Protection circuit, chip and electronic equipment
By designing a protection circuit including a switch isolation module and a voltage clamp module in the type-C interface, the damage problem of low-voltage devices caused by high-voltage short circuit is solved, and high-voltage isolation and reducing the risk of damage is achieved.
Patent Information
- Application Number
- CN202421056131.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-03-28
- Estimated Expiration
- 2034-05-15
AI Technical Summary
The type-C interface is prone to short circuits when using high-voltage VBUS, damaging the low-voltage MOS tubes. The existing technology lacks effective high-voltage isolation and protection measures.
Design a protection circuit, including a switch isolation module and a voltage clamping module, which is turned off when the high voltage short circuit is shorted to prevent damage to low voltage devices. The voltage clamping module of the switch isolation module is clamped at the set voltage through the voltage clamping module, disconnecting the positive feedback path, reducing the risk of damage.
High voltage isolation in high voltage short circuit situations is achieved, preventing low voltage devices from being damaged, and reducing the risk of damage to the circuit.
Smart Images
Figure CN222691378U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of electronic technology, and in particular to a protection circuit, a chip and an electronic device. Background Art
[0002] As the unified charging interface for future smart devices and personal computer device chargers, the USB (Universal Serial Bus) type-C interface plays an irreplaceable role in daily life.
[0003] In the socket and plug ends of the type-C interface, the CC (Configuration Channel) and SBU (SideBand Use) ports respectively play the role of USB-C handshake transmission protocol and control signals for transmitting non-USB data (such as DP display interface, HDMI high-definition multimedia interface control signals). The CC and SBU ports are very close to the power end VBUS (Voltage Bus), and there is a probability of short circuit when in use.
[0004] In fast charging applications, when VBUS is high voltage (such as 28V), if there is no protection measure, the low-voltage MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) of the subsequent stage will be damaged. Therefore, before the PD (Power Delivery) detection circuit, a protection circuit is required to perform high-voltage isolation. Utility Model Content
[0005] In order to solve the problems of the prior art, the embodiments of the present application provide a protection circuit, a chip and an electronic device, which can achieve high voltage isolation. The technical solution is as follows:
[0006] According to one aspect of the present application, a protection circuit is provided, the protection circuit comprising a switch isolation module and a voltage clamping module;
[0007] The control end of the switch isolation module is connected to the voltage clamping module, the output end is connected to the first circuit to be isolated, and the input end is connected to the second circuit to be isolated.
[0008] According to another aspect of the present application, a chip is provided, comprising the above protection circuit.
[0009] According to another aspect of the present application, an electronic device is provided, comprising the above protection circuit.
[0010] In the present application, the protection circuit includes a switch isolation module and a voltage clamping module, the control end of the switch isolation module is connected to the voltage clamping module, the output end is connected to the first circuit to be isolated, and the input end is connected to the second circuit to be isolated. The switch isolation module arranged between the first circuit and the second circuit can be turned off when a high-voltage short circuit occurs to prevent damage to low-voltage devices and achieve high-voltage isolation. In addition, the voltage clamping module can clamp the control end voltage of the switch isolation module to a set voltage, so that the positive feedback path that pulls up the control end voltage of the switch isolation module is disconnected, thereby reducing the risk of damaging the circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further details, features and advantages of the present application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:
[0012] Figure 1 A schematic diagram of a protection circuit provided according to an exemplary embodiment of the present application is shown;
[0013] Figure 2 A schematic diagram of a voltage clamping module provided according to an exemplary embodiment of the present application is shown;
[0014] Figure 3 A schematic diagram of another voltage clamping module provided according to an exemplary embodiment of the present application is shown;
[0015] Figure 4 Another protection circuit schematic diagram provided according to an exemplary embodiment of the present application is shown;
[0016] Figure 5 A schematic diagram of a voltage maintaining module provided according to an exemplary embodiment of the present application is shown;
[0017] Figure 6 A schematic diagram of another voltage maintaining module provided according to an exemplary embodiment of the present application is shown;
[0018] Figure 7 Another protection circuit schematic diagram provided according to an exemplary embodiment of the present application is shown;
[0019] Figure 8 Another protection circuit schematic diagram provided according to an exemplary embodiment of the present application is shown.
