Substrate potential stabilization circuit and bidirectional switch system

Abstract

A substrate electric potential stabilization circuit that is connected to a bidirectional switch element provided with a first main electrode, a second main electrode, and a reverse-surface electrode. The substrate electric potential stabilization circuit comprises a first switch that is serially connected to the first main electrode and the reverse-surface electrode between the first main electrode and the reverse-surface electrode, a second switch that is serially connected to the second main electrode and the reverse-surface electrode between the second main electrode and the reverse-surface electrode, and a through-current prevention circuit that prevents the first switch and the second switch from simultaneously turning on. With this substrate electric potential stabilization circuit, it is possible to prevent a through-current from flowing in the circuit.

Description

[Technical field]

[0001] The present disclosure relates to a substrate potential stabilization circuit and a bidirectional switch system using a semiconductor element. [Background technology]

[0002] Patent Document 1 discloses a conventional bidirectional semiconductor switching device. The substrate voltage control circuit includes a first connection terminal, a second connection terminal, and a substrate voltage control terminal. The substrate voltage control circuit further includes a first switch having a first source, a first drain, and a first gate, the first source being connected to the substrate voltage control terminal and the first drain being connected to the first connection terminal, and a first resistor connected between the first gate and the second connection terminal. The substrate voltage control circuit further includes a second switch having a second source, a second drain, and a second gate, the second source being connected to the substrate voltage control terminal and the second drain being connected to the second connection terminal, and a second resistor connected between the second gate and the first connection terminal.

[0003] In the substrate voltage control circuit disclosed in Patent Document 1, the substrate potential is set to the same potential as the lower potential of the two sources, which allows the bidirectional switching device to operate with stable switching characteristics and allows the bidirectional switching device to operate in such a way that the difference in switching characteristics between the two current directions is reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-117110 A Summary of the Invention

[0005] The substrate potential stabilization circuit is configured to be connected to a bidirectional switch element having a first main electrode, a second main electrode, and a back electrode. The substrate potential stabilization circuit includes a first switch connected in series between the first main electrode and the back electrode, a second switch connected in series between the second main electrode and the back electrode, and a shoot-through current prevention circuit that prevents the first switch and the second switch from being turned on simultaneously. The first switch has a first control terminal for controlling the on / off of the first switch. The second switch has a second control terminal for controlling the on / off of the second switch. The through-current prevention circuit has a first resistor connected in series to the second main electrode between the first control terminal and the second main electrode of the first switch, a second resistor connected in series to the first main electrode between the second control terminal and the first main electrode of the second switch, a first through-current prevention switch connected in series between the first control terminal and the back electrode of the first switch, and a second through-current prevention switch connected in series between the second control terminal and the back electrode of the second switch. The first through-current prevention switch has a third control terminal for controlling the on / off of the first through-current prevention switch. The second through-current prevention switch has a fourth control terminal for controlling the on / off of the second through-current prevention switch. The first control terminal of the first switch is electrically connected to the fourth control terminal of the second through-current prevention switch. The second control terminal of the second switch is electrically connected to the third control terminal of the first through-current prevention switch.

[0006] This substrate potential stabilization circuit can prevent a shoot-through current from flowing through the circuit. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 1A is a circuit diagram of a bidirectional switch system according to a first embodiment. [Figure 1B] FIG. 1B is a cross-sectional view of the bidirectional switch element of the bidirectional switch system according to the first embodiment. [Figure 2A] FIG. 2A is a diagram showing a circuit simulation result of the bidirectional switch system according to the embodiment of the present invention. [Figure 2B] FIG. 2B is an enlarged view of FIG. 2A. [Figure 2C] FIG. 2C is a diagram showing the results of a circuit simulation of the potential difference and the current flowing through the switch in the bidirectional switch system. [Diagram 3] FIG. 3 is a circuit diagram of a conventional bidirectional switch system. [Figure 4A] FIG. 4A is a diagram showing a circuit simulation result of the bidirectional switch system according to the embodiment of the present invention. [Figure 4B] FIG. 4B is an enlarged view of FIG. 4A. [Figure 4C] FIG. 4C is a diagram showing the results of a circuit simulation of the potential difference in the bidirectional switch system and the current flowing through the switch. [Diagram 5] FIG. 5 is a circuit diagram of a bidirectional switch system according to the second embodiment. [Figure 6A]FIG. 6A is a diagram showing a circuit simulation result of the bidirectional switch system according to the embodiment of the present invention. [Figure 6B] FIG. 6B is an enlarged view of FIG. 6A. [Figure 6C] FIG. 6C is a diagram showing a circuit simulation result of the potential difference and the current flowing through the switch in the bidirectional switch system according to the second embodiment. [Figure 6D] FIG. 6D is an enlarged view of FIG. 6C. [Figure 6E] FIG. 6E is an enlarged view of FIG. 6C. [Figure 7A] FIG. 7A is a circuit diagram of a bidirectional switch system according to a third embodiment. [Figure 7B] FIG. 7B is a circuit diagram of another bidirectional switch system according to the third embodiment. [Figure 8] FIG. 8 is a circuit diagram of a bidirectional switch system according to the fourth embodiment. [Figure 9A] FIG. 9A is a diagram showing a circuit simulation result of the bidirectional switch system according to the embodiment of the present invention. [Figure 9B] FIG. 9B is an enlarged view of FIG. 9A. [Figure 10] FIG. 10 is a circuit diagram of another bidirectional switch system according to the fourth embodiment. [Figure 11] FIG. 11 is a circuit diagram of a bidirectional switch system according to a modified example of the fourth embodiment. [Figure 12] FIG. 12 is a circuit diagram of a bidirectional switch system according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiments and modifications. Various modifications other than these embodiments and modifications are possible according to the design, etc., as long as they do not deviate from the technical idea of ​​the present disclosure.

[0009] (Embodiment 1) (1) Overview 1A is a circuit diagram of a bidirectional switch system 100 according to embodiment 1. The bidirectional switch system 100 includes a substrate potential stabilization circuit 1, a main bidirectional switch 2, and terminals T1 and T2.

[0010] The main bidirectional switch 2 includes a bidirectional switch element Q0. In this embodiment, the bidirectional switch element Q0 is a gallium nitride-based semiconductor element using gallium nitride (GaN).

[0011] The bidirectional switch element Q0 includes a main electrode S1, a main electrode S2, a back electrode S3, a gate terminal G1 as a control terminal, and a gate terminal G2 as a control terminal. In this embodiment, the bidirectional switch element Q0 is a dual-gate type bidirectional switch element. Terminals T1 and T2 are connected to the main electrodes S1 and S2, respectively.

[0012] With respect to ground, the voltage of the main electrode S1 is V s1 and the voltage of the main electrode S2 is V s2 and the voltage of the gate terminal G1 is V g1 and the voltage of the gate terminal G2 is V g2 The voltage V of the main electrode S1 s1 The voltage V of the gate terminal G1 with respect to g1 is the voltage V gs1 The voltage V of the main electrode S2 s2 The voltage V of the gate terminal G2 with respect to g2 is the voltage V gs2 It is.

[0013] Voltage V gs1 is higher than the threshold voltage and the voltage V gs2 When is higher than this threshold voltage, the bidirectional switch element Q0 is turned on, and electrical continuity is established between the main electrodes S1 and S2.

[0014] Voltage V gs1 is lower than this threshold voltage, and the voltage V gs2When is lower than this threshold voltage, the bidirectional switch element Q0 is turned off and cuts off both the current from the main electrode S1 to the main electrode S2 and the current from the main electrode S2 to the main electrode S1.

[0015] Voltage V gs1 is higher than this threshold voltage, and the voltage V gs2 When is lower than this threshold voltage, the bidirectional switch element Q0 becomes a diode with the main electrode S1 as the cathode and the main electrode S2 as the anode, blocking the current from the main electrode S1 to the main electrode S2 and conducting the current from the main electrode S2 to the main electrode S1.

[0016] Voltage V gs1 is lower than the threshold voltage and the voltage V gs2 is higher than the threshold voltage, the bidirectional switch element Q0 becomes a diode with the main electrode S1 as the anode and the main electrode S2 as the cathode, conducting a current from the main electrode S1 to the main electrode S2 and blocking a current from the main electrode S2 to the main electrode S1.

[0017] The bidirectional switch element Q0 is a heterojunction field effect transistor, and in this embodiment, is a dual-gate GaN-based GIT (Gate Injection Transistor) using gallium nitride in the semiconductor layer. The GIT, which is a gallium nitride-based semiconductor element, is a bidirectional GIT that has a large band gap and is normally off and has low on-resistance.

[0018] FIG. 1B is a cross-sectional view of the bidirectional switch element Q0.

[0019] The bidirectional switch element Q0 includes a semiconductor substrate 61 having a main surface 61A and a back surface 61B opposite to each other, main electrodes S1 and S2 provided on the main surface 61A of the semiconductor substrate 61, gate terminals G1 and G2 provided on the main surface 61A of the semiconductor substrate 61, and a back surface electrode S3 on the back surface 61B of the semiconductor substrate 61. The semiconductor substrate 61 includes a conductive silicon (Si) substrate 5111 having surfaces 5111A and 5111B opposite to each other, and a semiconductor laminate 5113 having a surface 5113B provided on the surface 5111A of the Si substrate 5111. The semiconductor laminate 5113 has a surface 5113A opposite to the surface 5113B. A buffer layer 5112 is provided on the surface 5111A of the Si substrate 5111 between the Si substrate 5111 and the semiconductor laminate 5113. The buffer layer 5112 includes aluminum nitride (AlN) layers and gallium nitride (GaN) layers that are alternately stacked. A surface 5111B of the Si substrate and a surface 5113A of the semiconductor stack 5113 form the back surface 61B and the main surface 61A of the semiconductor substrate 61, respectively.

