp diode 221 is a Zener diode. The first end of the clamp diode 221 is the cathode, and the second end of the clamp diode 221 is the anode. The cathode of the clamp diode 221 is coupled to the first gate electrode G1, and the anode of the clamp diode 221 is coupled to the substrate electrode Sub.

[0350] There may be one or more clamp diodes 21. In this specification, only one clamp diode 21 is used as an example for explanation.

[0351] In other words, the structural difference between the charging protection circuit 20 shown in FIG. 9F and the charging protection circuit 20 shown in FIG. 8F lies in that the pull-up circuit 22 in the charging protection circuit 20 shown in FIG. 9F does not include the second switching transistor SW2.

[0352] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 9F, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the first switching transistor 21 is controlled to be turned on. The first end of the clamp diode 221 receives the high-level turn-on signal, and as a result, the clamp diode 221 is turned on in the reverse direction. The reverse clamp voltage of the clamp diode 221 decreases the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to the threshold value to ensure that the turn-on characteristic of the first switching transistor 21 is not affected.

[0353] When a surge occurs during wired charging or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the first gate electrode G1 controls the first switching transistor 21 to be turned off. The first end of the clamp diode 221 receives the low-level turn-off signal, and as a result, the clamp diode 221 is turned on in the forward direction. The forward clamp voltage of the clamp diode 221 decreases the potential of the first control signal after the first control signal passes through the clamp diode 221, and the potential of the substrate electrode Sub is adjusted to the potential between the first gate electrode G1 and the fixed signal terminal to ensure that the breakdown voltage characteristic of the first switching transistor 21 is not affected.

[0354] The beneficial effects of this example are the same as those of Example 1 and will not be described again in detail in this specification.

[0355] Example 3 The structure of the charging protection circuit 20 in Example 3 is different from those in Example 1 and Example 2.

[0356] As shown in FIG. 10A, the charging protection circuit 20 includes a first switching transistor 21 and a bidirectional circuit 24.

[0357] The first switching transistor 21 has a first drain electrode D1, a second drain electrode D2, a first gate electrode G1, and a substrate electrode Sub. The first drain electrode D1 is configured to receive a signal from the second drain electrode D2, the second drain electrode D2 is configured to receive a signal from the first drain electrode D1, and the first gate electrode G1 is configured to receive a first control signal and control the first switching transistor 21 to be turned on or off.

[0358] The structure of the first switching transistor 21 may be the same as that of the first switching transistor 21 in Example 1. For a description of the first switching transistor 21 in Example 1, reference is made, and details will not be described again herein.

[0359] The bidirectional circuit 24 is coupled to the first drain electrode D1, the second drain electrode D2, and the substrate electrode Sub, and when the first switching transistor 21 is controlled to be turned on, adjusts the potential of the substrate electrode Sub to the potential between the first drain electrode D1 and the second drain electrode D2, and when the first switching transistor 21 is turned off, adjusts the potential of the substrate electrode Sub to approach the lower potential of the first drain electrode D1 and the second drain electrode D2.

[0360] In other words, during normal wired charging (when the electronic device is charged), the first switching transistor 21 is turned on under the control of the first control signal received by the first gate electrode G1, and the first drain electrode D1 transmits the received power supply voltage Vsy to the second drain electrode D2 for output. Also, the bidirectional circuit 24 adjusts the potential of the substrate electrode Sub to the potential between the first drain electrode D1 and the second drain electrode D2.

[0361] During normal reverse charging (where an electronic device charges an external device), the first switching transistor 21 is turned on under the control of a first control signal received by the first gate electrode G1, and the second drain electrode D2 transmits the received discharge voltage to the first drain electrode D1 for output. Also, the bidirectional circuit 24 adjusts the potential of the substrate electrode Sub to the potential between the first drain electrode D1 and the second drain electrode D2.

[0362] The principle of normal wired charging is the same as that of normal reverse charging. Hereinafter, only normal wired charging is used as an example for explanation.

[0363] When a surge occurs during wired charging or wireless charging, the first switching transistor 21 is turned off under the control of the first control signal input to the first gate electrode G1, and the bidirectional circuit 24 adjusts the potential of the substrate electrode Sub to the lower potential of the first drain electrode D1 and the second drain electrode D2.

[0364] Regarding the structure of the bidirectional circuit 24, in some embodiments, as shown in FIG. 10B, the bidirectional circuit includes a third switching transistor SW3 and a fourth switching transistor SW4.

[0365] The third gate electrode G3 of the third switching transistor SW3 is configured to control the turning on or off of the third switching transistor SW3. The first electrode of the third switching transistor SW3 is coupled to the first drain electrode D1, and the second electrode of the third switching transistor SW3 is coupled to the substrate electrode Sub.

[0366] The fourth gate electrode G4 of the fourth switching transistor SW4 is configured to control the turning on or off of the fourth switching transistor SW4. The first electrode of the fourth switching transistor SW4 is coupled to the second drain electrode D2, and the second electrode of the fourth switching transistor SW4 is coupled to the substrate electrode Sub.

[0367] Note that the first switching transistor 21 is a bidirectional switching transistor and includes a first drain electrode D1, a second drain electrode D2, a first gate electrode G1, and a substrate electrode Sub. The third switching transistor SW3 and the fourth switching transistor SW4 are conventional switching transistors. That is, they have three terminals: a source electrode, a drain electrode, and a gate electrode. Therefore, the first electrode and the second electrode of each of the third switching transistor SW3 and the fourth switching transistor SW4 are a source electrode and a drain electrode with respect to each other. In this embodiment of the present application, unless otherwise specified, the first electrode and the second electrode of the switching transistor are the source electrode and the drain electrode of the switching transistor. Specifically, whether the first electrode is a source electrode or a drain electrode is related to the type of the switching transistor.

[0368] For example, in Example 3, the first electrode of the third switching transistor SW3 is a drain electrode, and the second electrode of the third switching transistor SW3 is a source electrode. The first electrode of the fourth switching transistor SW4 is a drain electrode, and the second electrode of the fourth switching transistor SW4 is a source electrode.

[0369] The third switching transistor SW3 and the fourth switching transistor SW4 may be MOSFET devices or HEMT devices. The third switching transistor SW3 and the fourth switching transistor SW4 may be integrated on the same substrate, or alternatively, may have a discrete structure.

[0370] In some embodiments, as shown in FIG. 10B, the third switching transistor SW3 and the fourth switching transistor SW4 are connected in series back-to-back and share a source electrode. Therefore, the structures of the third switching transistor SW3 and the fourth switching transistor SW4 are simplified.

[0371] In some embodiments, as shown in FIG. 10C, for example, the drive circuit 10 in the charging circuit 140 can output a second control signal to the third gate electrode G3, and the third gate electrode G3 controls the turning on or off of the third switching transistor SW3 based on the magnitude of the second control signal.

[0372] For example, the drive circuit 10 in the charging circuit 140 can output a second control signal to the fourth gate electrode G4, and the fourth gate electrode G4 controls the turning on or off of the fourth switching transistor SW4 based on the magnitude of the second control signal.

[0373] The third switching transistor SW3 and the fourth switching transistor SW4 are controlled to be turned on or off based on the magnitude of the second control signal. Generally, when the second control signal is higher than the threshold voltages of the third switching transistor SW3 and the fourth switching transistor SW4, the third switching transistor SW3 and the fourth switching transistor SW4 are considered to be turned on. When the second control signal is lower than the threshold voltages of the third switching transistor SW3 and the fourth switching transistor SW4, the third switching transistor SW3 and the fourth switching transistor SW4 are turned off.

[0374] In some embodiments, as shown in FIG. 10D, both the third gate electrode G3 of the third switching transistor SW3 and the fourth gate electrode G4 of the fourth switching transistor SW4 are coupled to the first gate electrode G1 of the first switching transistor 21.

[0375] That is, the first control signal and the second control signal are the same control signal, and the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are turned on and off simultaneously.

[0376] In some embodiments, as shown in FIG. 10E, the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are each HEMT devices.

[0377] The first switching transistor 21 is selected as a bidirectional HEMT device fabricated using GaN, Ga2O3, or GaAs. Compared with a bidirectional MOSFET device, the turn-on impedance of the bidirectional HEMT device can be theoretically reduced by one digit at the same breakdown voltage. In actual low-voltage applications (30 V), the turn-on impedance may also be optimized two or more times. When a 2 mm × 2 mm wafer-level chip scale package (WLCSP) is used for packaging, the turn-on impedance of the HEMT device can reach 5 ohms. In addition, the HEMT device has no parasitic diode, has a simpler structure, and has no parasitic NPN-type bipolar transistor structure. When the HEMT device is turned off, the breakdown voltage characteristics can be satisfied without reducing the potential of the substrate electrode Sub to the potential of the reference ground terminal GND.