[0020] In the figure,
[0021] 1. Switch isolation module; 2. Voltage clamping module; 21. Clamping unit; 22. Voltage increasing unit; 3. Voltage maintaining module; 31. Switch conduction unit; 32. First current limiting unit; 4. Negative surge current limiting module; 41. Second current limiting unit; 42. Third current limiting unit; 5. Charge pump module. DETAILED DESCRIPTION
[0022] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.
[0023] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". Relevant definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc. mentioned in this application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.
[0024] It should be noted that the modifications of "one" and "plurality" mentioned in the present application are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".
[0025] The names of the messages or information exchanged between multiple devices in the embodiments of the present application are only used for illustrative purposes and are not used to limit the scope of these messages or information.
[0026] An embodiment of the present application provides a protection circuit. The protection circuit provided by the embodiment can be integrated in a chip or set in an electronic device.
[0027] like Figure 1 The protection circuit schematic diagram shown in FIG. 1 may include a switch isolation module 1 and a voltage clamp module 2. The control end of the switch isolation module 1 is connected to the voltage clamp module 2, the input end is connected to the first circuit to be isolated, and the output end is connected to the second circuit to be isolated.
[0028] The switch isolation module 1 may include a LDMOS (Laterally Diffused Metal Oxide Semiconductor) device. For the convenience of introduction, this embodiment takes a P-type LDMOS as an example for introduction.
[0029] The implementation principle is as follows:
[0030] In one possible implementation, the protection circuit provided in this embodiment can be arranged between the MCU (Microcontroller Unit) of the type-C interface (i.e., the first circuit to be isolated) and the PD detection circuit (i.e., the second circuit to be isolated) to shut down when a high-voltage short circuit occurs in the type-C interface, thereby preventing damage to low-voltage devices in the PD detection circuit and achieving high-voltage isolation.
[0031] Specifically, the output end of the switch isolation module 1 can be connected to the CC / SBU interface of the type-C to receive the input signal CC_IN of the CC interface or the input signal SBU_IN of the SBU interface; the input end can be connected to the GPIO (General-Purpose Input / Output) of the PDMCU to output the corresponding signal CC_OUT or SBU_OUT so that the PDMCU can perform PD detection. In the switch isolation module 1, the source and drain ends of the LDMOS can withstand high voltage, while the gate and source ends cannot withstand high voltage. Therefore, when the CC / SBU interface in the type-C interface is short-circuited with VBUS, the source and drain ends of the LDMOS can withstand high voltage. At the same time, due to the clamping effect of the gate-source voltage, CC_OUT / SBU_OUT is at least one threshold voltage Vth lower than the gate voltage (about 6.6V in this embodiment), ensuring that the gate-source voltage will not exceed the LDMOS withstand voltage value (about 5V), so that the LDMOS can work normally.
[0032] In the case where the voltage clamp module 2 provided in this embodiment is not provided, if the GPIO of the MCU has no backflow prevention function, when a high-voltage short circuit occurs, the CC_OUT / SBU_OUT voltage (at the beginning of the short circuit, it is one Vth less than the gate voltage, which is about less than 6V) will flow back to the GPIO power supply. In some embodiments, the control terminal voltage of the switch isolation module 1 can come from the GPIO power supply, and the control terminal voltage is pulled up, so that the CC_OUT / SBU_OUT voltage is also pulled up, and this cycle repeats, forming a positive feedback and thus damaging the circuit.
[0033] In order to solve this problem, a voltage clamping module 2 can be provided at the control end of the switch isolation module 1. The voltage clamping module 2 can generate a clamping voltage and clamp the control end voltage of the switch isolation module 1 at the voltage. In other words, the maximum value of the control end voltage of the switch isolation module 1 is the clamping voltage, so that the positive feedback path formed by the backflow of the CC_OUT / SBU_OUT voltage is disconnected, thereby reducing the risk of damaging the circuit.
[0034] Optional, such as Figure 2As shown in the schematic diagram of the voltage clamping module, the voltage clamping module 2 may include a clamping unit 21. The clamping unit 21 may be used to generate the above-mentioned clamping voltage.