[0020] The semiconductor laminate 5113 is S The semiconductor layer 5111 includes a semiconductor layer 5114 provided on a surface 5111A of the substrate 5111, and a semiconductor layer 5115 provided on the semiconductor layer 5114. In the first embodiment, the semiconductor layer 5114 is an undoped gallium nitride (GaN) layer having a thickness of about 2 μm, and the semiconductor layer 5115 is an n-type aluminum gallium nitride (AlGaN) layer having a thickness of about 20 nm.

[0021] Ohmic electrodes 5116A and 5116B are formed at a distance from each other on surface 5113A of semiconductor laminate 5113. Ohmic electrodes 5116A and 5116B are made of laminated titanium (Ti) layers and aluminum (Al) layers, and are in ohmic contact with semiconductor layer 5114, which is a channel region.

[0022] 1B, in order to reduce contact resistance, a part of the semiconductor layer 5115 is removed. Furthermore, the semiconductor layer 5114 is dug down by about 40 nm, and the ohmic electrodes 5116A and 5116B are in contact with the interface between the semiconductor layer 5114 and the semiconductor layer 5115. The ohmic electrodes 5116A and 5116B may be formed on the upper surface of the semiconductor layer 5115 without being in direct contact with the semiconductor layer 5114.

[0023] An electrode wiring 5151A made of Au and Ti is formed on the upper surface of the ohmic electrode 5116A, and the electrode wiring 5151A and the ohmic electrode 5116A are electrically connected. The ohmic electrode 5116A and the electrode wiring 5151A are in ohmic contact with the semiconductor layers 5114 and 5115 of the semiconductor substrate 61 and constitute a main electrode S1 that is an ohmic electrode that does not have a rectifying function. An electrode wiring 5151B made of Au and Ti is formed on the upper surface of the ohmic electrode 5116B, and the electrode wiring 5151B and the ohmic electrode 5116B are electrically connected. The ohmic electrode 5116B and the electrode wiring 5151B are in ohmic contact with the semiconductor layers 5114 and 5115 of the semiconductor substrate 61 and constitute a main electrode S2 that is an ohmic electrode that does not have a rectifying function.

[0024] In the region between the ohmic electrodes 5116A and 5116B on the upper surface of the semiconductor layer 5115, p-type semiconductor layers 5119A and 5119B are selectively formed at intervals from each other. A gate electrode 5118A is formed on the upper surface of the p-type semiconductor layer 5119A, and a gate electrode 5118B is formed on the upper surface of the p-type semiconductor layer 5119B. The gate electrodes 5118A and 5118B are in ohmic contact with the p-type semiconductor layers 5119A and 5119B, respectively. When the p-type semiconductor layers 5119A and 5119B are formed of a gallium nitride-based semiconductor, the crystallinity of the p-type semiconductor layers 5119A and 5119B is improved, which has the advantage of reducing defects caused by crystal defects and improving reliability.

[0025] A back electrode 5153 (S3) made of a nickel (Ni) layer, a chromium (Cr) layer, and a silver (Ag) layer is formed on a surface 5111B of the Si substrate 5111, i.e., a back surface 61B of the semiconductor substrate 61. The back electrode 5153 (S3) is in ohmic contact with the Si substrate 5111. contact is doing.

[0026] The substrate potential stabilization circuit 1 is electrically connected to a bidirectional switch element Q0 having a main electrode S1, a main electrode S2, and a back electrode S3. The substrate potential stabilization circuit 1 includes a switch Q1, a switch Q2, and a shoot-through current prevention circuit 3. The switch Q1 is connected in series between the main electrode S1 and the back electrode S3. The switch Q2 is connected in series between the main electrode S2 and the back electrode S3. The shoot-through current prevention circuit 3 prevents the switches Q1 and Q2 from being turned on at the same time.

[0027] The shoot-through current prevention circuit 3 has a shoot-through prevention switch Q11 having a gate terminal GQ11 which is a control terminal, and a shoot-through prevention switch Q21 having a gate terminal GQ21 which is a control terminal. The on-off of the shoot-through prevention switch Q11 is controlled by a voltage supplied to the gate terminal GQ11. The on-off of the shoot-through prevention switch Q21 is controlled by a voltage supplied to the gate terminal GQ21.

[0028] The switch Q1 has a gate terminal GQ1 which is a control terminal, and the switch Q2 has a gate terminal GQ2 which is a control terminal. The on / off of the switch Q1 is controlled by a voltage supplied to the gate terminal GQ1. The on / off of the switch Q2 is controlled by a voltage supplied to the gate terminal GQ2.

[0029] The switches Q1, Q2 and the feed-through prevention switches Q11, Q21 are junction gate type FETs (Field Effect Transistors). In this embodiment, the switches Q1, Q2 and the feed-through prevention switches Q11, Q21 are gallium nitride semiconductor elements, and are GITs using p-type semiconductors for the gate terminals. That is, each switch is a semiconductor element using gallium nitride. In the substrate potential stabilization circuit 1, when the switches Q1, Q2 and the feed-through prevention switches Q11, Q21 are turned on, it is necessary to apply a voltage to each gate terminal while a constant current is passed through the resistors R1, R2 and the voltage of the main electrodes S1, S2 is lowered so that the voltage of each gate terminal does not become an excessive value. Therefore, when the switches Q1, Q2 and the feed-through prevention switches Q11, Q21 are MOSFETs, it is necessary to add a protection element such as a Zener diode between the gate and source so that an excessive voltage is not applied to each gate terminal. When the switches Q1, Q2 and the feed-through prevention switches Q11, Q21 are junction gate FETs or GITs, the junction gate FETs and GITs operate like diodes with the gate terminal as the anode and the source terminal as the cathode when the gate voltage exceeds the threshold voltage, and current flows from the gate to the source, which is an advantage of eliminating the need for protective elements that are required when the switches are MOSFETs. By using the switches Q1, Q2 and the feed-through prevention switches Q11, Q21 as GITs, there is an advantage that the gate protective elements required for MOSFETs are unnecessary. In addition, the bidirectional switch element Q0 and each switch are gallium nitride-based semiconductor elements, and in this embodiment, they are formed as a monolithic circuit on the same chip, which is the semiconductor substrate 61 shown in FIG. 1B. This reduces the parasitic inductance in the monolithic circuit, improving the stabilization effect of the substrate potential.

[0030] (2) Composition The bidirectional switch system 100 according to this embodiment includes a substrate potential stabilization circuit 1 and a main bidirectional switch 2, as shown in FIG. 1A.

[0031] The substrate potential stabilization circuit 1 includes a switch Q1, a switch Q2, a resistor R1, a resistor R2, and a shoot-through current prevention circuit 3.

[0032] The switch Q1 is a transistor having a drain terminal DQ1, a source terminal SQ1, and a gate terminal GQ1 which is a control terminal. The drain terminal DQ1 is connected to the main electrode S1 which is an ohmic electrode having no rectification function. The source terminal SQ1 is connected to the back electrode S3. The switch Q1 functions as a shorting switch which connects the main electrode S1 and the back electrode S3. Specifically, the drain terminal DQ1 of the switch Q1 is connected to the main electrode S1, and the source terminal SQ1 of the switch Q1 is connected to the back electrode S3. The gate terminal GQ1 of the switch Q1 is connected to the resistor R1.

[0033] The resistor R1 is connected in series between the gate terminal GQ1 and the main electrode S2 of the switch Q1.

[0034] The switch Q2 is a transistor having a drain terminal DQ2, a source terminal SQ2, and a gate terminal GQ2 which is a control terminal. The drain terminal DQ2 is connected to the main electrode S2 which is an ohmic electrode having no rectification function. The source terminal SQ2 is connected to the back electrode S3. The switch Q2 functions as a shorting switch which connects the main electrode S2 and the back electrode S3. Specifically, the drain terminal DQ2 of the switch Q2 is connected to the main electrode S2, and the source terminal SQ2 of the switch Q2 is connected to the back electrode S3. The gate terminal GQ2 of the switch Q2 is connected to the resistor R2.

[0035] Resistor R2 is the switch Q2 A switch is connected in series between the gate terminal GQ2 and the main electrode S1. Q2 The transistor GQ2 is connected to the gate terminal GQ2 and the main electrode S1.

[0036] The through-current prevention circuit 3 includes a through-current prevention switch Q11 and a through-current prevention switch Q21. The through-current prevention switch Q11 is connected in series between the gate terminal GQ1 of the switch Q1 and the back electrode S3. Specifically, the through-current prevention switch Q11 is a transistor having a source terminal SQ11, a drain terminal DQ11, and a gate terminal GQ11 which is a control terminal. The source terminal SQ11 and the drain terminal DQ11 are controlled to be connected and disconnected by a voltage supplied to the gate terminal GQ11. In this manner, the gate terminal GQ11 controls the on / off of the through-current prevention switch Q11. The source terminal SQ11 is connected to the back electrode S3. The drain terminal DQ11 is electrically connected to the main electrode S2 which is an ohmic electrode having no rectification function via a resistor R1. The source terminal SQ11 of the through-current prevention switch Q11 is connected to the back electrode S3. The drain terminal DQ11 of the through-current prevention switch Q11 is connected to the gate terminal GQ1 of the switch Q1. The gate terminal GQ11 of the feed-through prevention switch Q11 is connected to the gate terminal GQ2 of the switch Q2.

[0037] The through-hole prevention switch Q21 is connected in series between the gate terminal GQ2 and the back electrode S3 of the switch Q2. Specifically, the through-hole prevention switch Q21 is a transistor having a source terminal SQ21, a drain terminal DQ21, and a gate terminal GQ11 which is a control terminal. The source terminal SQ21 is connected to the back electrode S3. The drain terminal DQ21 is electrically connected to the main electrode S1 which is an ohmic electrode having no rectification function via a resistor R2. The voltage supplied to the gate terminal GQ21 controls the on / off of the source terminal SQ21 and the drain terminal DQ21. In this way, the gate terminal GQ21 controls the on / off of the through-hole prevention switch Q21. The source terminal SQ21 of the through-hole prevention switch Q21 is connected to the back electrode S3. The drain terminal DQ21 of the through-hole prevention switch Q21 is connected to the gate terminal GQ2 of the switch Q2. The gate terminal GQ21 of the through-hole prevention switch Q21 is connected to the gate terminal GQ1 of the switch Q1.