[0378] In some embodiments, the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 share the same substrate.

[0379] For example, the manufacturing method of the charging protection circuit 20 shown in FIG. 10E has the same steps as the manufacturing method of the charging protection circuit shown in FIG. 7C. The differences are that the structure of the gate metal layer formed in step 7 is different, the structure of the source-drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0380] For example, the method of manufacturing the charging protection circuit 20 includes the following steps.

[0381] Step 1: Select a substrate.

[0382] Step 2: Form a nucleation layer on the substrate.

[0383] Step 3: Form a buffer layer on the nucleation layer.

[0384] Step 4: Form a channel layer on the buffer layer.

[0385] Step 5: Form a barrier layer on the channel layer.

[0386] Step 6: Form a p-type thin film on the barrier layer.

[0387] Step 7: Form a gate metal layer on the p-type thin film.

[0388] As shown in FIG. 10E, the gate metal layer includes the first gate electrode G1 of the first switching transistor 21, the third gate electrode G3 of the third switching transistor SW3, and the fourth gate electrode G4 of the fourth switching transistor SW4.

[0389] Step 8: By using the gate metal layer as a mask, etch the p-type thin film to form a gate cap layer.

[0390] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0391] Step 10: Form a source-drain metal layer.

[0392] As shown in FIG. 10E, the source-drain metal layer includes a first drain electrode D1, a second drain electrode D2, the first and second electrodes of a third switching transistor SW3, and the first and second electrodes of a fourth switching transistor SW4.

[0393] Step 11: Form a separation region between devices.

[0394] Step 12: Form a passivation layer.

[0395] Step 13: Form a wiring layer.

[0396] As shown in FIG. 10E, the wiring layer includes a first wiring 1 that connects a plurality of extraction points of the first drain electrode D1, a second wiring 2 that connects a plurality of extraction points of the second drain electrode D2, and a third wiring 3 that connects a plurality of extraction points of the first gate electrode G1, the third gate electrode G3, and the fourth gate electrode G4.

[0397] The charge protection circuit 20 fabricated using the above method is shown in FIG. 10E. In the bidirectional circuit 24, the third gate electrode G3 of the third switching transistor SW3 is coupled to the first gate electrode G1 of the first switching transistor 21, the first electrode of the third switching transistor SW3 is coupled to the first drain electrode D1, and the second electrode of the third switching transistor SW3 is coupled to the substrate electrode Sub. The fourth gate electrode G4 of the fourth switching transistor SW4 is coupled to the first gate electrode G1 of the first switching transistor 21, the first electrode of the fourth switching transistor SW4 is coupled to the second drain electrode D2, and the second electrode of the fourth switching transistor SW4 is coupled to the substrate electrode Sub.

[0398] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 10D, as shown in FIG. 10F, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are controlled to be turned on. The potential of the substrate electrode Sub is adjusted to the potential between the first drain electrode D1 and the second drain electrode D2 by the voltage division action of the third switching transistor SW3 and the fourth switching transistor SW4, ensuring that the turn-on characteristics of the first switching transistor 21 are not affected.

[0399] When the first switching transistor 21 is turned on, it can be understood that the resistance of the first switching transistor 21 can also be ignored. In this case, the potentials of the first drain electrode D1 and the second drain electrode D2 are equal or approximately equal. In this case, the potential of the substrate electrode Sub will be adjusted to the potential between the first drain electrode D1 and the second drain electrode D2, and it can be understood that the potential of the substrate electrode Sub follows the potentials of the first drain electrode D1 and the second drain electrode D2.

[0400] When a surge occurs during wired charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are controlled to turn off. In this case, the first drain electrode D1 becomes a high potential due to the presence of the surge, and the second drain electrode D2 becomes a lower potential than the first drain electrode D1. The voltage drop direction of the third switching transistor SW3 is from the first electrode to the second electrode (the voltage difference is large, the leakage current is large, and the turn-off impedance is small), and the voltage drop direction of the fourth switching transistor SW4 is from the second electrode to the first electrode (the voltage difference is small, the leakage current is small, and the turn-off impedance is large). Therefore, the impedance at the time of turning off the fourth switching transistor SW4 is much larger than the impedance at the time of turning off the third switching transistor SW3. Due to the voltage division action of the third switching transistor SW3 and the fourth switching transistor SW4, the potential of the substrate electrode Sub becomes almost equal to the potential of the second drain electrode D2, so the breakdown characteristics and breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0401] During wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are controlled to turn off. As shown in FIG. 10C, in this case, the second drain electrode D2 receives the power supply voltage Vsy of the wireless power supply terminal, so it is at a high potential, and the first drain electrode D1 is at a lower potential than the second drain electrode D2. The voltage drop direction of the third switching transistor SW3 is from the second electrode to the first electrode (the voltage difference is small, the leakage current is small, and the turn-off impedance is large), and the voltage drop direction of the fourth switching transistor SW4 is from the first electrode to the second electrode (the voltage difference is large, the leakage current is large, and the turn-off impedance is small). Therefore, the impedance when the third switching transistor SW3 turns off is much larger than the impedance when the fourth switching transistor SW4 turns off. Due to the voltage division effect of the third switching transistor SW3 and the fourth switching transistor SW4, the potential of the substrate electrode Sub becomes approximately equal to the potential of the first drain electrode D1, so the breakdown voltage characteristics and breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0402] The charging protection circuit 20 provided in this example is verified by using a circuit simulation tool. The circuit diagram of the simulation circuit is shown in FIG. 10G. The power supply voltage Vsy is 20V. The output voltage Vot1 output to the load by the charging protection circuit 20 rises to 20 V by using the energy storage capacitor C1 when the first switching transistor 21 is turned on. Also, the gate drive signal Vpulse is used to control the turn-on and turn-off of the first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4.

[0403] FIG. 10H shows waveforms of the output voltage Vot1 of the charge protection circuit 20 and the voltage VSub of the substrate electrode Sub when the gate drive signal Vpulse changes from 0 V to 5 V. When Vpulse = 5 V, the voltage of the first gate electrode G1 is at a higher potential than the voltage of the second drain electrode D2, the voltage of the third gate electrode G3 is at a higher potential than the voltages of the first and second electrodes of the third switching transistor SW3, and the voltage of the fourth gate electrode G4 is at a higher potential than the voltages of the first and second electrodes of the fourth switching transistor SW4. The first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are turned on, the energy storage capacitor C1 is charged, and the output voltage Vot1 = Vsy = 20 V. In addition, the voltage VSub of the substrate electrode Sub follows the voltage of the first drain electrode D1, and since the voltage of the substrate electrode Sub is close to 20 V, the turn-on characteristics of the first switching transistor 21 are not affected.

[0404] When Vpulse = 0 V, the voltage of the first gate electrode G1 is at a lower potential than the voltage of the second drain electrode D2, the voltage of the third gate electrode G3 is at a lower potential than the voltage of the second electrode of the third switching transistor SW3, and the voltage of the fourth gate electrode G4 is at a lower potential than the voltage of the second electrode of the fourth switching transistor SW4. The first switching transistor 21, the third switching transistor SW3, and the fourth switching transistor SW4 are turned off. In this case, the auxiliary resistor Rload enables the energy storage capacitor C1 to discharge, and the output voltage Vot1 gradually changes to 0 V. In addition, the voltage VSub of the substrate electrode Sub is jointly controlled by the third switching transistor SW3 and the fourth switching transistor SW4, and Vot1 is close to 0 V (VSub < 0.5 V). Therefore, when the first switching transistor 21 is turned on, VSub - VD2 is close to 0 V, and the breakdown voltage of the first switching transistor 21 is not affected.

[0405] Similarly, during wireless charging, when the first switching transistor 21 is turned off, VSub - VD1 is close to 0 V, and thus the breakdown voltage of the first switching transistor 21 is not affected.

[0406] Therefore, in this example, the charge protection circuit 20 includes a bidirectional circuit 24. The bidirectional circuit includes a transistor such as a HEMT device or a MOSFET device and is configured to adjust the potential of the substrate electrode Sub. When the first switching transistor 21 is turned on, the potential of the substrate electrode Sub is adjusted to be approximately equal to the potential of the first drain electrode D1. This can avoid the phenomenon that the turn - on resistance is deteriorated due to the back - gate effect caused by the charge accumulation of the substrate electrode Sub. When the first switching transistor 21 is turned on, the potential of the substrate electrode Sub is adjusted to be approximately equal to the lower potential of the first drain electrode D1 and the second drain electrode D2, so that the breakdown characteristics of the first switching transistor 21 are not affected at all, ensuring that the breakdown voltage characteristics of the first switching transistor 21 are not affected.

