Bidirectional semiconductor device control circuit

Abstract

The application relates to the technical field of semiconductors, and discloses a bidirectional semiconductor device control circuit, which comprises a bidirectional device, the bidirectional device being a single-gate bidirectional semiconductor device, and the bidirectional device having a substrate electrode; and a potential adjusting unit connected with the bidirectional device and used for controlling the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device to be less than or equal to a first preset voltage value when the bidirectional device is in a certain working state or is switching the working state. The application can effectively improve the dynamic performance and long-term reliability of the bidirectional device.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, specifically to a bidirectional semiconductor device control circuit. Background Technology

[0002] Due to their superior properties such as high electron mobility and high critical breakdown electric field, nitride-based wide bandgap semiconductor materials have become an ideal choice for developing high-efficiency, high-power-density power devices. Among them, gallium nitride bidirectional switches, as devices with breakdown voltage characteristics in both directions, are equivalent to two transistors connected in series in opposite directions. Compared with the scheme of using two transistors connected in series in opposite directions, bidirectional devices can significantly reduce chip area and greatly reduce chip cost. However, such bidirectional devices face a key challenge in practical applications, namely the fluctuation of substrate potential relative to the lowest potential of the bidirectional device. For example, when the substrate of the bidirectional device is in a floating state, substrate potential fluctuation is prone to occur during the switching process of the bidirectional device, which leads to an increased deviation between the substrate potential and the lowest potential of the bidirectional device, thereby affecting the dynamic performance and long-term reliability of the bidirectional device. Summary of the Invention

[0003] In view of this, this application provides a bidirectional semiconductor device control circuit to solve the aforementioned technical problems.

[0004] In a first aspect, embodiments of this application disclose a bidirectional semiconductor device control circuit, comprising:

[0005] A bidirectional device, wherein the bidirectional device is a single-gate bidirectional semiconductor device, and the bidirectional device has a substrate electrode;

[0006] A potential adjustment unit, connected to the bidirectional device, is used to control the potential difference between the substrate electrode and the lowest potential of the bidirectional device to be less than or equal to a first preset voltage value when the bidirectional device is in a certain working state or when switching working states.

[0007] In one possible example, the potential adjustment unit includes a first control device, a first diode, and a second diode. The gate of the bidirectional device is connected to the gate of the first control device. The first source of the bidirectional device is connected to the cathode of the first diode. The second source of the bidirectional device is connected to the cathode of the second diode and the drain of the first control device, respectively. The anodes of the first diode, the anodes of the second diode, and the source of the first control device are all connected to the substrate electrode.

[0008] In one possible example, the potential adjustment unit further includes a second control device, the gate of the bidirectional device is connected to the gate of the second control device, the first source of the bidirectional device is connected to the drain of the second control device, and the source of the second control device is connected to the substrate electrode.

[0009] In one possible example, the bidirectional device is in a first off state when the voltage difference applied between the gate and the second source of the bidirectional device is less than the threshold voltage of the bidirectional device, and the voltage difference between the first source and the second source of the bidirectional device is the bus voltage.

[0010] When the voltage difference applied between the gate and the second source of the bidirectional device is greater than the threshold voltage of the bidirectional device, and the voltage difference between the first source and the second source of the bidirectional device is a second preset voltage value, the bidirectional device is in a first conducting state.

[0011] In one possible example, the bidirectional device is in a second off state when the voltage difference applied between the gate and the first source of the bidirectional device is less than the threshold voltage of the bidirectional device, and the voltage difference between the second source and the first source of the bidirectional device is the bus voltage.

[0012] When the voltage difference applied between the gate and the first source of the bidirectional device is greater than the threshold voltage of the bidirectional device, and the voltage difference between the second source and the first source of the bidirectional device is a second preset voltage value, the bidirectional device is in a second conduction state.

[0013] In one possible example, a first parasitic capacitance exists between the first source of the bidirectional device and the substrate electrode, and a second parasitic capacitance exists between the second source of the bidirectional device and the substrate electrode.