[0038] (3) Operation Since the gate terminal GQ1 of the switch Q1 is connected to the gate terminal GQ21 of the shoot-through prevention switch Q21, when the switch Q1 is in the on state, the gate voltage V GQ1 By 、 The penetration prevention switch Q21 is turned on. but When the switch is turned on, the rear electrode S3 is shorted to the gate terminal GQ2 of the switch Q2, so that the switch Q2 is turned off.

[0039] At this time, the gate terminal GQ2 of the switch Q2 is shorted to the back electrode S3 by the feedthrough prevention switch Q21, so the gate voltage V GQ2 is stable. Thus, the switch Q1 is on and the switch Q2 is off, and the switches Q1 and Q2 have different states.

[0040] Since the gate terminal GQ2 is connected to the gate terminal GQ11 of the shoot-through prevention switch Q11, when the switch Q2 is in the on state, the gate voltage V GQ2 , the through-hole prevention switch Q11 is turned on. When the through-hole prevention switch Q11 is turned on, the back electrode S3 is shorted to the gate terminal GQ1 of the switch Q1, so that the switch Q1 is turned off. In this way, the switch Q1 is in the off state, and the switch Q2 is in the on state, and the switches Q1 and Q2 are in different states.

[0041] At this time, the gate terminal GQ1 of the switch Q1 is shorted to the back electrode S3 by the feedthrough prevention switch Q11, so the gate voltage V GQ1 is stable.

[0042] When the switches Q1 and Q2 are both in the off state, the through-hole prevention switches Q11 and Q21 are both in the off state.

[0043] In the substrate potential stabilization circuit 1 of this embodiment, the shoot-through current prevention circuit 3 is configured to prevent the switches Q1 and Q2 from being turned on at the same time.

[0044] 2A to 2C show the results of a circuit simulation of the above operation of the substrate potential stabilization circuit 1. In FIG. 2A to FIG. 2C, the line W1 indicates the gate voltage V GQ1 The line W2 indicates the gate voltage V of the switch Q2. GQ2 2A, line W3 indicates the current flowing through switch Q1, and line W4 indicates the voltage difference between main electrodes S1 and S2. In FIG. 2A, a pulse voltage P11 is applied as pseudo noise to the gate terminal GQ1 of switch Q1 (line W1), and a rectangular voltage is applied to the gate terminal GQ2 of switch Q2. FIG. 2B shows an enlarged view of region Z1 in FIG. 2A when pulse voltage P11 is applied. As shown in FIG. 2B, even if pulse voltage P11 is applied as pseudo noise to the gate terminal GQ1 of switch Q1, the instantaneous gate voltage V GQ1 As shown in FIG. 2C, the difference between the voltage V between the main electrodes S1 and S2 is s1s2 (Line W4) maintains a predetermined voltage, which in FIG. 2C is a rectangular voltage of 400V.

[0045] For this reason, by providing the shoot-through current prevention circuit 3, false ignition is suppressed, and a shoot-through current that flows through the switches Q1 and Q2 due to the switches Q1 and Q2 being simultaneously turned on is prevented.

[0046] As a result, the switch Q1 and the feed-through prevention switch Q21 turn on at the same time, or the switch Q2 and the feed-through prevention switch Q11 turn on at the same time, which suppresses erroneous firing of the switch Q2 relative to the switch Q1, or the switch Q1 relative to the switch Q2, and prevents the switches Q1 and Q2 from turning on at the same time.

[0047] The substrate voltage control circuit disclosed in Patent Document 1 sets the substrate potential to be equal to the lower potential of the two sources. This substrate potential stabilization circuit is composed of two shorting switches that short the substrate potential and the source on the lower potential side. If these are turned on simultaneously due to erroneous firing, a shoot-through current will occur, which may cause element destruction or damage to the external system.

[0048] In contrast, in the substrate potential stabilization circuit 1 of this embodiment, as described above, the switches Q1 and Q2 are prevented from being turned on simultaneously.

[0049] (4) Comparative Example In bidirectional switches, which are gallium nitride semiconductor devices, fluctuations in the substrate potential exacerbate current collapse, which occurs when a high drain voltage is applied and the on-resistance between the two source electrodes increases compared to when a low drain voltage is applied.

[0050] 3 is a circuit diagram of the bidirectional switch system 100a. The bidirectional switch system 100a includes a substrate potential stabilization circuit 4 of a comparative example that sets the substrate potential of the bidirectional switch element Q01 to the same potential as the lower potential of the two source terminals. The substrate potential stabilization circuit 4 is composed of two shorting switches that short the back electrode and the source on the lower potential side. In the bidirectional switch system 100a, the main bidirectional switch 21 includes the bidirectional switch element Q01 as a semiconductor element. The bidirectional switch element Q01 includes a main electrode S11, a main electrode S21, a back electrode S31, a control terminal G11, and a control terminal G21. The substrate potential stabilization circuit 4 further includes gate resistors R11 and R12, a switch Q3, and a switch Q4.

[0051] The switch Q3 is a transistor having a drain terminal DQ3 connected to an ohmic electrode having no rectification function, a source terminal SQ3 connected to the rear electrode S31, and a gate terminal GQ3 which is a control terminal. The switch Q3 functions as a short-circuit switch connecting the main electrode S21 and the rear electrode S31. Specifically, the drain terminal DQ3 of the switch Q3 is connected to the main electrode S21, and the source terminal SQ3 of the switch Q3 is connected to the rear electrode S31.

[0052] The switch Q4 is a transistor having a drain terminal DQ4 connected to an ohmic electrode having no rectification function, a source terminal SQ4 connected to a rear electrode S31, and a gate terminal GQ4 which is a control terminal. The switch Q4 functions as a short-circuit switch connecting the main electrode S11 and the rear electrode S31. Specifically, the drain terminal DQ4 of the switch Q4 is connected to the main electrode S11, and the source terminal SQ4 of the switch Q4 is connected to the rear electrode S31.

[0053] A gate resistor R11 is connected to the main electrode S21 and to the gate terminal GQ4 of the switch Q4.

[0054] A gate resistor R12 is connected to the main electrode S11 and to the gate terminal GQ3 of the switch Q3.

[0055] The operation of the bidirectional switch system 100a will be described below. In the bidirectional switch system 100a shown in Fig. 3, when the main electrode S11 of the main electrodes S11 and S21, for example the main electrode S11, is at a higher potential than the main electrode S21, the potential of the main electrode S11 on the higher potential side is utilized to short the back surface electrode S3 with the main electrode S21 on the lower potential side from the OFF state of the bidirectional switch element Q01 until the voltage of the gate terminal GQ3 of the switch Q3 falls below the threshold due to the turn-on operation, thereby suppressing the fluctuation of the substrate potential.

[0056] When the switch Q3 is in an on state, the current from the main electrode S11 on the high potential side is blocked to a sufficiently low value by the gate resistor R12, which has a sufficiently large resistance value, and the switch Q3. At this time, the switch Q4 is in an off state, which is a state that does not cause a problem if the switch Q4 operates normally. In this state, for example, if noise or the like enters the switch Q4 and the switch Q4 changes from the off state to the on state for a short time, a through current flows through the switches Q3 and Q4 from the main electrode S11 on the high potential side to the main electrode S21 on the low potential side. On the other hand, even if the switch Q4 is in an on state and the switch Q3 is in an off state, a through current also flows through the switches Q3 and Q4 when noise enters the switch Q3. In other words, in the substrate potential stabilization circuit 4 shown in FIG. 3, the switches Q3 and Q4 operate independently of each other, so there is a risk that the switches Q3 and Q4 will be simultaneously turned on due to noise or the like.

[0057] The results of a circuit simulation of the bidirectional switch system 100a are shown in FIGS. 4A to 4C. In FIGS. 4A to 4C, the line W5 represents the gate voltage V GQ4 and line W6 indicates the gate voltage V of switch Q3. GQ3 and line W7 indicates the current I Q4 The line W8 indicates the voltage difference V between the main electrodes S11 and S21. s11s21 In FIG. 4A, the gate voltage V GQ4 When a pulse voltage P21 is applied to (line W5) at time t21, a current I Q4 (Line W7) fluctuates significantly from 0 A. An enlarged view of region Z2 in FIG. 4A is shown in FIG. 4B. As shown in FIG. 4B, after the application of pulse voltage P21, the current I Q4 (Line W7) returns to 0 A over a predetermined time T21 from time t21. Also, the gate voltage V GQ3 A temporary drop occurs in the line W6. Also, the potential V s11 and the potential V of the main electrode S21 s21 potential difference V s11s21 (wire W8) and current I Q4 The graph of (line W7) is shown in FIG. 4C. In the simulation, the potential difference V s11s21When a pulse voltage is applied to the switch Q4 for a 400V square wave, the current I drops instantaneously. The switches Q3 and Q4 are both turned on instantaneously, and the current I Q4 is increasing instantaneously.

[0058] (5) Advantages In the substrate potential stabilization circuit 1 including the switches Q1 and Q2, the introduction of the shoot-through prevention switches Q11 and Q21 of the shoot-through current prevention circuit 3 makes it possible to suppress the occurrence of shoot-through current flowing through the switches Q1 and Q2 in the substrate potential stabilization circuit 1. Specifically, by connecting the gate terminal GQ1 to the gate terminal GQ21 and connecting the gate terminal GQ2 to the gate terminal GQ11, the drives of the switches Q1 and Q2 can be linked in a complementary manner. This makes it possible to prevent the switches Q1 and Q2 from being turned on at the same time.

[0059] (6) Variations Below is a list of modified examples of the substrate potential stabilization circuit 1. The modified examples described below can be applied in appropriate combination with the above-described embodiment.