[0035] Optionally, the clamping unit 21 may include a Zener diode. The reverse breakdown characteristic of the Zener diode may be used to implement signal or voltage clamping. In this embodiment, the clamping voltage of the Zener diode may be 5.75V.
[0036] Optional, such as Figure 3 As shown in the schematic diagram of the voltage clamping module, the voltage clamping module 2 may also include a voltage increasing unit 22, the first end of the voltage increasing unit 22 is connected to the control end of the switch isolation module 1, and the second end is connected to the clamping unit 21. In some possible implementations, if the clamping voltage of the clamping unit 21 does not reach the appropriate value of the control end voltage of the switch isolation module 1, the voltage increasing unit 22 may be used to increase the voltage on the basis of the clamping voltage of the clamping unit 21 as the clamping voltage of the voltage clamping module 2. Among them, the appropriate value of the control end voltage of the switch isolation module 1 is related to the control end voltage under normal working conditions, and specifically, it may be equal to or slightly greater than the control end voltage under normal working conditions, and may be set according to actual conditions. For example, under normal working conditions, if the control end voltage of the switch isolation module 1 is 6V, the clamping voltage may be greater than or equal to 6V.
[0037] Optionally, the voltage increasing unit 22 may include at least one first field effect transistor M1. The voltage value to be increased may be determined according to actual conditions, thereby determining the number of field effect transistors required and the connection relationship (such as the diode connection method). For example, if the clamping voltage of the Zener diode can be 5.75V, and the source-drain voltage of the diode-connected NMOS tube is 0.7V, then a Zener diode and a diode-connected MOS tube may be used, so that when a short circuit occurs, the gate voltage of the LDMOS is clamped at about 5.75+0.7=6.45V.
[0038] It should be noted that in actual design, attention should be paid to circuit PVT (Process Verification Test) and Monte Carlo simulation to ensure that the gate voltage can be clamped at an appropriate value on the one hand, and that the LDMOS gate will not be pulled too low during normal operation and that the impedance can meet the protocol requirements on the other hand.
[0039] Optional, such as Figure 4 As shown in the protection circuit schematic diagram, the protection circuit may further include a voltage maintaining module 3, a first end of the voltage maintaining module 3 is connected to the control end of the switch isolation module 1, and a second end of the voltage maintaining module 3 is connected to the input end of the switch isolation module.
[0040] The implementation principle is as follows:
[0041] When a high-voltage short circuit occurs, the high voltage may be coupled to the source through the source-drain capacitance of the LDMOS, causing the instantaneous gate-source voltage to far exceed the withstand voltage value, thereby damaging the LDMOS. Therefore, a voltage holding module 3 may be provided between the gate-source terminals of the LDMOS (i.e., between the control terminal and the input terminal of the switch isolation module 1) to keep the gate-source voltage of the LDMOS within the withstand voltage range, thereby reducing the risk of damaging the LDMOS.
[0042] Optional, such as Figure 5 The schematic diagram of the voltage holding module shown in FIG. 3 shows that the voltage holding module 3 includes a switch conduction unit 31. When a high-voltage short circuit occurs, the switch conduction unit 31 can be turned on, and when the source voltage of the LDMOS increases, the gate voltage also increases accordingly, so that the gate-source voltage does not exceed the allowable withstand voltage value. When the high-voltage short circuit does not occur, the switch conduction unit 31 is not turned on, and the voltage holding module 3 is also turned off, which does not affect the normal operation of the LDMOS.
[0043] Optionally, the switch conduction unit 31 may include a second field effect transistor M2. As a specific example, the second field effect transistor M2 may be a common 5V NMOS tube, whose source and gate may be connected to the gate of the LDMOS, and whose drain is connected to the source of the LDMOS.
[0044] Optional, such as Figure 6 As shown in the schematic diagram of the voltage maintaining module, the voltage maintaining module 3 also includes a first current limiting unit 32, the first end of the switch conduction unit 31 is connected to the control end of the switch isolation module 1, and the second end is connected to the first end of the first current limiting unit 32; the second end of the first current limiting unit 32 is connected to the input end of the switch isolation module 1. The first current limiting unit 32 is used to limit the current flowing through the voltage maintaining module 3 to ensure the normal operation of the switch conduction unit 31. As a specific example, the first current limiting unit 32 may include a resistor unit R1, and the resistance value of the resistor unit R1 is not limited in this embodiment. Of course, the first current limiting unit 32 may also use other impedance devices, and this embodiment does not limit the specific devices used.