[0014] In one possible example, when the bidirectional device switches from a first on state or a second on state to the first off state, the displacement current flowing through the first parasitic capacitance is adjusted to control the second diode to be in the on state, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

[0015] When the bidirectional device switches from the first off state or the second off state to the first on state, the potential of the substrate electrode is controlled by adjusting the on-resistance of the first control device, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

[0016] In one possible example, when the bidirectional device switches from a first on state or a second on state to a second off state, the displacement current flowing through the second parasitic capacitance is adjusted to control the first diode to be in the on state, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

[0017] When the bidirectional device switches from the first off state or the second off state to the second on state, the potential of the substrate electrode is controlled by adjusting the on-resistance of the first control device, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

[0018] In one possible example, when the bidirectional device is in the first conducting state, both the first control device and the second control device are in the conducting state. By adjusting the on-resistance of the first control device or controlling the second diode to be in the on state, the voltage value between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

[0019] In one possible example, the difference between the threshold voltage of the first controller and the threshold voltage of the bidirectional device is less than a third preset voltage value, and the difference between the threshold voltage of the second controller and the threshold voltage of the bidirectional device is less than the third preset voltage value.

[0020] In summary, compared with the prior art, the bidirectional semiconductor device control circuit of this application includes a bidirectional device and a potential adjustment unit. The bidirectional device is a single-gate bidirectional semiconductor device with a substrate electrode. When the bidirectional device is in a certain working state or switching working states, the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device can be controlled to be less than or equal to a first preset voltage value (a small voltage value) by adjusting the potential adjustment unit. This makes the potential of the substrate electrode basically equal to the lowest potential of the bidirectional device, thereby minimizing the deviation between the potential of the substrate electrode and the lowest potential of the bidirectional device, thus reducing the impact on the dynamic performance and long-term reliability of the bidirectional device. Therefore, this application can effectively improve the dynamic performance and long-term reliability of the bidirectional device. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the first structure of the bidirectional semiconductor device control circuit according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of a second structure of the bidirectional semiconductor device control circuit according to an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the third structure of the bidirectional semiconductor device control circuit according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the fourth structure of the bidirectional semiconductor device control circuit according to an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the fifth structure of the bidirectional semiconductor device control circuit according to an embodiment of this application;

[0027] Figure 6 This is a schematic diagram of the bidirectional device in the embodiments of this application. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the claims.

[0029] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0030] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0031] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0032] In the description of this application, it should be noted that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] The technical solutions shown in this application will be described in detail below through specific embodiments. It should be noted that the order of description of the following embodiments is not intended to limit the priority of the embodiments.

[0034] In existing technologies, for example, when the substrate electrode is in a floating state, the substrate potential is prone to fluctuation, thereby increasing the deviation between the substrate potential and the lowest potential of the bidirectional device, which affects the dynamic performance and long-term reliability of the bidirectional device. Alternatively, in existing technologies, when the substrate electrode is in a non-floating state, the relative lowest potential of the bidirectional device changes between the device electrodes depending on the operating scenario or environment. However, at this time, the potential of the substrate electrode is bound to the potential of a certain electrode of the bidirectional device or the electrode potential of an external device. Therefore, the deviation between the substrate potential and the lowest potential of the bidirectional device will change with the operating scenario or environment, affecting the dynamic performance and long-term reliability of the bidirectional device.

[0035] Based on this, this application provides a bidirectional semiconductor device control circuit, which aims to dynamically adjust the potential of the substrate electrode of the bidirectional device by means of a built-in potential adjustment unit, so as to solve the device reliability and dynamic performance problems caused by the large deviation of the substrate potential from the lowest potential of the bidirectional device in the prior art.

[0036] Please see Figures 1 to 5 The bidirectional semiconductor device control circuit of this application embodiment includes a bidirectional device T and a potential adjustment unit. The bidirectional device T is a single-gate bidirectional semiconductor device (such as a single-gate gallium nitride bidirectional semiconductor device), which has only one gate drive signal. This can greatly simplify the gate drive circuit, thereby reducing system complexity and cost.

[0037] The bidirectional device T has a substrate electrode F, and a potential adjustment unit is connected to the bidirectional device T. In one application scenario, the potential adjustment unit can be integrated with the bidirectional device T on the same substrate to save chip area and reduce cost. When the bidirectional device T is in a certain working state (such as the first off state, the second off state, the first on state, or the second on state) or when switching between working states (switching between different working states), the potential adjustment unit controls the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T to be less than or equal to a first preset voltage value.