[0407] In addition, the first switching transistor 21 in this example is a single-gate bidirectional conduction device with a small cell size. The single-gate bidirectional conduction device has a smaller specific resistance compared to the dual-gate bidirectional conduction device. Also, the third switching transistor SW3 and the fourth switching transistor SW4 are used as a pull-up switch and a pull-down switch. When the first switching transistor 21 is turned on, the resistances of the third switching transistor SW3 and the fourth switching transistor SW4 are relatively small, and the potential of the substrate electrode Sub can be quickly pulled up to a high potential. When the first switching transistor 21 is turned off, the resistors of the third switching transistor SW3 and the fourth switching transistor SW4 are equal to infinity, which hardly affects the turn-off leakage current, thereby solving the problem of the turn-off leakage current when the resistors are used as a pull-up circuit and a pull-down circuit.

[0408] Example 4 The structure of the charge protection circuit 20 in Example 4 is different from those of Example 1, Example 2, and Example 3.

[0409] As shown in FIG. 11A, the charge protection circuit 20 includes a high electron mobility transistor HEMT, a pull-up circuit 22, and a pull-down circuit 23.

[0410] The HEMT includes a first drain electrode D1, a second drain electrode D2, a first gate electrode G1, and a substrate electrode Sub. The first drain electrode D1 is configured to receive a signal from the second drain electrode D2, the second drain electrode D2 is configured to receive a signal from the first drain electrode D1, and the first gate electrode G1 is configured to receive a first control signal and control the HEMT to be turned on or off.

[0411] In Example 1, the detailed structure of the HEMT may be the same as the structure in which the first switching transistor 21 is a HEMT device. For related explanations in Example 1, reference is made thereto, and details will not be described again herein.

[0412] The structure of the pull-up circuit 23 is shown in FIG. 11A. In some embodiments, the pull-up circuit 22 is configured to adjust the potential of the substrate electrode Sub to be equal to or approximately equal to the potential of the second drain electrode D2 when the HEMT is turned on.

[0413] For example, the pull-up circuit 22 includes a fifth switching transistor SW5. The fifth gate electrode G5 of the fifth switching transistor SW5 is configured to control the turn-on or turn-off of the fifth switching transistor SW5. The first electrode of the fifth switching transistor SW5 is coupled to the second drain electrode D2, and the second electrode of the fifth switching transistor SW5 is coupled to the substrate electrode Sub.

[0414] When the HEMT is turned on, the voltage drop of the HEMT is relatively small, and the potential of the first drain electrode D1 is approximately equal to the potential of the second drain electrode D2. When the voltage drop of the HEMT is ignored, the potential of the first drain electrode D1 is equal to the potential of the second drain electrode D2. When the fifth switching transistor SW5 is turned on, the voltage drop of the fifth switching transistor SW5 is relatively small, and the substrate electrode Sub is approximately equal to the potential of the second drain electrode D2 and also approximately equal to the potential of the first drain electrode D1. When the voltage drop of the fifth switching transistor SW5 is ignored, the substrate electrode Sub is equal to the potential of the second drain electrode D2 and also equal to the potential of the first drain electrode D1.

[0415] Therefore, being substantially equal to the potential of the second drain electrode D2 may be understood as that, with reference to the potential of the first drain electrode D1, potential fluctuations due to voltage drops of devices such as HEMT, the fifth switching transistor SW5, or wiring are substantially equal to the potential of the second drain electrode D2.

[0416] For example, the potentials in the range from (the potential of the first drain electrode D1 - the voltage drop of HEMT) to the potential of the first drain electrode D1 all belong to the potential that is substantially equal to the potential of the second drain electrode D2. When HEMT is turned on, it can be ensured that the turn-on characteristics of HEMT are not affected as long as the potential of the substrate electrode Sub is equal to or higher than the potential of the first drain electrode D1 or the second drain electrode D2. Therefore, when the first control signal controls HEMT to be turned on, the pull-up circuit 22 can adjust the potential of the substrate electrode Sub to the potential of the second drain electrode D2, and as a result, it can be ensured that the turn-on characteristics of HEMT are not affected.

[0417] The structure of the pull-up circuit 23 is shown in FIG. 11B. In some embodiments, the pull-up circuit 22 includes a sixth switching transistor SW6.

[0418] The sixth gate electrode G6 of the sixth switching transistor SW6 is configured to control the turn-on or turn-off of the sixth switching transistor SW6. The first electrode of the sixth switching transistor SW6 is coupled to the first drain electrode D1, and the second electrode of the sixth switching transistor SW6 is coupled to the substrate electrode Sub.

[0419] When the HEMT is turned on, the voltage drop across the HEMT is relatively small, and the potential of the first drain electrode D1 is approximately equal to the potential of the second drain electrode D2. When the voltage drop across the HEMT is ignored, the potential of the first drain electrode D1 is equal to the potential of the second drain electrode D2. When the sixth switching transistor SW6 is turned on, the voltage drop across the sixth switching transistor SW6 is relatively small, and the substrate electrode Sub is approximately equal to the potential of the first drain electrode D1 and also approximately equal to the potential of the second drain electrode D2. When the voltage drop across the sixth switching transistor SW6 is ignored, the substrate electrode Sub is equal to the potential of the first drain electrode D1 and also equal to the potential of the second drain electrode D2.

[0420] The structure of the pull-up circuit 23 is shown in FIG. 11C. In some embodiments, the pull-up circuit 22 includes a fifth switching transistor SW5 and a sixth switching transistor SW6.

[0421] The fifth gate electrode G5 of the fifth switching transistor SW5 is configured to control the turn-on or turn-off of the fifth switching transistor SW5. The first electrode of the fifth switching transistor SW5 is coupled to the second drain electrode D2, and the second electrode of the fifth switching transistor SW5 is coupled to the substrate electrode Sub. The sixth gate electrode G6 of the sixth switching transistor SW6 is configured to control the turn-on or turn-off of the sixth switching transistor SW6. The first electrode of the sixth switching transistor SW6 is coupled to the first drain electrode D1, and the second electrode of the sixth switching transistor SW6 is coupled to the substrate electrode Sub.

[0422] When the HEMT is turned on, the voltage drop of the HEMT is relatively small, and the potential of the first drain electrode D1 is approximately equal to the potential of the second drain electrode D2. When the voltage drop of the HEMT is ignored, the potential of the first drain electrode D1 is equal to the potential of the second drain electrode D2. When the fifth switching transistor SW5 and the sixth switching transistor SW6 are turned on, the voltage drops of the fifth switching transistor SW5 and the sixth switching transistor SW6 are relatively small, and the substrate electrode Sub is at a potential between the potential of the first drain electrode D1 and the potential of the second drain electrode D2. When the voltage drops of the fifth switching transistor SW5 and the sixth switching transistor SW6 are ignored, the substrate electrode Sub is equal to the potential of the first drain electrode D1 and also equal to the potential of the second drain electrode D2.

[0423] The pull-down circuit 23 is coupled to the fixed signal terminal and the substrate electrode Sub, and is configured to pull down the potential of the substrate electrode Sub to the potential of the fixed signal terminal when the HEMT is turned off.

[0424] The pull-down circuit 23 adjusts the potential of the substrate electrode Sub to the potential of the fixed signal terminal, so that when the first switching transistor 21 is turned off, the potential of the substrate electrode Sub is adjusted to a potential that can ensure the breakdown voltage characteristics of the first switching transistor 21. Therefore, in this embodiment of the present application, as long as the breakdown voltage characteristics of the first switching transistor 21 can be ensured, the potential of the signal transmitted by the fixed signal terminal is not limited.

[0425] In some embodiments, the potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode D1 and the second drain electrode D2 when the first switching transistor 21 is turned off.

[0426] Alternatively, when the first switching transistor 21 is turned off, the potential of the fixed signal terminal is equal to or lower than the potential of the first drain electrode D1, and when the first switching transistor 21 is turned off, the potential of the fixed signal terminal is equal to or lower than the potential of the second drain electrode D2. Alternatively, it can be understood that when the first switching transistor 21 is turned off, both the potential of the first drain electrode D1 and the potential of the second drain electrode D2 are greater than the potential of the fixed signal terminal.

[0427] For example, the potential of the fixed signal terminal is 0 or less. For example, the fixed signal terminal is a reference ground terminal (ground, GND). That is, the potential of the signal transmitted by the fixed signal terminal is 0. Alternatively, the potential of the signal transmitted by the fixed signal terminal is a potential less than 0. Hereinafter, an example in which the fixed signal terminal is the reference ground terminal GND is used for explanation.

[0428] In some embodiments, as shown in FIG. 11D, the first gate electrode G1 of the HEMT is coupled to the fifth gate electrode G5 of the fifth switching transistor SW5 and the sixth gate electrode G6 of the sixth switching transistor SW6.