[0060] The bidirectional switch element Q0 is a dual-gate bidirectional switch element, but is not limited to this configuration. Even if the bidirectional switch element Q0 is a single-gate bidirectional switch, the effect of the substrate potential stabilization circuit 1 is effective.

[0061] The bidirectional switch element Q0 is configured to be a gallium nitride-based semiconductor element, but is not limited to this configuration. The bidirectional switch element Q0 of this embodiment can operate even if it is made of a semiconductor material other than gallium nitride, such as silicon or silicon carbide.

[0062] The semiconductor layers 5114 and 5115 of the bidirectional switch element Q0 are configured to be made of gallium nitride, but are not limited to this configuration. The substrate potential stabilization circuit 1 of this embodiment can operate if the semiconductor layers 5114 and 5115 are made of semiconductor materials other than gallium nitride, such as silicon and silicon carbide.

[0063] The semiconductor element of the bidirectional switch element Q0, the switch Q1, the switch Q2, the feed-through prevention switch Q11, and the feed-through prevention switch Q21 are gallium nitride semiconductor elements and are configured as a monolithic circuit on the same chip, but are not limited to this configuration. The substrate potential stabilization circuit 1 can operate even if it is not configured on a one-chip.

[0064] The switches Q1, Q2, and the feed-through prevention switches Q11 and Q21 are configured as GITs (Gate Injection Transistors) using gallium nitride semiconductor elements, but are not limited to this configuration. They may be HEMTs (High Electron Mobility Transistors) using gallium nitride semiconductor elements, silicon-based MOS (metal-oxide-semiconductor) FETs, or the like.

[0065] (Embodiment 2) 5 is a circuit diagram of a bidirectional switch system 100b according to embodiment 2. This embodiment differs from embodiment 1 in that it includes a rectifying element, a diode D1, a rectifying element, a resistor R3, and a resistor R4. Note that the same components as those in embodiment 1 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0066] In the bidirectional switch system 100 according to the first embodiment, the switch Q1 and the anti-piercing switch Q21 are turned on at the same time, and the switch Q2 and the anti-piercing switch Q11 are turned on at the same time. In the bidirectional switch system 100b according to the second embodiment, in order to further reduce the risk that the switches Q1 and Q2 are turned on at the same time, the anti-piercing switch Q11 and the anti-piercing switch Q21 are turned on before the switches Q1 and Q2 and turned off afterwards. With this configuration, for example, when the anti-piercing switch Q11 is in the on state, the risk can be further reduced by switching the switch Q2 between the on state and the off state.

[0067] The bidirectional switch system 100b further includes a diode D1, a diode D2, a resistor R3, and a resistor R4 in addition to the bidirectional switch system 100 of the first embodiment. That is, the substrate potential stabilization circuit 5 of this embodiment includes a switch Q1, a switch Q2, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a shoot-through current prevention circuit 3. The differences between the substrate potential stabilization circuit 1 of the first embodiment and the substrate potential stabilization circuit 5 of this embodiment will be described below.

[0068] The resistor R3 is connected in series between the gate terminal GQ1 of the switch Q1 and the gate terminal GQ21 of the feed-through prevention switch Q21. That is, the gate terminal GQ1 of the switch Q1 is electrically connected to the gate terminal GQ21 of the feed-through prevention switch Q21 via the resistor R3. The resistor R4 is connected in series between the gate terminal GQ2 of the switch Q2 and the gate terminal GQ11 of the feed-through prevention switch Q11. That is, the gate terminal GQ2 of the switch Q2 is electrically connected to the gate terminal GQ11 of the feed-through prevention switch Q11 via the resistor R4.

[0069] The diode D1 is connected with the forward direction being from the gate terminal GQ1 to the main electrode S2. Specifically, the anode of the diode D1 is connected to the gate terminal GQ1, and the cathode of the diode D1 is connected to the main electrode S2. The diode D2 is connected with the forward direction being from the gate terminal GQ2 to the main electrode S1. Specifically, the anode of the diode D2 is connected to the gate terminal GQ2, and the cathode of the diode D2 is connected to the main electrode S1.

[0070] Next, the circuit operation of the bidirectional switch system 100b will be described. Figures 6A to 6E show the results of a circuit simulation of the bidirectional switch system 100b. In Figures 6A and 6B, the line W9 indicates the gate voltage V GQ1 and line W10 indicates the gate voltage V of switch Q2. GQ2 The line W11 indicates the current I Q1 As shown in FIG. 6A, when the switch Q2 is on and the switch Q1 is off, a pulse voltage P31 is applied as pseudo noise to the gate terminal GQ1 of the switch Q1 (line W9). FIG. 6B shows an enlarged view of the region Z3 in FIG. 6A. In FIG. 6B, even if the pulse voltage P31 is applied, the gate voltage V GQ2 and the current I flowing through switch Q1 Q1 There is no change in (line W11), and the same effect as in the first embodiment is obtained.

[0071] In FIG. 6C to FIG. 6E, the line W10 represents the gate voltage V GQ2 The line W12 indicates the gate voltage V of the shoot-through prevention switch Q11. GQ11 The gate voltage V of switch Q2 is GQ2 and the gate voltage V of the shoot-through prevention switch Q11 GQ11 The gate voltage V of the switch Q2 is shown in FIG. GQ2 and the gate voltage V of the shoot-through prevention switch Q11 GQ11is a value where the switches Q11 and Q2 are turned on and off at almost the same time. Figure 6D shows an enlarged view of region Z4 in Figure 6C, which shows when the switches Q11 and Q2 are turned on. Figure 6E shows an enlarged view of region Z5 in Figure 6C, which shows when the switches Q11 and Q2 are turned off.

[0072] When the voltages of the gate terminals GQ1, GQ2, GQ11, and GQ21 are changed to turn on and off the switches Q1 and Q2 and the feed-through prevention switches Q11 and Q21, the capacitances of the gate terminals GQ1, GQ2, GQ11, and GQ21 are charged and discharged, so the switches Q1 and Q2 and the feed-through prevention switches Q11 and Q21 are turned on and off as described below. When the bidirectional switch element Q0 is turned off, the voltage V of the main electrode S1, which is set to 0 V as the reference voltage of the main electrode S2, is S1S2 When the voltage V of the main electrode S1 increases from 0V, the current path passing through resistors R2 and R4 from the main electrode S1 to the gate terminal GQ2 of the switch Q2 has a higher resistance than the current path passing through resistor R2 to the gate terminal GQ11 of the anti-shoot-through switch Q11. This is because resistor R4 is introduced as a gate resistor. For this reason, when both switch Q2 and anti-shoot-through switch Q11 are turned on, as shown in FIG. 6D, the anti-shoot-through switch Q11 turns on before switch Q2. Next, the bidirectional switch element Q0 turns on, and the voltage V of the main electrode S1 with respect to the main electrode S2 increases. S1S2 The following explains the case when the voltage drops to 0 V. The voltage drops from the gate terminal GQ2 of the switch Q2 to the main electrode via the diode D2. S1 The current path to the main electrode passes through the gate terminal GQ11 of the shoot-through prevention switch Q11, the diode D2, and the resistor R4. S1 The resistance of the current path to the gate is smaller than that to the gate. This is because resistor R4 is introduced as a gate resistor. Therefore, when both switch Q2 and the shoot-through prevention switch Q11 are turned off, as shown in FIG 6E, the shoot-through prevention switch Q11 is turned off after switch Q2.

[0073] The same is true for the relationship between the switch Q1 and the feed-through prevention switch Q21. When the bidirectional switch element Q0 is turned off, the voltage V of the main electrode S2 with respect to the main electrode S1 isS2S1 When rises from 0V, the current path passing through resistors R1 and R3 from the main electrode S2 to the gate terminal GQ1 of the switch Q1 has a higher resistance than the current path passing through resistor R1 to the gate terminal GQ21 of the anti-shoot-through switch Q21. This is because resistor R3 is introduced as a gate resistor. For this reason, when both switch Q1 and anti-shoot-through switch Q21 are turned on, the anti-shoot-through switch Q21 turns on before switch Q1. When the bidirectional switch element Q0 is turned on, the voltage of the main electrode S2 with respect to the main electrode S1 becomes VS2S1 When the voltage drops to 0V, the current path from the gate terminal GQ1 of the switch Q1 to the main electrode S2 via the diode D1 has a smaller resistance than the current path from the gate terminal GQ21 of the anti-shoot-through switch Q21 to the main electrode S2 via the diode D1 and resistor R3. This is because resistor R3 is introduced as a gate resistance. For this reason, when both the switch Q1 and the anti-shoot-through switch Q21 turn off, the anti-shoot-through switch Q21 turns off later than the switch Q1.

[0074] As described above, compared to the switches Q1 and Q2, the feed-through prevention switches Q11 and Q21 turn on earlier and turn off later. Therefore, the risk of the switches Q1 and Q2 turning on simultaneously in the substrate potential stabilization circuit 5 is further reduced compared to the substrate potential stabilization circuit 1 of embodiment 1. In other words, the noise resistance of the substrate potential stabilization circuit 5 is strengthened compared to the substrate potential stabilization circuit 1 of embodiment 1.

[0075] (Modification) The following are examples of modified examples. The modified examples described below can be applied in appropriate combination with the above-described embodiments.

[0076] The resistor R3 is connected in series between the gate terminal GQ21 of the feed-through prevention switch Q21 and the gate terminal GQ1 of the switch Q1, but is not limited to this configuration. The resistor R3 may be a plurality of gate resistors connected to each other. In other words, the resistor R3 is composed of one or more resistors connected to each other.

[0077] Similarly, the resistor R4 is connected in series between the gate terminal GQ11 of the feed-through prevention switch Q11 and the gate terminal GQ2 of the switch Q2, but is not limited to this configuration. The resistor R4 may be composed of multiple resistors connected in mutual positions. In other words, the resistor R4 is composed of one or more resistors connected to each other.