[0038] In this embodiment, by controlling the potential of the substrate electrode F through the potential adjustment unit, the potential difference between the substrate electrode F and the lowest potential of the bidirectional device T can be controlled within a first preset voltage range, so that the potential of the substrate electrode F is basically equal to the lowest potential of the bidirectional device T. This minimizes the deviation between the potential of the substrate electrode F and the lowest potential of the bidirectional device T, and also eliminates the floating state and floating problem of the substrate electrode F. This reduces the impact on the dynamic performance and long-term reliability of the bidirectional device T. Therefore, this application can effectively improve the dynamic performance and long-term reliability of the bidirectional device T.

[0039] In this embodiment, the potential adjustment unit includes a first control device Q1, a first diode D1, and a second diode D2. The gate G of the bidirectional device T is connected to the gate of the first control device Q1. The first source S1 of the bidirectional device T is connected to the cathode of the first diode D1. The second source S2 of the bidirectional device T is connected to the cathode of the second diode D2 and the drain of the first control device Q1, respectively. The anodes of the first diode D1, the anodes of the second diode D2, and the source of the first control device Q1 are all connected to the substrate electrode F.

[0040] Since the gate G of the bidirectional device T is connected to the gate of the first control device Q1, the drive signal can be applied to both the bidirectional device T and the first control device Q1 simultaneously. Each device does not need an independent drive circuit, which simplifies the design and reduces the chip area. In addition, gate linkage can make the switching timing of the two devices consistent, preventing transient overvoltage or current surges caused by delay or voltage mismatch.

[0041] In this embodiment of the application, the bidirectional device T has four operating states: a first off state, a first on state, a second off state, and a second on state. Specifically:

[0042] In the first turn-off state, when the voltage difference between the gate G and the second source S2 of the bidirectional device T is less than the threshold voltage of the bidirectional device T, and the voltage difference between the first source S1 and the second source S2 of the bidirectional device T is the bus voltage, the bidirectional device T is in the first turn-off state. In the first turn-off state, the lowest potential of the bidirectional device T is the potential of the second source S2.

[0043] In the first conduction state, when the voltage difference between the gate G and the second source S2 of the bidirectional device T is greater than the threshold voltage of the bidirectional device T, and the voltage difference between the first source S1 and the second source S2 of the bidirectional device T is a second preset voltage value, the bidirectional device T is in the first conduction state. When the bidirectional device T is conducting, a low-resistance current path is formed inside, just like a switch is completely closed. The voltage difference between the first source S1 and the second source S2 becomes very small, close to 0, that is, the second preset voltage value is a value close to 0, such as 0.2~0.5V.

[0044] In the second turn-off state, when the voltage difference between the gate G and the first source S1 of the bidirectional device T is less than the threshold voltage of the bidirectional device T, and the voltage difference between the second source S2 and the first source S1 of the bidirectional device T is the bus voltage, the bidirectional device T is in the second turn-off state. In the second turn-off state, the lowest potential of the bidirectional device T is the potential of the first source S1.

[0045] In the second conduction state, when the voltage difference between the gate G and the first source S1 of the bidirectional device T is greater than the threshold voltage of the bidirectional device T, and the voltage difference between the second source S2 and the first source S1 of the bidirectional device T is a second preset voltage value, the bidirectional device T is in the second conduction state.

[0046] It is understandable that the bidirectional device T can be turned off using negative voltage. That is, in the first or second turn-off state, the potential of the gate G of the bidirectional device T is slightly lower than that of the second source S2 or the first source S1. In this case, the lowest potential of the bidirectional device T is also considered to be the potential of the first source S1 or the second source S2.

[0047] It is understandable that there is a first parasitic capacitance C1 between the first source S1 and the substrate electrode F of the bidirectional device T, and a second parasitic capacitance C2 between the second source S2 and the substrate electrode F of the bidirectional device T. The magnitude of the first parasitic capacitance C1 and the second parasitic capacitance C2 is determined by factors such as the area of ​​the bidirectional device T, the material and thickness of the epitaxial layer.

[0048] The first preset voltage value is a small voltage value that can be preset according to the circuit reliability, dynamic performance requirements and process capabilities. For example, the first preset voltage value can be the turn-on voltage value of the diode (such as 0.2-3V) or the conduction voltage value of the first control device Q1. In practical applications, by setting the first preset voltage value, the voltage difference between the substrate electrode F and each electrode of the bidirectional device T can be limited within a safe range, thereby extending the service life of the bidirectional device T.