[0045] Optional, such as Figure 7 As shown in the protection circuit schematic diagram, the protection circuit also includes a negative surge current limiting module 4, which may include a second current limiting unit 41, wherein the first end of the second current limiting module 41 is connected to the output end of the switch isolation module 1, and the second end is connected to the N-type buried layer in the switch isolation module 1.
[0046] The implementation principle is as follows:
[0047] In some application scenarios, a negative surge may be generated to the switch isolation module 1, such as static electricity, lightning strikes, etc., causing the parasitic PN junction of the LDMOS in the switch isolation module 1 to be turned on, causing a large current to damage the tube. In order to solve the corresponding problem, a negative surge current limiting module 4 can be set in the protection circuit. Specifically, a second current limiting unit 41 can be set at the output end of the switch isolation module 1. When a negative surge of CC_IN / SBU_IN occurs, it can be shunted by the second current limiting unit 41, thereby reducing the risk of causing a large current to damage the tube. As a specific example, the second current limiting unit 41 may include a resistor unit R2, and this embodiment does not limit the resistance value of the resistor unit R2. Of course, the second current limiting unit 41 can also use other impedance devices, and this embodiment does not limit the specific devices used.
[0048] Optionally, the negative surge current limiting module 4 may further include a third current limiting unit 42, the first end of the third current limiting unit 42 is connected to the substrate in the switch isolation module 1, and the second end is grounded. On this basis, when a negative surge of CC_OUT / SBU_OUT occurs, the third current limiting unit 42 can be used for shunting, further reducing the risk of causing large current to damage the tube. As a specific example, the third current limiting unit 42 may include a resistor unit R3, and the resistance value of the resistor unit R3 is not limited in this embodiment. Of course, the third current limiting unit 42 may also use other impedance devices, and the specific devices used in this embodiment are not limited.
[0049] Optional, such as Figure 8 As shown in the protection circuit schematic diagram, the protection circuit may further include a charge pump module 5, the output end of the charge pump module 5 is connected to the control end of the switch isolation module 1, and the input voltage of the charge pump module 5 is proportional to the input voltage of the switch isolation module.
[0050] In a possible implementation, the input voltage of the charge pump module 5 is VIN, and the charge pump module 5 can double the input voltage VIN (for example, 3.3V) and output the voltage 2VIN (for example, 6.6V), thereby minimizing the area of LDMOS while ensuring that the impedance meets the protocol conditions. If the GPIO of the PDMCU does not have an anti-backflow function, when a high-voltage short circuit occurs, the CC_OUT / SBU_OUT voltage will be backflowed to the GPIO power supply. The input voltage VIN can come from the GPIO power supply. At this time, the input voltage VIN is pulled up, which further causes the output voltage of the charge pump module 5 and the gate voltage of the LDMOS to be pulled up, so that CC_OUT / SBU_OUT is also pulled up, that is, the input voltage of the switch isolation module is also pulled up, that is, it is in a proportional relationship.
[0051] The protection circuit described above can be set in one type-C interface. When there are multiple type-C interfaces, the protection circuit can be set in each type-C interface. Compared with the overvoltage protection solution using a comparator and other technical solutions that occupy a large chip area, the protection circuit provided in this embodiment can reduce the occupied chip area and power consumption.
[0052] The embodiments of the present application can achieve the following beneficial effects:
[0053] (1) The protection circuit includes a switch isolation module and a voltage clamping module. The control end of the switch isolation module is connected to the voltage clamping module, the output end is connected to the first circuit to be isolated, and the input end is connected to the second circuit to be isolated. The switch isolation module arranged between the first circuit and the second circuit can be turned off when a high-voltage short circuit occurs to prevent damage to low-voltage devices and achieve high-voltage isolation. In addition, the voltage clamping module can clamp the control end voltage of the switch isolation module to a set voltage, so that the positive feedback path that pulls up the control end voltage of the switch isolation module is disconnected, thereby reducing the risk of damaging the circuit.