[0078] When resistor R3 is made up of a plurality of resistors connected in series with each other and resistor R4 is made up of a plurality of resistors connected in series with each other, the plurality of resistors constituting resistor R3 may differ in number and resistance value from the plurality of resistors constituting resistor R4.

[0079] The substrate potential stabilization circuit 5 according to the second embodiment is configured to add a combination of a diode D1 and a resistor R3 and a combination of a diode D2 and a resistor R4 to the substrate potential stabilization circuit 1 according to the first embodiment, but is not limited to this configuration. Of these combinations, only the combination of a diode D1 and a resistor R3 may be added, without adding the combination of a diode D2 and a resistor R4. Also, of these combinations, only the combination of a diode D2 and a resistor R4 may be added, without adding the combination of a diode D1 and a resistor R3.

[0080] (Embodiment 3) 7A is a circuit diagram of a bidirectional switch system 100c according to the third embodiment. In this embodiment, the bidirectional switch system 100c according to the first embodiment differs from the bidirectional switch system 100 according to the first embodiment in that the bidirectional switch system 100c according to the first embodiment has diodes D1 and D2, which are rectifying elements of the bidirectional switch system 100b according to the second embodiment, and a controlled voltage stabilizing circuit F1 and a controlled voltage stabilizing circuit F2 added to the gate terminal GQ1 of the switch Q1 and the gate terminal GQ2 of the switch Q2 in the circuit configuration of the bidirectional switch system 100 according to the first embodiment. The controlled voltage stabilizing circuit F1 stabilizes the voltage of the gate terminal GQ1 of the switch Q1. The controlled voltage stabilizing circuit F2 stabilizes the voltage of the gate terminal GQ2 of the switch Q2. This improves the noise resistance of the substrate potential stabilizing circuit 6.

[0081] Next, the circuit configuration of the bidirectional switch system 100c will be described. As shown in Fig. 7A, the bidirectional switch system 100c of this embodiment includes a bidirectional switch element Q0 and a substrate potential stabilization circuit 6. The substrate potential stabilization circuit 6 includes a resistor R1, a resistor R2, a shoot-through current prevention circuit 3, diodes D1 and D2, a control voltage stabilization circuit F1, and a control voltage stabilization circuit F2.

[0082] The control voltage stabilization circuit F1 includes a switch Q12, a resistor R5, and a Zener diode ZD1. The switch Q12 is connected in series between the resistor R1 and the gate terminal GQ1 of the switch Q1 and the resistor R1. Specifically, the switch Q12 has a drain terminal DQ12, a source terminal SQ12, and a gate terminal GQ12 that is a control terminal. The drain terminal DQ12 is electrically connected to the main electrode S2, which is an ohmic electrode that does not have a rectifying function, via a resistor R1. The drain terminal DQ12 of the switch Q12 is connected to the resistor R1. The source terminal SQ12 of the switch Q12 is connected to the gate terminal GQ1 of the switch Q1. The cathode of the Zener diode ZD1 is connected to the gate terminal GQ12 of the switch Q12. The anode of the Zener diode ZD1 is connected to the back electrode S3. Resistor R5 is connected in series between gate terminal GQ12 and main electrode S2 of switch Q12.

[0083] The control voltage stabilization circuit F2 includes a switch Q22, a resistor R6, and a Zener diode ZD2. The switch Q22 is connected in series between the resistor R2 and the gate terminal GQ2 of the switch Q2 to the resistor R2 and the gate terminal GQ2 of the switch Q2. Specifically, the switch Q22 has a drain terminal DQ22, a source terminal SQ22, and a gate terminal GQ22 that is a control terminal. The drain terminal DQ22 is electrically connected to the main electrode S1, which is an ohmic electrode that does not have a rectifying function, via a resistor R2. The drain terminal DQ22 of the switch Q22 is connected to the resistor R2. The source terminal SQ22 of the switch Q22 is connected to the gate terminal GQ2 of the switch Q2. The cathode of the Zener diode ZD2 is connected to the gate terminal GQ22 of the switch Q22. The anode of the Zener diode ZD2 is connected to the back electrode S3. The resistor R6 is connected to the gate of the switch Q22. Terminal GQ22 The gate of switch Q22 is connected in series between Terminal GQ22 and the main electrode S1.

[0084] Next, the circuit operation of the bidirectional switch system 100c will be described. First, the controlled voltage stabilizing circuit F1 and the controlled voltage stabilizing circuit F2, which are different from those in the first embodiment, will be described. When the bidirectional switch element Q0 is in the off state or turned off and a voltage is applied from the main electrode S2 (terminal T2) to the controlled voltage stabilizing circuit F1, a current flows through the Zener diode ZD1 via the resistor R5, and a reference voltage V ZD1 The potential difference between the gate terminal GQ12 and the source terminal SQ12 of the switch Q12 is V GS decreases as the output voltage at the source terminal SQ12 of the switch Q12 increases, eventually reaching V th Therefore, the output voltage at the source terminal SQ12 of the switch Q12 is V ZD1 -V th This output voltage is applied to the gate terminal GQ1 of the switch Q1. This improves the noise immunity of the gate terminal GQ1 of the switch Q1.

[0085] The same is true for the control voltage stabilization circuit F2. When the bidirectional switch element Q0 is turned off and a voltage is applied from the main electrode S1 (terminal T1) to the control voltage stabilization circuit F2, a current flows through the Zener diode ZD2 via the resistor R6, and the reference voltage V ZD2 The potential difference between the gate terminal GQ22 and the source terminal SQ22 of the switch Q22 is V GS decreases as the output voltage at the source terminal SQ22 of the switch Q22 increases, and finally reaches V th Therefore, the output voltage at the source terminal SQ22 of the switch Q22 is V ZD2 -V th This output voltage is applied to the gate terminal GQ2 of the switch Q2. This improves the noise immunity of the gate terminal GQ2 of the switch Q2.

[0086] The overall operation of the substrate potential stabilization circuit 6 is similar to that of the first embodiment, and therefore a description thereof will be omitted.

[0087] As described above, the substrate potential stabilization circuit 6 can prevent the switches Q1 and Q2 from being turned on at the same time. It can also improve the noise resistance of the gates of the switches Q1 and Q2. The control voltage stabilization circuits F1 and F2 protect the switches Q1 and Q2, respectively.

[0088] (Modification of the third embodiment) Below, modifications of the substrate potential stabilization circuit 6 according to the embodiment 3 will be listed. The modifications explained below can be applied in appropriate combination with each of the above embodiments.

[0089] In the third embodiment, the substrate potential stabilization circuit 6 includes the shoot-through current prevention circuit 3, the control voltage stabilization circuit F1, and the control voltage stabilization circuit F2, but is not limited to this configuration. The control voltage stabilization circuit F1 and the control voltage stabilization circuit F2 can be applied separately. In other words, it is possible to apply at least one of the control voltage stabilization circuit F1 and the control voltage stabilization circuit F2, rather than using the shoot-through current prevention circuit 3, the control voltage stabilization circuit F1, and the control voltage stabilization circuit F2 in combination.

[0090] Fig. 7B is a circuit diagram of another bidirectional switch system 100c1 according to the third embodiment. In Fig. 7B, the same parts as those in the bidirectional switch system 100c shown in Fig. 7A are given the same reference numerals. In the bidirectional switch system 100c shown in Fig. 7A, a connection point A connected to the drain terminal DQ11 of the feed-through prevention switch Q11, the anode of the diode D1, and the gate terminal GQ1 of the switch Q1 is directly connected only by wiring to a connection point B where the gate terminal GQ21 of the feed-through prevention switch Q21 is connected to the source terminal SQ12 of the switch Q12. In the bidirectional switch system 100c1 shown in Fig. 7B, the connection point A is connected to the connection point B via a resistor R3. The resistor R3 is connected to the connection points A and B in series between the connection points A and B. This provides a synergistic effect with the second embodiment.

[0091] In the bidirectional switch system 100c shown in Fig. 7A, a connection point C connected to the drain terminal DQ21 of the switch Q21, the anode of the diode D2, and the gate terminal GQ2 of the switch Q2 is directly connected to a connection point D connected to the gate terminal GQ11 of the feed-through prevention switch Q11 and the source terminal SQ22 of the switch Q22, only by wiring. In the bidirectional switch system 100c1 shown in Fig. 7B, the connection point C is connected to the connection point D via the resistor R4 in the second embodiment. The resistor R4 is connected to the connection points C and D in series between the connection points C and D. This provides a synergistic effect with the second embodiment.

[0092] (Embodiment 4) Fig. 8 is a circuit diagram of a bidirectional switch system 100d according to the fourth embodiment. The bidirectional switch system 100d includes a bidirectional switch element Q0 and a substrate potential stabilization circuit 7. The substrate potential stabilization circuit 7 includes a resistor R1, a resistor R2, diodes D1 and D2, a controlled voltage stabilization circuit F3, a controlled voltage stabilization circuit F4, and a shoot-through current prevention circuit 3. In Fig. 8, the same components as those in the bidirectional switch system 100c according to the third embodiment shown in Fig. 7A are denoted by the same reference numerals. The controlled voltage stabilization circuit shown in Fig. 8 F3 The control voltage stabilization circuit F1 according to the third embodiment has a diode D3 and a switch Q13 made of a GIT semiconductor element, which is a gallium nitride semiconductor element, instead of the Zener diode ZD1 of the control voltage stabilization circuit F1 according to the third embodiment, and further has resistors R7 and R8. F4 has a diode D4 instead of the Zener diode ZD2 of the control voltage stabilization circuit F2 shown in FIG. 7A and a switch Q23 made of GIT, which is a gallium nitride based semiconductor element, and further has resistors R9 and R10.

[0093] The circuit configuration of the substrate potential stabilization circuit 7 will be described with reference to Fig. 8. The gate terminal GQ21 of the feedthrough prevention switch Q21 is directly connected to the gate terminal GQ1 of the switch Q1. The gate terminal GQ11 of the feedthrough prevention switch Q11 is directly connected to the gate terminal GQ2 of the switch Q2.