[0049] In one embodiment, when the bidirectional device T switches its operating state, for example, when the bidirectional device T switches from the first on state or the second on state to the first off state, the displacement current flowing through the first parasitic capacitor C1 can be adjusted to control the second diode D2 to be in the on state, so that the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T is less than or equal to the first preset voltage value.

[0050] Please see Figure 1 Taking the bidirectional device T switching from the second on state to the first off state as an example, the specific working principle is explained. Specifically, at the instant the bidirectional device T switches from the second on state to the first off state, the voltage difference between the first source S1 and the second source S2 will increase rapidly, that is, a large voltage change rate dv / dt (positive value) will be generated. dv / dt will generate a first displacement current I1 on the first parasitic capacitance C1, I1=C1*dv / dt. I1 flows through the second diode D2 to the second source S2. At this time, the second diode D2 is in the forward conduction state. The voltage difference between the substrate electrode F and the second source S2 is the forward conduction voltage drop of the second diode D2. Since the forward conduction voltage drop of the diode is very small, usually 0.2-3V, the voltage of the substrate electrode F is basically equal to the voltage of the second source S2. That is, the potential of the substrate electrode F is basically equal to the lowest potential of the bidirectional device T (i.e., the potential of the substrate electrode F and the lowest potential of the bidirectional device T are less than or equal to the first preset voltage value).

[0051] During the switching process, the first displacement current I1 generated by the charging of the first parasitic capacitor C1 flows from the second diode D2 through the second source S2 and does not flow through the gate G of the bidirectional device T, thus not affecting the gate drive circuit. When the switching event ends (i.e., the bidirectional device T switches from the second on state to the first off state), the bidirectional device T is in the first off state, dv / dt=0, the first displacement current I1=0, and at this time the voltage drop of the second diode D2 is the diode's turn-on voltage, and the potential of the substrate electrode F is also basically equal to the potential of the second source S2.

[0052] Therefore, when the bidirectional device T switches from the second on state to the first off state, or when the bidirectional device T is in the first off state, the control and adjustment of the potential adjustment unit can keep the potential of the substrate electrode F basically equal to the lowest potential of the bidirectional device T (i.e., the potential of the second source S2), thereby minimizing the deviation between the potential of the substrate electrode F and the lowest potential of the bidirectional device T, and effectively improving the dynamic performance and long-term reliability of the bidirectional device T.

[0053] In one embodiment, when the bidirectional device T switches from a first off state or a second off state to a first on state, the potential of the substrate electrode F can be controlled by adjusting the on-resistance of the first control device Q1, so that the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T is less than or equal to a first preset voltage value.

[0054] Please see Figure 2 Taking the switching of a bidirectional device T from a first off state to a first on state as an example, the specific working principle is explained as follows: When a voltage is applied to the gate G of the bidirectional device T, such that the voltage difference between the gate G and the second source S2 is greater than the threshold voltage of the bidirectional device T, the bidirectional device T will switch from the first off state to the first on state. At the instant of switching, the voltage difference between the first source S1 and the second source S2 will drop rapidly, generating a large voltage change rate dv / dt (negative value). dv / dt will generate a second displacement current I2 on the first parasitic capacitance C1, where I2 = C1 * dv / dt. Since the substrate... The voltage of electrode F is basically equal to the voltage of the second source S2. Therefore, the voltage difference between the gate G and the substrate electrode F of the bidirectional device T is basically equal to the voltage difference between the gate G and the second source S2. When a voltage is applied to the gate G to turn on the bidirectional device T, the first control device Q1 will also be in the on state. At this time, I2 can flow from the second source S2 through the first control device Q1 to the first parasitic capacitance C1. The voltage difference between the substrate electrode F and the second source S2 is -Rds_on_Q1*I2, where Rds_on_Q1 is the on-resistance of the first control device Q1. The potential of the substrate electrode F can be controlled by controlling the on-resistance of the first control device Q1.

[0055] Preferably, Rds_on_Q1*I2<5V. When the switching event ends (i.e., the bidirectional device T switches from the first off state to the first on state), the bidirectional device T is in the first on state. At this time, dv / dt=0, the second displacement current I2=0, and the potential of the substrate electrode F and the potential of the second source S2 are equal.