[0429] The fifth gate electrode G5 of the fifth switching transistor SW5 and the sixth gate electrode G6 of the sixth switching transistor SW6 can receive, for example, a third control signal output by the drive circuit 10. The fifth gate electrode G5 controls the turn-on or turn-off of the fifth switching transistor SW5 based on the magnitude of the third control signal. The sixth gate electrode G6 controls the turn-on or turn-off of the sixth switching transistor SW6 based on the magnitude of the third control signal. However, if the first gate electrode G1 of the HEMT is coupled to the fifth gate electrode G5 of the fifth switching transistor SW5 and the sixth gate electrode G6 of the sixth switching transistor SW6, the first control signal and the third control signal may be the same control signal. When the drive circuit 10 outputs the first control signal to the charge protection circuit 20, the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 can be controlled, and as a result, the requirements for the drive circuit 10 can be reduced.

[0430] In some embodiments, the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 share the same substrate to improve the integration density of the charge protection circuit 20.

[0431] For example, the fifth switching transistor SW5 and the sixth switching transistor SW6 are also HEMT devices, and the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 share the same substrate. Alternatively, the fifth switching transistor SW5 and the sixth switching transistor SW6 are MOSFET devices, and the fifth switching transistor SW5 and the sixth switching transistor SW6 may be formed directly on the substrate of the HEMT device.

[0432] Of course, the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 may alternatively be in a discrete structure.

[0433] Regarding the structure of the pull-down circuit 23, in some embodiments, as shown in FIG. 12A, the pull-down circuit 23 includes a third resistor R3. The third resistor R3 is separately coupled to the substrate electrode Sub and the fixed signal terminal (e.g., the reference ground terminal GND).

[0434] In some embodiments, the resistance value of the third resistor R3 is at the kΩ to MΩ level.

[0435] As shown in FIG. 12A, the pull-up circuit 22 can include a fifth switching transistor SW5. As shown in FIG. 12B, the pull-up circuit 22 may alternatively include a sixth switching transistor SW6. As shown in FIG. 12C, the pull-up circuit 22 may alternatively include the fifth switching transistor SW5 and the sixth switching transistor SW6.

[0436] Hereinafter, an example in which the pull-up circuit 22 includes the fifth switching transistor SW5 and the sixth switching transistor SW6, and the pull-down circuit 23 includes the third resistor R3 will be used to describe the structure of the charge protection circuit 20.

[0437] For example, in Example 4, the first electrode of the fifth switching transistor SW5 is the drain electrode, and the second electrode of the fifth switching transistor SW5 is the source electrode. The first electrode of the sixth switching transistor SW6 is the drain electrode, and the second electrode of the sixth switching transistor SW6 is the source electrode.

[0438] As shown in FIG. 12D, in some embodiments, the HEMT, the fifth switching transistor SW5, the sixth switching transistor SW6, and the third resistor R3 are in an integrated structure.

[0439] For example, the fifth switching transistor SW5 and the sixth switching transistor SW6 are devices integrated with HEMT, and the third resistor R3 is an integrated resistor (for example, the sheet resistance of AlGaN / GaN is about 300 Ω / sq).

[0440] The manufacturing method of the charging protection circuit 20 shown in FIG. 12D has the same steps as the manufacturing method of the charging protection circuit shown in FIG. 7C of Example 1. The differences are that the structure of the gate metal layer formed in step 7 is different, the structure of the source-drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0441] For example, the method of manufacturing the charging protection circuit 20 includes the following steps.

[0442] Step 1: Select a substrate.

[0443] Step 2: Form a nucleation layer on the substrate.

[0444] Step 3: Form a buffer layer on the nucleation layer.

[0445] Step 4: Form a channel layer on the buffer layer.

[0446] Step 5: Form a barrier layer on the channel layer.

[0447] Step 6: Form a p-type thin film on the barrier layer.

[0448] Step 7: Form a gate metal layer on the p-type thin film.

[0449] As shown in FIG. 12D, the gate metal layer includes the first gate electrode G1 of the first switching transistor 21, the fifth gate electrode G5 of the fifth switching transistor SW5, and the sixth gate electrode G6 of the sixth switching transistor SW6.

[0450] Step 8: Etch the p-type thin film by using the gate metal layer as a mask to form a gate cap layer.

[0451] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0452] Step 10: Form a source-drain metal layer.

[0453] As shown in FIG. 12D, the source-drain metal layer includes a first drain electrode D1, a second drain electrode D2, the first and second electrodes of a fifth switching transistor SW5, the first and second electrodes of a sixth switching transistor SW6, and two metal ends of a third resistor R3.

[0454] Step 11: Form a separation region between devices.

[0455] Step 12: Form a passivation layer.

[0456] Step 13: Form a wiring layer.

[0457] As shown in FIG. 12D, the wiring layer includes a first wiring 1 that connects a plurality of lead-out points of the first drain electrode D1, a second wiring 2 that connects a plurality of lead-out points of the second drain electrode D2, a third wiring 3 that connects a plurality of lead-out points of the first gate electrode G1, the fifth gate electrode G5, and the sixth gate electrode G6, and a fourth wiring 4 that connects the substrate electrode Sub and the third resistor R3.

[0458] The charging protection circuit 20 fabricated using the above method is shown in FIG. 12D. In the pull-up circuit 22, the fifth gate electrode G5 of the fifth switching transistor SW5 is coupled to the first gate electrode G1, the first electrode of the fifth switching transistor SW5 is coupled to the second drain electrode D2, and the second electrode of the fifth switching transistor SW5 is coupled to the substrate electrode Sub. The sixth gate electrode G6 of the sixth switching transistor SW6 is coupled to the first gate electrode G1, the first electrode of the sixth switching transistor SW6 is coupled to the first drain electrode D1, and the second electrode of the sixth switching transistor SW6 is coupled to the substrate electrode Sub. The third resistor R3 in the pull-down circuit 23 is separately coupled to the substrate electrode Sub and the fixed signal terminal (for example, the reference ground terminal GND).

[0459] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 12C, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are controlled to be turned on. When the fifth switching transistor SW5 and the sixth switching transistor SW6 are turned on, the turn-on impedance of the fifth switching transistor SW5 and the sixth switching transistor SW6 is much smaller than the impedance of R3. Since the potential of the substrate electrode Sub follows the potentials of the first drain electrode D1 and the second drain electrode D2, the turn-on characteristics of the HEMT are not affected.

[0460] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are controlled to turn off. When the fifth switching transistor SW5 and the sixth switching transistor SW6 are turned off, the turn-off impedance of the fifth switching transistor SW5 and the sixth switching transistor SW6 is much larger than the impedance of R3. By adjusting the potential of the substrate electrode Sub to the potential of the fixed signal terminal, the breakdown characteristics and breakdown voltage characteristics of the HEMT are not affected.

[0461] The charging protection circuit 20 provided in this example is verified by using a circuit simulation tool. The circuit diagram of the simulation circuit is shown in FIG. 12E. The power supply voltage Vsy is 20V. The output voltage Vot1 output to the load by the charging protection circuit 20 is increased to 20 V by using the energy storage capacitor C1 when the HEMT is turned on. Also, the gate drive signal Vpulse is used to control the turn-on and turn-off of the first switching transistor 21, the fifth switching transistor SW5, and the sixth switching transistor SW6.

[0462] FIG. 12F shows waveforms of the output voltage Vot1 of the charge protection circuit 20 and the voltage VSub of the substrate electrode Sub when the gate drive signal Vpulse changes from 0 V to 5 V. When Vpulse = 5 V, the voltage of the first gate electrode G1 is at a higher potential than the voltage of the second drain electrode D2, the voltage of the fifth gate electrode G5 is at a higher potential than the voltage of the second electrode of the fifth switching transistor SW5, and the voltage of the sixth gate electrode G6 is at a higher potential than the voltage of the second electrode of the sixth switching transistor SW6. When the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are turned on, the energy storage capacitor C1 is charged, and as a result, the output voltage Vot1 = Vsy = 20 V. In addition, the voltage VSub of the substrate electrode Sub follows the voltages of the first drain electrode D1 and the second drain electrode D2, and the voltage of the substrate electrode Sub is close to 20 V. As a result, the turn-on characteristics of the first switching transistor 21 are not affected.