[0094] The control voltage stabilization circuit F3 has a switch Q13, a diode D3, a resistor R7, and a resistor R8 instead of the Zener diode ZD1 in FIG. 7A. Specifically, the switch Q13 has a drain terminal DQ13, a gate terminal GQ13 which is a control terminal, and a source terminal SQ13 which is connected to the back electrode S3 via the diode D3. The drain terminal DQ13 is electrically connected to the main electrode S2 which is an ohmic electrode having no rectification function via a resistor R5. The resistor R5 is connected to the drain terminal DQ13 and the main electrode S2 in series between the drain terminal DQ13 and the main electrode S2. The drain terminal DQ13 of the switch Q13 is connected to the gate terminal GQ12 of the switch Q12. The source terminal SQ13 of the switch Q13 is connected to the anode of the diode D3. The cathode of the diode D3 is connected to the back electrode S3. The resistor R7 is connected to the resistor R8. The resistor R7 is connected to the gate terminal GQ1 of the switch Q1. Resistor R8 is connected to rear electrode S3.

[0095] The resistor R7 is connected to the gate terminal GQ1 of the switch Q1 at a connection point E. The resistor R7 is connected to the resistor R8 at a connection point F. The resistor R8 is connected to the back electrode S3 at a connection point H. The connection point F is connected to the gate terminal GQ1 of the switch Q13. Thus, the resistor R7 is connected to the gate terminal GQ1 of the switch Q1 and the connection point F in series between the gate terminal GQ1 of the switch Q1 and the connection point F. The resistor R8 is connected to the connection point F and the back electrode S3 in series between the connection point F and the back electrode S3. The cathode of the diode D3 is connected to the back electrode S3. The switch Q13 is connected to the anode of the diode D3 and the resistor R5 in series between the anode of the diode D3 and the resistor R5. The switch Q13 has a gate terminal GQ13 that controls the on / off of the switch Q13. The gate terminal GQ13 of the switch Q13 is connected to the connection point F. Resistor R5 is connected in series between gate terminal GQ12 and main electrode S2 of switch Q12.

[0096] The control voltage stabilization circuit F4 has a switch Q23, a diode D4, a resistor R9, and a resistor R10 instead of the Zener diode ZD2 in FIG. 7A. Specifically, the switch Q23 has a drain terminal DQ23, a gate terminal GQ23 which is a control terminal, and a source terminal SQ23 which is connected to the back electrode S3 via the diode D4. The drain terminal DQ23 is connected to the main electrode S1 which is an ohmic electrode having no rectification function. The drain terminal DQ23 of the switch Q23 is connected to the gate terminal GQ22 of the switch Q22. The source terminal SQ23 of the switch Q23 is connected to the anode of the diode D4. The cathode of the diode D4 is connected to the back electrode S3. The resistor R9 is connected to the resistor R10. The resistor R9 is connected to the gate terminal GQ2 of the switch Q2. The resistor R10 is connected to the back electrode S3. The resistor R9 is connected to the gate terminal GQ2 of the switch Q2 at a connection point J. The resistor R9 is connected to the resistor R10 at a connection point K. The resistor R10 is connected to the back electrode S3 at a connection point L. The connection point K is connected to the gate terminal GQ23 of the switch Q23. Thus, the resistor R9 is connected to the gate terminal GQ2 of the switch Q2 and the connection point K in series between the gate terminal GQ2 of the switch Q2 and the connection point K. The resistor R10 is connected to the connection point K and the back electrode S3 in series between the connection point K and the back electrode S3. The cathode of the diode D4 is connected to the back electrode S3. The switch Q23 is connected to the anode of the diode D4 and the resistor R6 in series between the anode of the diode D4 and the resistor R6. The switch Q23 has a gate terminal GQ23 that controls the on / off of the switch Q23. The gate terminal GQ23 of the switch Q23 is connected to the connection point K. Resistor R6 is connected in series between gate terminal GQ22 and main electrode S1 of switch Q22.

[0097] Other circuit configurations of the substrate potential stabilization circuit 7 are similar to those of the substrate potential stabilization circuit 6 shown in FIG. 7A, and therefore description thereof will be omitted.

[0098] Next, the circuit operation of the substrate potential stabilization circuit 7 will be described. First, the operation of the control voltage stabilization circuit F3 is as follows: f3 and the threshold voltage V of the switch Q13. th5 and the potential difference between connection points E and H is V EH and the potential difference between connection points F and H is V FH and the resistance R between connection points E and H EH and the resistance R between connection points F and H FH This will be explained below.

[0099] In the control voltage stabilization circuit F3, V FH >V f3 +V th5 When V EH =V FH ×R EH / R FH Therefore, V EH >(V f3 +V th5 )×R EH / R FH The switch Q1 is turned off at (V f3 +V th5 )×R EH / R FH Set the resistor R so that the value is about 3V. EH , R FH By setting, the control voltage stabilization circuit F3 can EH =3V.

[0100] Next, for the control voltage stabilization circuit F4, the forward voltage V f4 and the threshold voltage V of the switch Q13. th6 and the potential difference between the connection points J and L is V JL and the potential difference between the connection points K and L is V KL and the resistance R between the connection points J and L JL and the resistance R between the connection points K and L KL This will be explained below.

[0101] V KL >V f4 +V th6 When VJL =V KL ×R JL / R KL Therefore, V KL >(V f4 +V th6 )×R JL / R KL The switch Q2 is turned off at (V f4 +V th6 )×R JL / R KL Set the resistor R so that the value is about 3V. JL , R KL By setting, the control voltage stabilization circuit F4 can JL =3V.

[0102] Other circuit operations are similar to those of the substrate potential stabilization circuit 6 according to the third embodiment, and therefore will not be described.

[0103] 9A and 9B show the results of a circuit simulation of the substrate potential stabilization circuit 7 according to this embodiment. FIG. 9A shows the voltage and current when a pulse voltage P41 is applied as pseudo noise to the gate terminal GQ1 of the switch Q1, and FIG. 9B shows an enlarged view of a region Z6 in FIG. 9A. In FIG. 9A and FIG. 9B, a line W13 indicates the gate voltage of the switch Q1. V GQ1 and line W14 indicates the gate voltage of switch Q2. V GQ2 and line W15 indicates the current I Q1 As shown in FIG. 9B, even when the pulse voltage P41 is applied, there is no change in the gate voltage VGQ2. Also, as for the gate voltage VGQ1, there is only an instantaneous voltage fluctuation, and the switch Q1 is not in the on state. Keep it off Therefore, the current flowing through the switch Q1 I Q1 Therefore, the substrate potential stabilization circuit 7 prevents the flow of the shoot-through current and reduces the risk that the switches Q1 and Q2 are turned on at the same time.

[0104] (Modification of the fourth embodiment) The following are examples of modified examples. The modified examples described below can be applied in appropriate combination with the above-described embodiments.

[0105] FIG. 10 is a circuit diagram of another bidirectional switch system 100d1 according to the fourth embodiment. In FIG. 10, the same reference numerals are used for the same parts as in the bidirectional switch system 100d shown in FIG. 8. In the bidirectional switch system 100d shown in FIG. 8, the connection point A where the anode of the diode D1 is connected to the gate terminal GQ1 of the switch Q1 is directly connected only by wiring to the connection point B where the feed-through prevention switch Q11 is connected to the gate terminal GQ1 of the switch Q1. In the bidirectional switch system 100d1 shown in FIG. 10, the connection point A is connected to the connection point B via a resistor R3. The resistor R3 is connected to the connection points A and B in series between the connection points A and B. This makes it possible to further reduce the risk that the switch Q1 and the switch Q2 are simultaneously turned on due to the synergistic effect with the resistor R1, as described in the second embodiment.

[0106] Similarly, in the bidirectional switch system 100d shown in FIG. Q2 10, the connection point C is connected to the connection point D via a resistor R4. The resistor R4 is connected in series to the connection points C and D between the connection points C and D. This makes it possible to further reduce the risk that the switches Q1 and Q2 are turned on simultaneously due to the synergistic effect with the resistor R2, as described in the second embodiment.

[0107] The control voltage stabilization circuits F3 and F4 can be applied independently of the shoot-through current prevention circuit 3. At least one of the control voltage stabilization circuits F3 and F4 may be applied without applying the shoot-through current prevention circuit 3.

[0108] 11 is a circuit diagram of a bidirectional switch system 100e according to the fourth embodiment. The bidirectional switch system 100e includes a bidirectional switch element Q0 and a substrate potential stabilization circuit 8. 。 The gate terminal GQ11 of the anti-shoot-through switch Q11 is connected to the resistor R9, resistor R10, and the gate terminal GQ23 of the switch Q23, not to the gate terminal GQ2 of the switch Q2. K In other words, the gate terminal GQ23 of the switch Q23 is connected to at least the resistors R9 and R10 among the resistors R9, R10, and the gate terminal GQ11. Also, the gate terminal GQ21 of the feedthrough prevention switch Q21 is connected to the resistors R7, R8, and the gate terminal GQ13 of the switch Q13 at a connection point, not to the gate terminal GQ1 of the switch Q1. F In other words, the gate terminal GQ13 of the switch Q13 is connected to at least the resistors R7 and R8 among the resistors R7, R8, and the gate terminal GQ21. In the bidirectional switch system 100e shown in FIG. 11, the gate terminal GQ23 is connected to the resistors R9, R10, and the gate terminal GQ11 at a connection point K The gate terminal GQ13 is connected to the resistor R7, the resistor R8, and the gate terminal GQ21 at a connection point F With this configuration, like the bidirectional switch system 100d, it is possible to stabilize the voltage applied to the gate terminal GQ11 of the feed-through prevention switch Q11 and the voltage applied to the gate terminal GQ21 of the feed-through prevention switch Q21. Stabilization of the gate voltage of at least one of the feed-through prevention switch Q11 and the feed-through prevention switch Q21 may be applied.