[0056] Therefore, when the bidirectional device T switches from the first off state to the first on state, or when the bidirectional device T is in the first on state, the control and adjustment of the potential adjustment unit can keep the potential of the substrate electrode F basically equal to the lowest potential of the bidirectional device T (i.e., the potential of the second source S2), thereby minimizing the deviation between the potential of the substrate electrode F and the lowest potential of the bidirectional device T, and effectively improving the dynamic performance and long-term reliability of the bidirectional device T.

[0057] In one embodiment, when the bidirectional device T switches from a first on state or a second on state to a second off state, the displacement current flowing through the second parasitic capacitor C2 is adjusted to control the first diode D1 to be in the on state, so that the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T is less than or equal to the first preset voltage value.

[0058] Please see Figure 3 Taking the switching of the bidirectional device T from the first on state to the second off state as an example, the specific working principle is explained. Specifically, when the bidirectional device T switches from the first on state to the second off state, the voltage difference between the second source S2 and the first source S1 will increase rapidly, that is, a large voltage change rate dv / dt (positive value) will be generated. dv / dt will generate a third displacement current I3 on ​​the second parasitic capacitor C2, I3=C2*dv / dt. I3 flows through the first diode D1 to the first source S1. At this time, the first diode D1 is in the forward conduction state. The voltage difference between the substrate electrode F and the first source S1 is the forward conduction voltage drop of the first diode D1. Since the forward conduction voltage drop of the diode is very small, the voltage of the substrate electrode F is basically equal to the voltage of the first source S1. That is, the potential of the substrate electrode F is basically equal to the lowest potential of the bidirectional device T. During the switching process, the third displacement current I3 generated by the charging of the second parasitic capacitor C2 flows from the first diode D1 through the first source S1 and does not flow through the gate G, so it will not affect the gate drive circuit.

[0059] When the switching event ends (i.e., the bidirectional device T switches from the first on state to the second off state), and the bidirectional device T is in the second off state, dv / dt=0, the third displacement current I3=0, at this time the voltage drop of the first diode D1 is the diode's turn-on voltage, and the potential of the substrate electrode F is also basically equal to the potential of the first source S1.

[0060] Therefore, when the bidirectional device T switches from the first on state to the second off state, or when the bidirectional device T is in the second off state, the control and adjustment of the potential adjustment unit can keep the potential of the substrate electrode F basically equal to the lowest potential of the bidirectional device T (i.e., the potential of the first source S1), thereby minimizing the deviation between the potential of the substrate electrode F and the lowest potential of the bidirectional device T, and effectively improving the dynamic performance and long-term reliability of the bidirectional device T.

[0061] In one embodiment, when the bidirectional device T switches from a first off state or a second off state to a second on state, the potential of the substrate electrode F is controlled by adjusting the on-resistance of the first control device Q1, so that the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T is less than or equal to a first preset voltage value.

[0062] Please see Figure 4 Taking the switching of the bidirectional device T from the second off state to the second on state as an example, the specific working principle is explained as follows: When a voltage is applied to the gate G of the bidirectional device T, making the voltage difference between the gate G and the first source S1 greater than the threshold voltage of the bidirectional device T, the bidirectional device T will switch from the second off state to the second on state. The voltage difference between the second source S2 and the first source S1 will decrease rapidly, generating a large voltage change rate dv / dt (negative value). dv / dt will generate a fourth displacement current I4 on the second parasitic capacitance, where I4 = C2 * Since the voltage of the substrate electrode F and the voltage of the first source S1 are basically equal when the device is turned off, the voltage difference between the gate G and the substrate electrode F is basically equal to the voltage difference between the gate G and the first source S1. When the gate G is subjected to a voltage to turn on the bidirectional device T, the control device Q will also be in the on state. At this time, I4 can flow from the second source S2 through the first control device Q1 to the second parasitic capacitor C2. At this time, the voltage drop of the first diode D1 is maintained at around the diode turn-on voltage, so the potential of the substrate electrode F is basically equal to the potential of the first source S1.

[0063] When the switching event ends (i.e., the bidirectional device T switches from the second off state to the second on state), the bidirectional device T is in the second on state. At this time, dv / dt=0, the fourth displacement current I4=0, the first control device Q1 is in the on state, the first diode D1 is in the forward conduction state, and the potential of the substrate electrode F is between the potential of the first source S1 and the potential of the second source S2. Since the potential of the first source S1 and the potential of the second source S2 are basically equal in the second on state, the potential of the substrate electrode F is basically equal to the lowest potential of the bidirectional device T.