[0463] When Vpulse = 0 V, the voltage of the first gate electrode G1 is at a lower potential than the voltage of the second drain electrode D2, the voltage of the fifth gate electrode G5 is at a lower potential than the voltage of the second electrode of the fifth switching transistor SW5, and the voltage of the sixth gate electrode G6 is at a lower potential than the voltage of the second electrode of the sixth switching transistor SW6. The HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are turned off. In this case, the auxiliary resistor Rload enables the energy storage capacitor C1 to discharge, and the output voltage Vot1 gradually changes to 0 V. In addition, the voltage VSub of the substrate electrode Sub is jointly controlled by the fifth switching transistor SW5 and the sixth switching transistor SW6 and is close to Vot1 = 0 V. Therefore, when the HEMT is turned off, VSub - VD2 is close to 0 V, and the breakdown voltage of the HEMT is not affected.

[0464] Similarly, during wireless charging, when the HEMT is turned off, VSub - VD1 is close to 0 V, and as a result, the breakdown voltage of the HEMT is not affected.

[0465] Based on this, in the charging protection circuit 20 of this example, when the HEMT is turned on, the pull-down circuit 23 enables the substrate electrode Sub to be almost open-circuited with respect to the fixed signal terminal, and the pull-up circuit 22 enables the first drain electrode D1 and / or the second drain electrode D2 to be almost short-circuited with respect to the substrate electrode Sub, so as to adjust the potential of the substrate electrode Sub to the same potential or almost the same potential as the potential of the second drain electrode D2. Thereby, it is possible to avoid the phenomenon that the turn-on resistance deteriorates due to the back-gate effect caused by the charge accumulation of the substrate electrode Sub. The pull-down circuit 23 is coupled to the reference ground terminal GND. When the HEMT is turned off, the pull-up circuit 22 enables the first drain electrode D1 and / or the second drain electrode D2 to be almost open-circuited with respect to the substrate electrode Sub, and the pull-down circuit 23 enables the substrate electrode Sub to be almost short-circuited with respect to the fixed signal terminal, so as to adjust the potential of the substrate electrode Sub to be almost equal to the potential of the reference ground terminal GND. As a result, it is ensured that the breakdown characteristics of the HEMT are not affected at all.

[0466] In addition, a bidirectional HEMT device fabricated using GaN, Ga2O3, or GaAs is used as a switching transistor. Compared with a bidirectional MOSFET device, the turn-on impedance of the bidirectional HEMT device can be theoretically reduced by one order of magnitude at the same breakdown voltage. In actual low-voltage applications (30 V), the turn-on impedance may also be optimized two or more times. When a 2 mm×2 mm wafer level chip scale package (WLCSP) is used for packaging, the turn-on impedance of the HEMT device can reach 5 ohms. In addition, the HEMT device has no parasitic diode, has a simpler structure, and has no parasitic NPN bipolar transistor structure. When the HEMT device is turned off, the breakdown voltage characteristics can be satisfied without reducing the potential of the substrate electrode Sub to the potential of the reference ground terminal GND.

[0467] Furthermore, the pull-up circuit 22 and the pull-down circuit 23 may be integrated on the HEMT device, and as a result, the integration degree of the charge protection circuit 20 may be improved.

[0468] Example 5 The difference between Example 5 and Example 4 lies in the different structure of the pull-down circuit 23.

[0469] As shown in FIG. 13A, the charge protection circuit 20 includes a high electron mobility transistor HEMT, a pull-up circuit 22, and a pull-down circuit 23.

[0470] The structure of the high electron mobility transistor HEMT may be the same as that in Example 4. Referring to the relevant description in Example 4, the details will not be described again in this specification.

[0471] As shown in FIG. 13A, similar to Example 4, the pull-up circuit 22 may include a fifth switching transistor SW5. As shown in FIG. 13B, the pull-up circuit 22 may alternatively include a sixth switching transistor SW6. As shown in FIG. 13C, the pull-up circuit 22 may alternatively include a fifth switching transistor SW5 and a sixth switching transistor SW6.

[0472] As shown in FIGS. 13A to 13C, the pull-down circuit 23 includes a seventh switching transistor SW7. The seventh gate electrode G7 of the seventh switching transistor SW7 is configured to control the turn-on or turn-off of the seventh switching transistor SW7. The first electrode of the seventh switching transistor SW7 is coupled to the substrate electrode VSub, and the second electrode of the seventh switching transistor SW7 is coupled to the fixed signal terminal.

[0473] Hereinafter, the structure of the charge protection circuit 20 will be described using an example in which the pull-up circuit 22 includes a fifth switching transistor SW5 and a sixth switching transistor SW6, and the pull-down circuit 23 includes a seventh switching transistor SW7.

[0474] For example, in Example 5, the first electrode of the fifth switching transistor SW5 is the drain electrode, and the second electrode of the fifth switching transistor SW5 is the source electrode. The first electrode of the sixth switching transistor SW6 is the drain electrode, and the second electrode of the sixth switching transistor SW6 is the source electrode. The first electrode of the seventh switching transistor SW7 is the source electrode, and the second electrode of the seventh switching transistor SW7 is the drain electrode.

[0475] In some embodiments, as shown in FIG. 13D, the seventh gate electrode G7 of the seventh switching transistor SW7 receives the fourth control signal output by the drive circuit 10, and controls the turn-on or turn-off of the seventh switching transistor SW7 based on the magnitude of the fourth control signal. The phase of the fourth control signal and the phase of the first control signal are the high-level signal and the low-level signal of each other.

[0476] For example, the drive circuit 10 further includes an inverter. After being adjusted by the inverter, the signal output by PWM is output as the fourth control signal (having a phase opposite to that of the first control signal). The seventh gate electrode G7 of the seventh switching transistor SW7 is coupled to the inverter.

[0477] In some embodiments, the fifth switching transistor SW5, the sixth switching transistor SW6, and the seventh switching transistor SW7 may be MOSFET devices or HEMT devices.

[0478] In some embodiments, the fifth switching transistor SW5, the sixth switching transistor SW6, the seventh switching transistor SW7, and the HEMT are transistors of the same type (for example, all N-type switching transistors).

[0479] That is, if the fifth switching transistor SW5, the sixth switching transistor SW6, and the HEMT are turned on, the seventh switching transistor SW7 is turned off. When the fifth switching transistor SW5, the sixth switching transistor SW6, and the HEMT are turned off, the seventh switching transistor SW7 is turned on.

[0480] In some embodiments, the HEMT, the fifth switching transistor SW5, the sixth switching transistor SW6, and the seventh switching transistor SW7 are of a discrete structure.

[0481] As shown in FIG. 13E, in some embodiments, the HEMT, the fifth switching transistor SW5, the sixth switching transistor SW6, and the seventh switching transistor SW7 are of an integrated structure.

[0482] The fifth switching transistor SW5, the sixth switching transistor SW6, and the seventh switching transistor SW7 are, for example, devices integrated with the HEMT.

[0483] The manufacturing method of the charge protection circuit 20 shown in FIG. 13E has the same steps as the manufacturing method of the charge protection circuit shown in FIG. 7C of Example 1. The differences are that the structure of the gate metal layer formed in step 7 is different, the structure of the source-drain metal layer formed in step 10 is different, and the structure of the wiring layer formed in step 13 is also different.

[0484] For example, the method of manufacturing the charge protection circuit 20 includes the following steps.

[0485] <000162o>(It seems there is a typo here. I assume it should be and keep it as is.) Step 1: Select a substrate.

[0486] Step 2: Form a nucleation layer on the substrate.

[0487] Step 3: Form a buffer layer on the nucleation layer.

[0488] Step 4: Form a channel layer on the buffer layer.

[0489] Step 5: Form a barrier layer on the channel layer.

[0490] Step 6: Form a p-type thin film on the barrier layer.

[0491] Step 7: Form a gate metal layer on the p-type thin film.

[0492] As shown in FIG. 13E, the gate metal layer includes a first gate electrode G1 of the first switching transistor 21, a fifth gate electrode G5 of the fifth switching transistor SW5, a sixth gate electrode G6 of the sixth switching transistor SW6, and a seventh gate electrode G7 of the seventh switching transistor SW7.

[0493] Step 8: By using the gate metal layer as a mask, etch the p-type thin film to form a gate cap layer.

[0494] Step 9: Remove the epitaxial layer in some regions by deep trench etching.

[0495] Step 10: Form a source-drain metal layer.

[0496] As shown in FIG. 13E, the source-drain metal layer includes a first drain electrode D1, a second drain electrode D2, a first electrode and a second electrode of the fifth switching transistor SW5, a first electrode and a second electrode of the sixth switching transistor SW6, and a first electrode and a second electrode of the seventh switching transistor SW7.

[0497] Step 11: Form a separation region between the devices.

[0498] Step 12: Form a passivation layer.

[0499] Step 13: Form a wiring layer.