[0109] (Embodiment 5) Fig. 12 is a circuit diagram of a bidirectional switch system 100f according to the fifth embodiment. In Fig. 12, the same components as those in the bidirectional switch system 100 according to the first embodiment shown in Fig. 1A are denoted by the same reference numerals. The bidirectional switch system 100f according to the fifth embodiment differs from the bidirectional switch system 100 according to the first embodiment in that it includes voltage-dividing resistors R111 and R112 for protecting the switch Q1 and voltage-dividing resistors R211 and R212 for protecting the switch Q2. The bidirectional switch system 100f according to the fifth embodiment includes a bidirectional switch element Q0 and a substrate potential stabilization circuit 9. The substrate potential stabilization circuit 9 includes a resistor R1, a resistor R2, a switch Q1, a switch Q2, a shoot-through current prevention circuit 3, and voltage-dividing resistors R111, R112, R211, and R212.

[0110] The voltage-dividing resistor R111 is connected in series between the gate terminal GQ2 of the switch Q2 and the gate terminal GQ11 of the feed-through prevention switch Q11. The voltage-dividing resistor R112 is connected in series between the gate terminal GQ1 of the switch Q1 and the gate terminal GQ11 of the feed-through prevention switch Q11. The voltage-dividing resistor R112 is connected in series between the gate terminal GQ1 of the switch Q1 and the gate terminal GQ11 of the feed-through prevention switch Q11. The voltage-dividing resistor R111 is connected to the voltage-dividing resistor R112 at a connection point M. The connection point M is connected to the gate terminal GQ11 of the feed-through prevention switch Q11.

[0111] The voltage-dividing resistor R211 is connected in series between the gate terminal GQ1 of the switch Q1 and the gate terminal GQ21 of the feed-through prevention switch Q21. The voltage-dividing resistor R212 is connected in series between the gate terminal GQ2 of the switch Q2 and the gate terminal GQ21 of the feed-through prevention switch Q21. The voltage-dividing resistor R212 is connected in series between the gate terminal GQ2 of the switch Q2 and the gate terminal GQ21 of the feed-through prevention switch Q21. The voltage-dividing resistor R211 is connected to the voltage-dividing resistor R212 at a connection point N. The connection point N is connected to the gate terminal GQ21 of the feed-through prevention switch Q21. The other circuit configurations are the same as those of the first embodiment, so a description thereof will be omitted.

[0112] Next, the operation of the bidirectional switch system 100f will be described. When the bidirectional switch element Q0 is in the OFF state or turned off, a proper voltage is applied to the switch Q2, and a proper voltage is applied to the prevention switch Q11, the operation is the same as in embodiment 1. At this time, for example, the threshold voltage of the prevention switch Q11 and the prevention switch Q21 is set to 5V, and the voltage dividing resistors R111 and R112 are set so that a divided voltage of 7V is applied to the voltage dividing resistor R111 and a divided voltage of 3V is applied to the voltage dividing resistor R112. R112 When the resistance values ​​of the voltage-dividing resistors R211 and R212 are set so that a divided voltage of 3 V is applied to the voltage-dividing resistor R211 and a divided voltage of 7 V is applied to the voltage-dividing resistor R212, the feed-through prevention switch Q21 is turned off.

[0113] When the gate voltage of switch Q2 becomes excessive, that is, when an excessively large voltage is applied to the gate terminal GQ2 of switch Q2, the voltage applied to the voltage-dividing resistor R211 exceeds the threshold voltage of the shoot-through prevention switch Q21, turning on the shoot-through prevention switch Q21. For example, when the voltage applied to the voltage-dividing resistor R211 is 6V, this exceeds the threshold voltage of the shoot-through prevention switch Q21, which is 5V, and the shoot-through prevention switch Q21 turns on. As a result, damage to the gate terminal GQ2 of switch Q2 can be suppressed.

[0114] The same is true for the gate terminal GQ1 of the switch Q1. When the bidirectional switch element Q0 is in the off state or turned off, a proper voltage is applied to the switch Q1, and a proper voltage is applied to the feed-through prevention switch Q21, the situation is the same as in embodiment 1. When a large voltage is applied to the gate terminal GQ1 of the switch Q1, if the divided voltage of the voltage-dividing resistor R111 exceeds the threshold voltage of the feed-through prevention switch Q11, the feed-through prevention switch Q11 is turned on, and damage to the gate terminal GQ1 of the switch Q1 can be suppressed.

[0115] As described above, by introducing the voltage dividing resistors R111, R112, R211, and R212, it is possible to prevent the switches Q1 and Q2 from being damaged by high voltage noise.

[0116] (summary) As described above, the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) according to the first aspect is electrically connected to the semiconductor element (Q0) having the main electrode (S1), the main electrode (S2), and the back electrode (S3). The substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) includes a switch (Q1), a switch (Q2), and a shoot-through current prevention circuit (3). The switch (Q1) is connected to the main electrode (S1) and the back electrode (S3) between the main electrode (S1) and the back electrode (S3). The switch (Q2) is connected to the main electrode (S2) and the back electrode (S3) between the main electrode (S2) and the back electrode (S3). The shoot-through current prevention circuit (3) prevents the switch (Q1) and the switch (Q2) from being turned on at the same time.

[0117] According to this configuration, it is possible to prevent a shoot-through current from flowing through the substrate potential stabilization circuits (1, 5, 6, 7, 8, 9) of the bidirectional switch system (100).

[0118] The substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) according to the second aspect includes a switch (Q1), a switch (Q2), and a shoot-through current prevention circuit (3) in the first aspect. The switch (Q1) has a gate terminal (GQ1). The switch (Q2) has a gate terminal (GQ2). The shoot-through current prevention circuit (3) includes a resistor (R1), a resistor (R2), a shoot-through prevention switch (Q11), and a shoot-through prevention switch (Q21). The resistor (R1) is connected between the gate terminal (GQ1) and the main electrode (S2) and between the gate terminal (GQ1) and the main electrode (S2). The resistor (R2) is connected between the gate terminal (GQ2) and the main electrode (S1) and between the gate terminal (GQ2) and the main electrode (S1). The penetration prevention switch (Q11) is connected to the gate terminal (GQ1) and the back electrode (S3) between the gate terminal (GQ1) and the back electrode (S3) and has a gate terminal (GQ11). The penetration prevention switch (Q21) is connected to the gate terminal (GQ2) and the back electrode (S3) between the gate terminal (GQ2) and the back electrode (S3) and has a gate terminal (GQ21). The gate terminal (GQ1) is connected to the gate terminal (GQ21), and the gate terminal (GQ2) is connected to the gate terminal (GQ11).

[0119] According to this configuration, when the switch (Q1) is in the on state, the gate terminal and source terminal of the switch (Q2) are short-circuited by the anti-shoot-through switch (Q21), thereby preventing the switch (Q1) and the switch (Q2) from being simultaneously turned on. Also, when the switch (Q2) is in the on state, the gate terminal and source terminal of the switch (Q1) are short-circuited by the anti-shoot-through switch (Q11), thereby preventing the switch (Q1) and the switch (Q2) from being simultaneously turned on. From the above, it is possible to prevent a shoot-through current from flowing through the substrate potential stabilization circuits (1, 5, 6, 7, 8) of the bidirectional switch systems (100, 100b, 100c, 100d, 100e).

[0120] In the second embodiment, the substrate potential stabilization circuit (1, 5, 6, 7) according to the third embodiment further includes a resistor (R3), a resistor (R4), a rectifying element (D1), and a rectifying element (D2). The resistor (R3) is connected to the gate terminal (GQ1) and the gate terminal (GQ21) between the gate terminal (GQ1) and the gate terminal (GQ21). The resistor (R4) is connected to the gate terminal (GQ2) and the gate terminal (GQ11) between the gate terminal (GQ2) and the gate terminal (GQ11). The rectifying element (D1) is connected to the gate terminal (GQ1) and the main electrode (S2) between the gate terminal (GQ1) and the main electrode (S2), and the direction from the gate terminal (GQ1) to the main electrode (S2) is the forward direction. The rectifier element (D2) is connected between the gate terminal (GQ2) and the main electrode (S1), and the direction from the gate terminal (GQ2) to the main electrode (S1) is the forward direction.

[0121] According to this configuration, when the switch (Q1) is turned off, the switch (Q1) is turned off at high speed via the rectifier element (D1), whereas the anti-shoot-through switch (Q21) is turned off via the resistor (R3), and therefore the discharge of the charge of the gate terminal (GQ21) is delayed compared to the switch (Q1). The order of turning off is the switch (Q1) first, followed by the anti-shoot-through switch (Q21). This makes it possible to prevent the switch (Q1) and the switch (Q2) from being in the on state at the same time. Similarly, when the switch (Q2) is turned off, the switch (Q2) is turned off at high speed via the rectifier element (D2), whereas the anti-shoot-through switch (Q11) is turned off via the resistor (R4), and therefore the discharge of the charge of the gate terminal (GQ11) is delayed compared to the switch (Q2). The order of turning off is the switch (Q2) first, followed by the anti-shoot-through switch (Q11). Therefore, it is possible to prevent the switch (Q1) and the switch (Q2) from being turned on at the same time. When the switch (Q1) is turned on, the switch (Q1) is turned on via the resistors (R1) and (R3). In contrast, the through-hole prevention switch (Q21) is turned on only via the resistor (R1). Therefore, the gate terminal (GQ21) of the through-hole prevention switch (Q21) is charged faster than the gate terminal (GQ1) of the switch (Q1). The order of turning on is the through-hole prevention switch (Q21) first, followed by the switch (Q1). Therefore, it is possible to prevent the switch (Q1) and the switch (Q2) from being turned on at the same time. The same is true when the switch (Q2) is turned on. The switch (Q2) is turned on via the resistors (R2) and (R4). In contrast, the through-hole prevention switch (Q11) is turned on only via the resistor (R2). As a result, the gate terminal (GQ11) of the shoot-through prevention switch (Q11) is charged faster than the gate terminal (GQ2) of the switch (Q2). The shoot-through prevention switch (Q11) is turned on first, followed by the switch (Q2). This makes it possible to prevent the switches (Q1) and (Q2) from being turned on at the same time.