[0064] Therefore, when the bidirectional device T switches from the second off state to the second on state, or when the bidirectional device T is in the second on state, the control and adjustment of the potential adjustment unit can keep the potential of the substrate electrode F basically equal to the lowest potential of the bidirectional device T (i.e., the potential of the first source S1), thereby minimizing the deviation between the potential of the substrate electrode F and the lowest potential of the bidirectional device T, and effectively improving the dynamic performance and long-term reliability of the bidirectional device T.

[0065] Please see Figure 5 Furthermore, the potential adjustment unit also includes a second control device Q2, the gate G of the bidirectional device T is connected to the gate of the second control device Q2, the first source S1 of the bidirectional device T is connected to the drain of the second control device Q2, and the source of the second control device Q2 is connected to the substrate electrode F.

[0066] exist Figure 5 In the bidirectional semiconductor device control circuit shown, when the bidirectional device T is in the first off state or the second off state, the potential of its substrate electrode F is related to the above... Figures 1 to 4 In the embodiment, the potential of the substrate electrode F is the same when the bidirectional device T is in the first off state or the second off state.

[0067] When the bidirectional device T is in the first conducting state, both the first control device Q1 and the second control device Q2 are in the conducting state. By adjusting the on-resistance of the first control device Q1 or controlling the second diode D2 to be in the open state, the potential difference between the potential of the substrate electrode F and the lowest potential of the bidirectional device T is less than or equal to the first preset voltage value.

[0068] For details, please continue reading Figure 5 When the bidirectional device T is in the first conducting state, both the first control device Q1 and the second control device Q2 are in the conducting state. At this time, the first control device Q1 can carry the first conducting current I6. If the voltage of the substrate electrode F is lower than the turn-on voltage of the diode, the second diode D2 is in the off state. The potential difference between the substrate electrode F and the second source S2 is I6*Rds_on_Q1. When the first conducting current I6 increases, the potential difference between the substrate electrode F and the second source S2 also increases. When it increases to the point that the second diode D2 can be turned on, the second diode D2 can carry the second conducting current I5. The potential difference between the substrate electrode F and the second source S2 is the turn-on voltage of the second diode D2. Since the turn-on voltage of the second diode D2 is relatively small, the potential of the substrate electrode F is basically equal to the potential of the second source S2, which is also basically equal to the lowest potential of the bidirectional device T.

[0069] Similarly, by introducing a second control device Q2 symmetrical to the first control device Q1, when the bidirectional device T is in the second conduction state, the first diode D1 can be turned on by controlling the current flowing through the second control device Q2 and the conduction resistance of the second control device Q2. The potential difference between the substrate electrode F and the first source S1 is the turn-on voltage of the first diode D1. Since the turn-on voltage of the first diode D1 is relatively small, the potential of the substrate electrode F is basically equal to the potential of the first source S1, which means that the potential of the substrate electrode F is basically equal to the lowest potential of the bidirectional device T.

[0070] In summary, the potential adjustment unit ensures that the potential of the substrate electrode F of the bidirectional device T is essentially equal to the minimum potential of the bidirectional device T in all operating states. This solves the problem in the prior art where fluctuations in the substrate potential relative to the minimum potential of the bidirectional device affect the dynamic performance and long-term reliability of the device. Furthermore, the potential adjustment unit does not affect the gate drive circuit of the bidirectional device T, thus ensuring precise control of the gate drive circuit over the conduction and turn-off of the bidirectional device T, further improving the reliability of the bidirectional device T.

[0071] In one embodiment, the first control device Q1 is a gallium nitride HEMT, which is a gallium nitride high electron mobility transistor. It is manufactured using the same gallium nitride material system and process as the bidirectional device T, which is conducive to achieving monolithic integration of the two and ensuring good matching of threshold voltage, temperature characteristics and dynamic response, while avoiding the introduction of additional process complexity and cost.

[0072] It should be noted that the difference between the threshold voltage of the first controller Q1 and the threshold voltage of the bidirectional device T is less than the third preset voltage value, and the difference between the threshold voltage of the second controller Q2 and the threshold voltage of the bidirectional device T is less than the third preset voltage value.