[0500] As shown in FIG. 13E, the wiring layer includes a first wiring 1 that connects a plurality of lead-out points of the first drain electrode D1, a second wiring 2 that connects a plurality of lead-out points of the second drain electrode D2, a third wiring 3 that connects a plurality of lead-out points of the first gate electrode G1, the fifth gate electrode G5, and the sixth gate electrode G6, and a fourth wiring 4 that connects the substrate electrode Sub and the first electrode of the seventh switching transistor SW7.

[0501] The charge protection circuit 20 manufactured using the above method is shown in FIG. 13E. In the pull-up circuit 22, the fifth gate electrode G5 of the fifth switching transistor SW5 is connected to the first gate electrode G1, the first electrode of the fifth switching transistor SW5 is connected to the second drain electrode D2, and the second electrode of the fifth switching transistor SW5 is connected to the substrate electrode Sub. The sixth gate electrode G6 of the sixth switching transistor SW6 is connected to the first gate electrode G1, the first electrode of the sixth switching transistor SW6 is connected to the first drain electrode D1, and the second electrode of the sixth switching transistor SW6 is connected to the substrate electrode Sub. In the pull-down circuit 23, the seventh gate electrode G7 of the seventh switching transistor SW7 is configured to receive a fourth control signal, the first electrode of the seventh switching transistor SW7 is connected to the substrate electrode VSub, and the second electrode of the seventh switching transistor SW7 is connected to a fixed signal terminal.

[0502] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 13C, as shown in FIG. 13F, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are controlled to be turned on. The fourth control signal received by the seventh gate electrode G7 of the seventh switching transistor SW7 is a low-level turn-off signal, and the seventh switching transistor SW7 is controlled to be turned off. When the fifth switching transistor SW5 and the sixth switching transistor SW6 are turned on and the seventh switching transistor SW7 is turned off, the turn-on impedance of the fifth switching transistor SW5 and the sixth switching transistor SW6 is much smaller than the turn-off impedance of the seventh switching transistor SW7. Since the potential of the substrate electrode Sub follows the potentials of the first drain electrode D1 and the second drain electrode D2, the turn-on characteristics of the HEMT are not affected.

[0503] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the HEMT, the fifth switching transistor SW5, and the sixth switching transistor SW6 are controlled to turn off. The fourth control signal received by the seventh gate electrode G7 of the seventh switching transistor SW7 is a high-level turn-on signal, and the seventh switching transistor SW7 is controlled to turn on. When the fifth switching transistor SW5 and the sixth switching transistor SW6 are turned off and the seventh switching transistor SW7 is turned on, the turn-off impedance of the fifth switching transistor SW5 and the sixth switching transistor SW6 is much larger than the turn-on impedance of the seventh switching transistor SW7. Since the potential of the substrate electrode Sub is adjusted to be approximately the potential of the fixed signal terminal, the breakdown characteristics and breakdown voltage characteristics of the HEMT are not affected.

[0504] In this example, the pull-down circuit 23 in the charging protection circuit 20 includes the seventh switching transistor SW7. When the pull-up circuit 22 is turned on, the pull-down circuit 23 is cut off. The path from the first drain electrode D1 and the second drain electrode D2 of the HEMT to the fixed voltage terminal is completely pinched off. The leakage current during the turn-on of the HEMT can be further reduced, and the loss from the substrate electrode Sub to the fixed voltage terminal during the turn-on of the HEMT is reduced.

[0505] Example 6 The difference between Example 5 and Example 4 is that the structure of the pull-down circuit 23 is different and the structure of the pull-up circuit 22 is not exactly the same.

[0506] As shown in FIG. 14A, the charging protection circuit 20 includes a high electron mobility transistor HEMT, a pull-up circuit 22, and a pull-down circuit 23.

[0507] The structure of the HEMT may be the same as that of Example 4. For related descriptions in Example 4, please refer to them. Details will not be described again in this specification.

[0508] As shown in FIG. 13A, the pull-up circuit 22 includes a fifth switching transistor SW5. The pull-down circuit 23 includes an eighth switching transistor SW8.

[0509] The fifth gate electrode G5 of the fifth switching transistor SW5 is configured to control the turn-on or turn-off of the fifth switching transistor SW5. The first electrode of the fifth switching transistor SW5 is coupled to the second drain electrode D2, and the second electrode of the fifth switching transistor SW5 is coupled to the substrate electrode Sub.

[0510] The eighth gate electrode G8 of the eighth switching transistor SW8 is configured to control the turn-on or turn-off of the eighth switching transistor SW8. The eighth gate electrode G8 of the eighth switching transistor SW8 is coupled to the fifth gate electrode G5 of the fifth switching transistor SW5. The first electrode of the eighth switching transistor SW8 is coupled to the substrate electrode Sub, and the second electrode of the eighth switching transistor SW8 is coupled to the fixed signal terminal.

[0511] The eighth switching transistor SW8 and the fifth switching transistor SW5 are an N-type switching transistor and a P-type switching transistor, respectively. The eighth switching transistor SW8 and the HEMT are of the same type of switching transistor (e.g., both are N-type switching transistors).

[0512] In FIG. 14A, only an example in which the eighth switching transistor SW8 and the HEMT are N-type switching transistors and the fifth switching transistor SW5 is a P-type switching transistor is used for illustration.

[0513] For example, in Example 6, the fifth switching transistor SW5 is a P-type switching transistor, the first electrode of the fifth switching transistor SW5 is the source electrode, and the second electrode of the fifth switching transistor SW5 is the drain electrode. The eighth switching transistor SW8 is an N-type switching transistor, the first electrode of the eighth switching transistor SW8 is the drain electrode, and the second electrode of the eighth switching transistor SW8 is the source electrode.

[0514] In some embodiments, as shown in FIG. 14B, the fifth gate electrode G5 of the fifth switching transistor SW5 and the eighth gate electrode G8 of the eighth switching transistor SW8 receive the third control signal output by the drive circuit 10, and based on the magnitude of the third control signal, control the turn-on or turn-off of the fifth switching transistor SW5 and the eighth switching transistor SW8. The phase of the third control signal and the phase of the first control signal are the high-level signal and the low-level signal of each other.

[0515] That is, when the eighth switching transistor SW8 and the HEMT are turned on, the fifth switching transistor SW5 is turned off. When the eighth switching transistor SW8 and the HEMT are turned off, the fifth switching transistor SW5 is turned on.

[0516] For example, the drive circuit 10 further includes an inverter. After being adjusted by the inverter, the signal output by PWM is output as the third control signal (having a phase opposite to that of the first control signal). The fifth gate electrode G5 of the fifth switching transistor SW5 and the eighth gate electrode G8 of the eighth switching transistor SW8 are both coupled to the inverter.

[0517] In some embodiments, the fifth switching transistor SW5 and the eighth switching transistor SW8 are MOSFET devices.

[0518] In some embodiments, the HEMT, the fifth switching transistor SW5, and the eighth switching transistor SW8 are of discrete structure.

[0519] In some embodiments, the HEMT, the fifth switching transistor SW5, and the eighth switching transistor SW8 are of integrated structure.

[0520] For example, the fifth switching transistor SW5 and the eighth switching transistor SW8 are MOSFET devices formed on the substrate of the HEMT.

[0521] Based on this, in the driving process of the charging protection circuit 20 shown in FIG. 14A, as shown in FIG. 14C, during normal wired charging, the first control signal received by the first gate electrode G1 is a high-level turn-on signal, and the HEMT is controlled to turn on. The fifth switching transistor SW5 is a P-type switching transistor. After the fifth gate electrode G5 receives a third control signal of low level with an inverse phase to the first control signal, the fifth switching transistor SW5 is turned on under the control of the low-level signal. The eighth switching transistor SW8 is an N-type switching transistor. After the eighth gate electrode G8 receives a third control signal of low level with an inverse phase to the first control signal, the eighth switching transistor SW8 is turned off under the control of the low-level third control signal. When the fifth switching transistor SW5 is turned on and the eighth switching transistor SW8 is turned off, the turn-on impedance of the fifth switching transistor SW5 is much smaller than the turn-off impedance of the eighth switching transistor SW8. Since the potential of the substrate electrode Sub follows the potentials of the first drain electrode D1 and the second drain electrode D2, the turn-on characteristics of the HEMT are not affected.

[0522] When a surge occurs during wired or wireless charging, the first control signal received by the first gate electrode G1 is a low-level turn-off signal, and the HEMT is controlled to be turned off. After the fifth gate electrode G5 of the fifth switching transistor SW5 receives a high-level third control signal that is in a reverse phase to the first control signal, the fifth switching transistor SW5 is turned off under the control of the high-level signal. After the eighth gate electrode G8 of the eighth switching transistor SW8 receives a high-level third control signal that is in a reverse phase to the first control signal, the eighth switching transistor SW8 is turned on under the control of the high-level third control signal. When the fifth switching transistor SW5 is turned off and the eighth switching transistor SW8 is turned on, the turn-off impedance of the fifth switching transistor SW5 is much larger than the turn-on impedance of the eighth switching transistor SW8. Since the potential of the substrate electrode Sub is adjusted to the potential of the almost fixed signal terminal, the breakdown characteristics and breakdown voltage characteristics of the HEMT are not affected.