[0054] (2) The protection circuit may further include a voltage holding module to keep the voltage between the control terminal and the input terminal of the switch isolation module within a withstand voltage range, thereby reducing the risk of damaging the LDMOS.
[0055] (3) The protection circuit also includes a negative surge current limiting module. When a negative surge occurs, the negative surge current limiting module can be used for shunting, thereby reducing the risk of causing large current to damage the tube.
[0056] The exemplary embodiment of the present application also provides a chip, including the protection circuit provided by the embodiment of the present application. The protection circuit provided by the embodiment is turned off when a high-voltage short circuit occurs, thereby preventing damage to low-voltage devices and achieving high-voltage isolation. In addition, the voltage clamping module can clamp the control terminal voltage of the switch isolation module to a set voltage, so that the positive feedback path that pulls up the control terminal voltage of the switch isolation module is disconnected, thereby reducing the risk of damaging the chip.
[0057] The exemplary embodiment of the present application also provides an electronic device, including the protection circuit provided by the embodiment of the present application. The protection circuit provided by the embodiment is turned off when a high-voltage short circuit occurs, thereby preventing damage to low-voltage devices and achieving high-voltage isolation. In addition, the voltage clamping module can clamp the control terminal voltage of the switch isolation module to a set voltage, so that the positive feedback path that pulls up the control terminal voltage of the switch isolation module is disconnected, thereby reducing the risk of damaging the electronic device.
Claims
1. A protection circuit, characterized in that: The protection circuit includes a switch isolation module and a voltage clamping module; The control end of the switch isolation module is connected to the voltage clamping module, the output end is connected to the first circuit to be isolated, and the input end is connected to the second circuit to be isolated; The voltage clamping module is used to generate a clamping voltage and clamp the control terminal voltage of the switch isolation module to the clamping voltage.
2. The protection circuit according to claim 1, characterized in that: The voltage clamping module includes a clamping unit.
3. The protection circuit according to claim 2, characterized in that: The clamping unit includes a Zener diode.
4. The protection circuit according to claim 2, characterized in that: The voltage clamping module further includes a voltage increasing unit; The first end of the voltage increasing unit is connected to the control end of the switch isolation module, and the second end is connected to the clamping unit.
5. The protection circuit according to claim 4, characterized in that: The voltage increasing unit includes at least one first field effect transistor.
6. The protection circuit according to claim 1, characterized in that: The protection circuit also includes a voltage maintaining module; The first end of the voltage maintaining module is connected to the control end of the switch isolation module, and the second end is connected to the input end of the switch isolation module.
7. The protection circuit according to claim 6, characterized in that: The voltage maintaining module includes a switch conducting unit.
8. The protection circuit according to claim 7, characterized in that: The switch conduction unit includes a second field effect transistor.
9. The protection circuit according to claim 7, characterized in that: The voltage maintaining module further includes a first current limiting unit; The first end of the switch conduction unit is connected to the control end of the switch isolation module, and the second end is connected to the first end of the first current limiting unit; The second end of the first current limiting unit is connected to the input end of the switch isolation module.
10. The protection circuit according to claim 1, characterized in that: The protection circuit further includes a negative surge current limiting module, and the negative surge current limiting module includes a second current limiting unit; The first end of the second current limiting unit is connected to the output end of the switch isolation module, and the second end is connected to the N-type buried layer in the switch isolation module.
11. The protection circuit according to claim 10, characterized in that: The negative surge current limiting module also includes a third current limiting unit; The first end of the third current limiting unit is connected to the substrate in the switch isolation module, and the second end is grounded.
12. The protection circuit according to claim 1, characterized in that: The protection circuit further comprises a charge pump module, the output end of the charge pump module is connected to the control end of the switch isolation module; The input voltage of the charge pump module is directly proportional to the input terminal voltage of the switch isolation module.
13. A chip, characterized in that: The invention comprises a protection circuit as claimed in any one of claims 1 to 12.
14. An electronic device, characterized in that: The invention comprises a protection circuit as claimed in any one of claims 1 to 12.