[0073] For example, if the threshold voltage of the bidirectional device T is Vth, and the threshold voltage of the first control device Q1 or the threshold voltage of the second control device Q2 is Vtt, then Vtt < Vth + the third preset voltage value. Preferably, the threshold voltage of the bidirectional device T is in the range of 0.5~4V, and the third preset voltage value can be set to 2V. In this case, Vtt < Vth + 2V. This ensures that when the driving voltage applied to the gate G causes the bidirectional device T to enter the conducting state, the driving voltage can also drive the first control device Q1 to enter the conducting state, thereby forming a path between the substrate electrode F and the second source S2.

[0074] If the third preset voltage value is set too high, resulting in Vtt being too high, it may cause the bidirectional device T to enter the conduction state when the driving voltage applied to the gate G is too high, while the first control device Q1 cannot be turned on due to the threshold voltage being too high, thus failing to form a path between the substrate electrode F and the second source S2.

[0075] Preferably, the bidirectional device T has a breakdown voltage Bv1 between its first source S1 and its second source S2, and a breakdown voltage Bv2 between its second source S2 and its first source S1. Bv1 and Bv2 are essentially equal, and this symmetry can simplify device design and improve device reliability.

[0076] Preferably, the breakdown voltages of the drain and source of the first control device Q1 are matched with the breakdown voltage of the bidirectional device T, which ensures that the two devices operate under the same field strength and avoids the need for additional protection circuit design due to the difference in withstand voltage.

[0077] Please see Figure 6 This is a schematic diagram of the structure of a bidirectional device T. The bidirectional device T includes a substrate layer 101, a buffer layer 102 disposed on the substrate layer 101, a channel layer 103 disposed on the buffer layer 102, a first source S1 and a second source S2 disposed opposite to each other on the channel layer 103, a barrier layer 104 disposed on the channel layer 103 and located between the first source S1 and the second source S2, a P-type gallium nitride layer 105 disposed on the barrier layer 104, and a gate G disposed on the P-type gallium nitride layer 105.

[0078] The substrate layer 101 is provided with a substrate electrode F for providing electrical connection and mechanical support. The material of the substrate layer 101 may include, but is not limited to, silicon (Si), silicon carbide (SiC), sapphire or gallium nitride (GaN) self-supporting substrate.

[0079] A buffer layer 102 is disposed on the substrate layer 101. The buffer layer 102 is typically composed of aluminum nitride (AlN) or group III nitrides such as AlGaN with graded composition. It is used to alleviate lattice mismatch and thermal mismatch between the substrate layer 101 and the epitaxial layer above it. A channel layer 103 is disposed on the buffer layer 102. The channel layer 103 is, for example, an unintentionally doped GaN layer, used to form a conductive channel for a two-dimensional electron gas (2DEG).

[0080] The first source S1 and the second source S2 are disposed opposite to each other and form an ohmic contact with the channel layer 103. The metal system of the first source S1 and the second source S2 may include a stack of Ti / Al / Ni / Au, etc.

[0081] A barrier layer 104 is disposed on the channel layer 103 and located between the first source S1 and the second source S2. The barrier layer 104 is, for example, an AlGaN layer, which forms a heterojunction with the underlying channel layer 103, thereby inducing the generation of a two-dimensional electron gas with high mobility. A P-type gallium nitride layer 105 is disposed on the barrier layer 104. The P-type gallium nitride layer 105 can be formed by doping with acceptor impurities such as magnesium (Mg) to achieve enhancement-mode (normally off) operation and optimize the electric field distribution on the device surface.

[0082] The gate G is disposed on the P-type gallium nitride layer 105 and forms an electrical contact with the P-type layer. The metal system of the gate G may include Ni / Au, Pt, etc., to form a reliable Schottky contact or ohmic contact.

[0083] The distances between the P-type gallium nitride layer 105 and the first source S1 and the second source S2 are the same. Specifically, the distance d1 from the center of the P-type gallium nitride layer 105 to the ohmic contact edge of the first source S1 and the distance d2 from the center of the P-type gallium nitride layer 105 to the ohmic contact edge of the second source S2 are designed to be basically the same (i.e., d1≈d2). This symmetrical layout is an important physical basis for ensuring that the bidirectional device T has basically consistent electrical characteristics such as threshold voltage (Vth), on-resistance (Rds(on)) and breakdown voltage (BV) in the two current directions, thereby realizing a true bidirectional controllable switch function.