[0523] In this example, in the pull-up circuit 22 and the pull-down circuit 23 in the charging protection circuit 20, MOSFET devices can be used as switching transistors to form a CMOS structure, and the pull-up circuit 22 and the pull-down circuit 23 are arranged separately from the HEMT. During the fabrication of the HEMT, since the separation between the HEMT and the fifth switching transistor SW5 and the eighth switching transistor SW8 does not need to be considered, the fabrication process of the HEMT can be simplified.

[0524] Also, the pull-down circuit 23 in the charging protection circuit 20 is coupled to the fixed signal terminal, and when the pull-up circuit 22 is turned on, the pull-down circuit 23 is cut off. The path from the first drain electrode D1 and the second drain electrode D2 of the HEMT to the fixed voltage terminal is completely pinched off. The leakage current during the turn-on of the HEMT can be further reduced, and the loss from the substrate electrode Sub to the fixed voltage terminal during the turn-on of the HEMT is reduced.

[0525] Based on this, embodiments of the present application provide the plurality of charging protection circuits 20 described above. No matter which charging protection circuit 20 is used, the HEMT is turned on during normal wired charging. The pull-up circuit 22 in the charging protection circuit 20 enables the potential of the substrate electrode Sub of the HEMT to approach the potentials (high potentials) of the first drain electrode D1 and the second drain electrode D2, avoiding the decrease in channel carrier concentration and the increase in HEMT turn-on resistance caused by the back-gate effect, and as a result, ensuring that the turn-on characteristics of the HEMT are not affected. When a surge occurs, the HEMT is turned off, and the potential of the substrate electrode Sub of the HEMT is pulled down to the potential of the second drain electrode D2 or ground (low potential) using the pull-down circuit 23 in the charging protection circuit 20. This avoids the insufficient breakdown voltage ability of the HEMT caused by the forward bias between the substrate electrode Sub and the second drain electrode D2 (or understood as insufficient breakdown voltage due to an overly high potential of the substrate electrode Sub), and overvoltage protection is performed on loads such as batteries. During non-contact charging, the HEMT is turned off, and the potential of the substrate electrode Sub of the HEMT is pulled down to the potential of the first drain electrode D1 or ground (low potential) using the pull-down circuit 23 in the charging protection circuit 20. This avoids the insufficient breakdown voltage ability of the HEMT due to the forward bias between the substrate electrode Sub and the first drain electrode D1, and prevents the wireless signal current from flowing backward to the wired power supply terminal.

[0526] In other words, the charging protection circuit 20 provided in the embodiments of the present application dynamically manages the potential of the substrate electrode Sub of the HEMT, and preferably avoids the deterioration of the impedance and breakdown voltage of the HEMT in the switching process of the HEMT.

[0527] Based on this, an embodiment of the present application further provides a chip. The chip includes the charging protection circuit 20.

[0528] Specifically, the chip provided in this embodiment of the present application includes a transistor having a bidirectional switching function and components for implementing the functions of a pull-up circuit and a pull-down circuit.

[0529] In some embodiments, the chip provided in this embodiment of the present application can be understood as a bare chip (bare die) directly disposed within an electronic device.

[0530] For example, as shown in FIGS. 7B-1 and 7B-2, FIGS. 8D-1 and 8D-2, FIG. 9B, FIGS. 9E-1 and 9E-2, FIG. 10E, FIG. 12D, and FIG. 13E, the pull-up circuit and the pull-down circuit within the charge protection circuit 20 are integrated with the HEMT, or the bidirectional circuit and the HEMT are integrated. The charge protection circuit 20 may be directly disposed within the electronic device as a bare die.

[0531] In some other embodiments, the chip provided in this embodiment of the present application may be disposed within the electronic device after being packaged.

[0532] Based on this, an embodiment of the present application further provides a package structure in which any one of the aforementioned charge protection circuits 20 is packaged. The package structure includes the aforementioned chip and a package housing, and the chip is packaged within the package housing.

[0533] The packaging technology used for the package structure is not limited to this embodiment of the present application. For example, the packaging can be completed by using a process such as a plastic packaging process or a WLCSP process.

[0534] It can be understood that the structure and material of the package housing vary according to different packaging technologies. This is not limited in this embodiment of the present application.

[0535] For example, as shown in FIG. 15A, the structure of a plurality of charge protection circuits 20 is shown. Regardless of which charge protection circuit 20 is used, the WLCSP can be used to implement device miniaturization packaging. The insulating package layer covers the front surface of the charge protection circuit 20 (the surface where the first drain electrode, the second drain electrode, and the first gate electrode are located) and the back surface (substrate) of the charge protection circuit 20 to form the package housing of the package structure. The insulating package layer covering the front surface of the charge protection circuit 20 exposes the first drain electrode, the second drain electrode, and the first gate electrode. Solder balls are provided at the corresponding positions of the first drain electrode, the second drain electrode, and the first gate electrode, and the solder balls implement the transfer with external signals.

[0536] The insulating packaging layer covering the back surface of the charge protection circuit 20 may be referred to as a back coating.

[0537] The height of the WLCSP device is about 0.5 mm (the back coating is about 0.025 μm, the thickness of the semiconductor layer including structural features such as switching transistors is about 0.3 mm, and the height of the solder ball is about 0.2 mm). The thickness of the WLCSP device is only half of the height of a plastic-packaged device. Furthermore, the heat dissipation effect of the WLCSP device is better than that of a plastic package device of the same size. For example, the thermal resistance of a WLCSP device with 25 balls and a size of 2 mm × 2 mm is about 30 °C / W, which is only half of the thermal resistance of a plastic package device of the same size.

[0538] Also, as shown in FIG. 15B, the pull-up circuit 22, the pull-down circuit 23, and the bidirectional circuit 24 are only used for functional purposes and have a very small circuit scale. Therefore, the pull-up circuit 22, the pull-down circuit 23, and the bidirectional circuit 24 may be directly integrated into a 2 mm × 2 mm WLCSP. The WLCSP may be compatible with the pins of a conventional HEMT device and has a simple structure.

[0539] Note that in some embodiments, the pull-up circuit 22 and the pull-down circuit 23 are integrated with the HEMT device, or the bidirectional circuit 24 is integrated with the HEMT device. The resulting charge protection circuit 20 may be directly applied after forming and packaging an integrated chip, or may be directly applied as a bare die.

[0540] In some other embodiments, as shown in FIG. 15C, the pull-up circuit 22 and / or the pull-down circuit 23 are arranged separately from the HEMT device. The HEMT device and the circuits within the pull-up circuit 22 and the pull-down circuit 23 that are integrated with the HEMT device form a chip (which may or may not be packaged). The circuits within the pull-up circuit 22 and the pull-down circuit 23 that are arranged separately from the HEMT device are used as an external structure, and this external structure is further packaged together with the chip, resulting in the package structure provided in this embodiment of the present application.

[0541] Of course, the pull-up circuit 22 and / or the pull-down circuit 23 may alternatively not be packaged together with the HEMT device, and only the HEMT device and the circuits integrated with the HEMT device are packaged. The circuits within the pull-up circuit 22 and the pull-down circuit 23 that are arranged separately from the HEMT device are used as an external structure disposed within an electronic device having a package structure.

[0542] In some other embodiments, the bidirectional circuit 24 is arranged separately from the HEMT device, and the HEMT device forms a chip (which may or may not be packaged). The bidirectional circuit 24 is used as an external structure that is further packaged together with the chip, resulting in the package structure provided in this embodiment of the present application.

[0543] Of course, the bidirectional circuit 24 does not necessarily need to be packaged together with the HEMT device, and only the HEMT device is packaged. The bidirectional circuit 24 is used as an external structure and is disposed within an electronic device having a package structure. FIG. 15B shows a plurality of first drain electrode D1 extraction solder balls and a plurality of second drain electrode D2 extraction solder balls, which do not indicate that the WLCSP device includes a plurality of HEMTs, but rather, it should be noted that they show a plurality of extraction points of the first drain electrode D1 and the second drain electrode D2 of the HEMT in order to simplify wiring and improve welding stability. The WLCSP device may alternatively include only one first drain electrode D1 extraction solder ball and only one second drain electrode D2 extraction solder ball. This is not limited to this embodiment of the present application.

[0544] Of course, the WLCSP packaging is merely an example and is for illustrative purposes only. The package structure provided in this embodiment of the present application may alternatively be another type of package structure.

[0545] Since the charge protection circuit 20 provided in this embodiment of the present application has a relatively high degree of integration, the volume of the package structure obtained after the charge protection circuit 20 is packaged is also relatively small.

[0546] After the foregoing package structure is applied to the electronic device provided in this embodiment of the present application, the foregoing package structure may be disposed on a printed circuit board (PCB) and is coupled to pins on the printed circuit board by using solder balls. The drive circuit 10 may be disposed on the printed circuit board and is coupled to pins on the printed circuit board by using solder balls in order to implement signal interaction between the package structure and the drive circuit 10.

[0547] As shown in FIG. 16, after the package structure is applied to the electronic device, the package structure receives a power supply voltage at the wired power supply terminal and / or the wireless power supply terminal of the electronic device, and under the control of the drive signal output by the drive circuit 10, transmits the power supply voltage to the load coupled to the package structure. Alternatively, the signal of the load is transmitted to the wired power supply terminal or the wireless power supply terminal under the control of the drive signal output by the drive circuit 10.

[0548] The foregoing description is merely a specific implementation form of the present application, but it is not intended to limit the protection scope of the present application. Any deformation or substitution within the technical scope disclosed in the present application shall be included within the protection scope of the present application. Therefore, the protection scope of the present application shall be in accordance with the protection scope of the claims.

Description of Reference Numerals

[0549] 1 First wiring, antenna 2 Second wiring, antenna 3 Third wiring 4 Fourth wiring 10 Drive circuit 11 Charge pump 12 PWM module 20 Charge protection circuit 21 First switching transistor 22 Second switching transistor 22 Pull-up circuit 23 Pull-down circuit 24 Bidirectional circuit 40 Nucleation layer 100 Electronic device 110 Processor 120 External memory interface 121 Internal memory 130 Universal serial bus interface 140 Charging circuit 141 Power management module 142 Battery 150 Mobile communication module 160 Wireless communication module 170 Audio module 170A Speaker 170B Receiver 170C Microphone 170D Headset jack 180 Sensor 190 Button 191 Motor 192 Indicator 193 Camera 194 Display 195 Subscriber identification module card interface 221 Clamp diode

Claims

1. A first switching transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode, wherein the first drain electrode is configured to receive a signal from the second drain electrode, the second drain electrode is configured to receive a signal from the first drain electrode, and the first gate electrode is configured to control turning on or off of the first switching transistor, and a first switching transistor; A pull-up circuit coupled to the first gate electrode and the substrate electrode and configured to adjust the potential of the substrate electrode to a threshold value when the first switching transistor is turned on, wherein the threshold value is any potential between half the potential of the first drain electrode and the potential of the first gate electrode, and a pull-up circuit; A pull-down circuit coupled to the substrate electrode and a fixed signal terminal and configured to adjust the potential of the substrate electrode to the potential of the fixed signal terminal or a potential between the first gate electrode and the fixed signal terminal when the first switching transistor is turned off, wherein the potential of the fixed signal terminal is equal to or lower than the lower of the potentials of the first drain electrode and the second drain electrode during turn-off of the first switching transistor, and a pull-down circuit; A charging protection circuit comprising the same.

2. The pull-up circuit includes a first resistor. The charging protection circuit according to claim 1, wherein a first end of the first resistor is coupled to the first gate electrode and a second end of the first resistor is coupled to the substrate electrode.

3. The pull-up circuit includes a clamp diode. The charging protection circuit according to claim 1, wherein a first end of the clamp diode is coupled to the first gate electrode and a second end of the clamp diode is coupled to the substrate electrode.

4. The first end of the clamp diode is an anode and the second end of the clamp diode is a cathode. The charging protection circuit according to claim 3, wherein the clamp diode is a PN diode, a Schottky barrier diode, or an equivalent diode formed by short-circuiting a source electrode and a gate electrode in a transistor.

5. The first end of the clamping diode is the cathode, and the second end of the clamping diode is the anode. The charging protection circuit according to claim 3, wherein the clamping diode is a Zener diode.

6. The charging protection circuit according to claim 3, wherein the pull-up circuit includes a plurality of clamping diodes connected in series.

7. A method for driving a charging protection circuit, the charging protection circuit comprising a first switching transistor, a pull-up circuit, and a pull-down circuit, the first switching transistor comprising a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode, the pull-up circuit being coupled to the first gate electrode and the substrate electrode, the pull-down circuit being coupled to the substrate electrode and a fixed signal terminal. The driving method of the charging protection circuit is as follows. Turning on the first switching transistor under the control of the first gate electrode, and receiving a signal from the second drain electrode by the first drain electrode or receiving a signal from the first drain electrode by the second drain electrode. After the first switching transistor is turned on, adjusting the potential of the substrate electrode to a threshold value by the pull-up circuit, the threshold value being an arbitrary potential between half of the potential of the first drain electrode and the potential of the first gate electrode. Turning off the first switching transistor under the control of the first gate electrode, and receiving a signal from the second drain electrode by the first drain electrode or receiving a signal from the first drain electrode by the second drain electrode. After the first switching transistor is turned off, adjusting the potential of the substrate electrode to the potential of the fixed signal terminal or a potential between the first gate electrode and the fixed signal terminal by the pull-down circuit, the potential of the fixed signal terminal being not higher than the lower of the potentials of the first drain electrode and the second drain electrode during the turn-off of the first switching transistor. A method for driving a charging protection circuit, including the above steps.

8. A first switching transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode, wherein the first drain electrode is configured to receive a signal from the second drain electrode, the second drain electrode is configured to receive a signal from the first drain electrode, and the first gate electrode is configured to control turning on or off of the first switching transistor. A bidirectional circuit coupled to the first drain electrode, the second drain electrode, and the substrate electrode, configured to adjust the potential of the substrate electrode to a potential between the first drain electrode and the second drain electrode when the first switching transistor is turned on, and to adjust the potential of the substrate electrode to the lower of the potentials of the first drain electrode and the second drain electrode when the first switching transistor is turned off. The charging protection circuit includes the bidirectional circuit.

9. A driving method for a charging protection circuit, the charging protection circuit including a first switching transistor and a bidirectional circuit, the first switching transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode, and the bidirectional circuit being coupled to the first drain electrode, the second drain electrode, and the substrate electrode. The driving method of the charging protection circuit includes: Turning on the first switching transistor under the control of the first gate electrode, and receiving a signal from the second drain electrode by the first drain electrode or receiving a signal from the first drain electrode by the second drain electrode. After the first switching transistor is turned on, adjusting the potential of the substrate electrode to a potential between the first drain electrode and the second drain electrode by the bidirectional circuit. Turning off the first switching transistor under the control of the first gate electrode, and after the first switching transistor is turned off, adjusting the potential of the substrate electrode to the lower of the potentials of the first drain electrode and the second drain electrode by the bidirectional circuit. A driving method for a charging protection circuit, including the above steps.

10. A high electron mobility transistor including a first drain electrode, a second drain electrode, a first gate electrode, and a substrate electrode, wherein the first drain electrode is configured to receive a signal from the second drain electrode, the second drain electrode is configured to receive a signal from the first drain electrode, and the first gate electrode is configured to control the high electron mobility transistor to turn on or turn off, the high electron mobility transistor; A pull-up circuit including a fifth switching transistor, wherein the fifth gate electrode of the fifth switching transistor is configured to control the fifth switching transistor to turn on or turn off, the first electrode of the fifth switching transistor is coupled to the second drain electrode, and the second electrode of the fifth switching transistor is coupled to the substrate electrode, the pull-up circuit; A pull-down circuit coupled to a fixed signal terminal and the substrate electrode and configured to pull down the potential of the substrate electrode to the potential of the fixed signal terminal when the high electron mobility transistor is turned off, wherein the potential of the fixed signal terminal is below the lower of the potentials of the first drain electrode and the second drain electrode, the pull-down circuit; and The high electron mobility transistor and the fifth switching transistor share the same substrate, a charge protection circuit.

11. The pull-up circuit further includes a sixth switching transistor, Both the sixth gate electrode of the sixth switching transistor and the fifth gate electrode of the fifth switching transistor are coupled to the first gate electrode, the first electrode of the sixth switching transistor is coupled to the first drain electrode, and the second electrode of the sixth switching transistor is coupled to the substrate electrode, the charge protection circuit according to claim 10.

12. A chip including the charge protection circuit according to claim 1.

13. A package structure including the chip according to claim 12 and a package housing, wherein the chip is packaged within the package housing.

14. An electronic device comprising the package structure according to claim 13, a printed circuit board, and a load, wherein the package structure is disposed on the printed circuit board and coupled to the printed circuit board, and the package structure is further coupled to the load.

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