[0084] In one example, the threshold voltage of the bidirectional device T can be controlled within a reasonable range by controlling process parameters such as the doping concentration and thickness of the P-type gallium nitride layer 105 and the structure of the barrier layer 104 below the gate G.

[0085] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the core ideas of the present application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present application. Therefore, the content of this specification should not be construed as a limitation of the present application.

Claims

1. A bidirectional semiconductor device control circuit, characterized in that, include: A bidirectional device, wherein the bidirectional device is a single-gate bidirectional semiconductor device, and the bidirectional device has a substrate electrode; A potential adjustment unit, connected to the bidirectional device, is used to control the potential difference between the substrate electrode and the lowest potential of the bidirectional device to be less than or equal to a first preset voltage value when the bidirectional device is in a certain working state or when the working state is switched. The potential adjustment unit includes a first control device, a first diode, and a second diode. The gate of the bidirectional device is connected to the gate of the first control device. The first source of the bidirectional device is connected to the cathode of the first diode. The second source of the bidirectional device is connected to the cathode of the second diode and the drain of the first control device, respectively. The anodes of the first diode, the anodes of the second diode, and the source of the first control device are all connected to the substrate electrode. A first parasitic capacitance exists between the first source electrode of the bidirectional device and the substrate electrode, and a second parasitic capacitance exists between the second source electrode of the bidirectional device and the substrate electrode. When the bidirectional device switches from a first on state or a second on state to a first off state, the second diode is in the on state, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value. When the bidirectional device switches from the first off state or the second off state to the first on state, the potential of the substrate electrode is controlled by adjusting the on-resistance of the first control device, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value. When the bidirectional device switches from a first on state or a second on state to a second off state, the first diode is in the on state, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value. When the bidirectional device switches from the first off state or the second off state to the second on state, the potential of the substrate electrode is controlled by adjusting the on-resistance of the first control device, so that the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value. Wherein, the product of the on-resistance of the first control device and the displacement current generated on the first parasitic capacitance when the bidirectional device switches from the first off state or the second off state to the first on state is less than 5V.

2. The bidirectional semiconductor device control circuit as described in claim 1, characterized in that, The potential adjustment unit further includes a second control device, the gate of the bidirectional device is connected to the gate of the second control device, the first source of the bidirectional device is connected to the drain of the second control device, and the source of the second control device is connected to the substrate electrode.

3. The bidirectional semiconductor device control circuit as described in claim 1, characterized in that, When the voltage difference applied between the gate and the second source of the bidirectional device is less than the threshold voltage of the bidirectional device, and the voltage difference between the first source and the second source of the bidirectional device is the bus voltage, the bidirectional device is in the first off state. When the voltage difference applied between the gate and the second source of the bidirectional device is greater than the threshold voltage of the bidirectional device, and the voltage difference between the first source and the second source of the bidirectional device is a second preset voltage value, the bidirectional device is in the first conduction state.

4. The bidirectional semiconductor device control circuit as described in claim 3, characterized in that, When the voltage difference between the gate and the first source of the bidirectional device is less than the threshold voltage of the bidirectional device, and the voltage difference between the second source and the first source of the bidirectional device is the bus voltage, the bidirectional device is in the second off state. When the voltage difference applied between the gate and the first source of the bidirectional device is greater than the threshold voltage of the bidirectional device, and the voltage difference between the second source and the first source of the bidirectional device is a second preset voltage value, the bidirectional device is in the second conduction state.

5. The bidirectional semiconductor device control circuit as described in claim 2, characterized in that, When the bidirectional device is in the first conducting state, both the first control device and the second control device are in the conducting state. By adjusting the on-resistance of the first control device or controlling the second diode to be in the on state, the potential difference between the potential of the substrate electrode and the lowest potential of the bidirectional device is less than or equal to the first preset voltage value.

6. The bidirectional semiconductor device control circuit as described in claim 2, characterized in that, The difference between the threshold voltage of the first controller and the threshold voltage of the bidirectional device is less than a third preset voltage value, and the difference between the threshold voltage of the second controller and the threshold voltage of the bidirectional device is less than the third preset voltage value.

Images