[0122] The substrate potential stabilization circuit (6) of the fourth aspect is the same as that of the second or third aspect, and further includes a control voltage stabilization circuit (F1) and a control voltage stabilization circuit (F2). The control voltage stabilization circuit (F1) has a switch (Q12), a resistor (R5), and a Zener diode (ZD1). The control voltage stabilization circuit (F2) has a switch (Q22), a resistor (R6), and a Zener diode (ZD2). In the control voltage stabilization circuit (F1), the resistor (R1) is connected to a gate terminal (GQ1) of the switch (Q1) via the switch (Q12), and the gate terminal (GQ12) of the switch (Q12) is connected to the cathode of the Zener diode (ZD1). Furthermore, in the control voltage stabilization circuit (F1), the back electrode (S3) is connected to the anode of the Zener diode (ZD1), and the gate terminal (GQ12) of the switch (Q12) is connected to the main electrode (S2) via a resistor (R5). In the control voltage stabilization circuit (F2), the resistor (R2) is connected to the gate terminal (GQ2) of the switch (Q2) via a switch (Q22), and the gate terminal (GQ22) of the switch (Q22) is connected to the cathode of the Zener diode (ZD2). Furthermore, in the control voltage stabilization circuit (F2), the back electrode (S3) is connected to the anode of the Zener diode (ZD2), and the gate terminal (GQ22) of the switch (Q22) is connected to the main electrode (S1) via a resistor (R6).

[0123] According to this configuration, the control voltage stabilization circuit (F1) stabilizes the voltage between the resistor (R1) and the switch (Q1). Also, the control voltage stabilization circuit (F2) stabilizes the voltage between the resistor (R2) and the switch (Q2). By stabilizing each voltage, the switch (Q1) and the switch (Q2) can improve their resistance to high voltage noise.

[0124] In the substrate potential stabilization circuit (7, 8) of the fifth aspect, SecondOr in the third aspect, the semiconductor device further includes a control voltage stabilizing circuit (F3) and a control voltage stabilizing circuit (F4). The control voltage stabilizing circuit (F3) has a switch (Q12), a switch (Q13), a resistor (R7), a resistor (R8), and a rectifying element (D3). The control voltage stabilizing circuit (F4) has a switch (Q22), a switch (Q23), a resistor (R9), a resistor (R10), and a rectifying element (D4). In the control voltage stabilizing circuit (F3), the resistor (R7) and the resistor (R8) are connected in series between the gate terminal (GQ1) of the switch (Q1) and the back electrode (S3). The back electrode (S3) is connected to the cathode of the rectifying element (D3). Furthermore, in the control voltage stabilization circuit (F3), a switch (Q13) is connected between the anode of the rectifier element (D3) and the resistor (R5). The gate terminal of the switch (Q13) is connected to the resistor (R7) and the resistor (R8), and the resistor (R5) is connected between the gate of the switch (Q12) and the main electrode (S2) and between the gate of the switch (Q12) and the main electrode (S2). In the control voltage stabilization circuit (F4), a resistor (R9) and a resistor (R10) are connected in series with each other between the gate terminal (GQ2) of the switch (Q2) and the back electrode (S3). The back electrode (S3) is connected to the cathode of the rectifier element (D4). Furthermore, in the control voltage stabilization circuit (F4), a switch (Q23) is connected between the anode of the rectifier element (D4) and the resistor (R6). The gate of the switch (Q23) is connected to a resistor (R9) and a resistor (R10). A resistor (R6) is connected between the gate of the switch (Q22) and the main electrode (S1) and between the gate of the switch (Q22) and the main electrode (S1).

[0125] According to this configuration, the control voltage stabilization circuit (F1) stabilizes the voltage between the resistor (R1) and the switch (Q1). Also, the control voltage stabilization circuit (F2) stabilizes the voltage between the resistor (R2) and the switch (Q2). By stabilizing each voltage, the switch (Q1) and the switch (Q2) can improve their resistance to high voltage noise. Also, this circuit configuration can be realized by a monolithic circuit.

[0126] In the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of the sixth aspect, in any one of the first to fifth aspects, the semiconductor element is a dual-gate bidirectional switch element (Q0).

[0127] This configuration makes it possible to configure a bidirectional switch element (Q0) that is excellent in voltage resistance and stability of electrical characteristics.

[0128] In the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of the seventh aspect, in the fifth aspect, the switch (Q1), the switch (Q2), the switch (Q12), the switch (Q22), the switch (Q13), the switch (Q23), the feed-through prevention switch (Q11), and the feed-through prevention switch (Q21) are transistors, and terminals connected to each ohmic electrode, which is a contact without rectification, are drain terminals, terminals connected to each back surface electrode (S3) are source terminals, and each control terminal is a gate terminal.

[0129] This configuration allows for highly accurate control by the transistor, and also allows for a monolithic circuit to be configured together with the bidirectional switch element (Q0).

[0130] In the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of the eighth aspect, in the seventh aspect, the switch (Q1), the switch (Q2), the switch (Q12), the switch (Q22), the switch (Q13), the switch (Q23), the feed-through prevention switch (Q11), and the feed-through prevention switch (Q21) are gallium nitride-based semiconductor elements.

[0131] According to this configuration, gallium nitride-based semiconductor element materials are semiconductor elements that can withstand higher voltages, have higher heat resistance, be smaller, and operate faster than conventional silicon, and similar effects can be expected when used in circuits.

[0132] In the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of the ninth aspect, in the eighth aspect, a semiconductor element (Q0) having a main electrode (S1), a main electrode (S2) and a back electrode (S3), a switch (Q1), a switch (Q2), a switch (Q12), a switch (Q22), a switch (Q13), a switch (Q23), a feed-through prevention switch (Q11), and a feed-through prevention switch (Q21) are formed as a monolithic circuit on the same chip.

[0133] This configuration has the advantage that it is easy to reduce the size and increase the degree of integration.

[0134] In the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of the tenth aspect, in any one of the first to ninth aspects, the semiconductor element (Q0) is a gallium nitride-based semiconductor element.

[0135] According to this embodiment, gallium nitride-based semiconductor element materials are semiconductor elements that can withstand higher voltages, have higher heat resistance, be smaller in size, and have higher speeds than conventional silicon, and similar effects can be expected when used in circuits.

[0136] A bidirectional switch system (100, 100b, 100c, 100d, 100e, 100f) of an eleventh aspect includes a substrate potential stabilization circuit (1, 5, 6, 7, 8, 9) of any one of the first to tenth aspects, and a semiconductor element (Q0).

[0137] According to this configuration, the bidirectional switch system (100, 100b, 100c, 100d, 100e, 100f) suppresses the shoot-through current flowing through the substrate potential stabilization circuit (1, 5, 6, 7, 8, 9), and is a system that is resistant to noise. [Explanation of symbols]

[0138] 1,5,6,7,8,9 Substrate potential stabilization circuit 2 Main Bidirectional Switch 3 Through current prevention circuit F Connection point (first connection point) K connection point (second connection point) Q0 Semiconductor element Q1 switch (first switch) Q11 Penetration prevention switch (first penetration prevention switch) Q2 switch (second switch) Q21 Penetration prevention switch (second penetration prevention switch) Q12 Switch (3rd switch) Q22 Switch (4th switch) Q13 Switch (5th switch) Q23 Switch (6th switch) R1 resistor (1st resistor) R2 resistor (second resistor) R3 resistor (third resistor) R4 resistor (4th resistor) R5 resistor (5th resistor) R6 resistor (6th resistor) R7 resistor (7th resistor) R8 resistor (8th resistor) R9 resistor (9th resistor) R10 resistor (10th resistor) D1 Rectifier element (first rectifier element) D2 Rectifier element (second rectifier element) D3 Rectifier (third rectifier) D4 rectifier element (fourth rectifier element) ZD1 Zener diode (first Zener diode) ZD2 Zener diode (second Zener diode) 100, 100b, 100c, 100d, 100e, 100f Two-way switch system GQ1 Gate terminal (first control terminal) GQ2 Gate terminal (second control terminal) GQ11 Gate terminal (third control terminal) GQ21 Gate terminal (4th control terminal) F1 Control voltage stabilization circuit (first control voltage stabilization circuit) F2 Control voltage stabilization circuit (second control voltage stabilization circuit) F3 Control voltage stabilization circuit (first control voltage stabilization circuit) F4 Control voltage stabilization circuit (second control voltage stabilization circuit)

Claims

1. A substrate potential stabilization circuit configured to be connected to a bidirectional switch element including a semiconductor substrate, a first main electrode connected to the semiconductor substrate, a second main electrode connected to the semiconductor substrate, and a back surface electrode connected to the semiconductor substrate, a first switch connected in series between the first main electrode and the back surface electrode; a second switch connected in series between the second main electrode and the back surface electrode; a shoot-through current prevention circuit that prevents the first switch and the second switch from being turned on simultaneously; Equipped with the first switch has a first control terminal that controls on / off of the first switch; the second switch has a second control terminal that controls on / off of the second switch, The shoot-through current prevention circuit includes: a first resistor connected in series to the second main electrode between the first control terminal and the second main electrode of the first switch; a second resistor connected in series to the first main electrode between the second control terminal of the second switch and the first main electrode; a first penetration prevention switch connected in series between the first control terminal and the back electrode of the first switch; a second penetration prevention switch connected in series between the second control terminal and the back electrode of the second switch; having The first penetration prevention switch has a third control terminal that controls on / off of the first penetration prevention switch, the second penetration prevention switch has a fourth control terminal that controls on / off of the second penetration prevention switch, The first control terminal of the first switch is electrically connected to the fourth control terminal of the second penetration prevention switch, the second control terminal of the second switch is electrically connected to the third control terminal of the first feed-through prevention switch.

2. The shoot-through current prevention circuit comprises: a third resistor connected in series between the first control terminal and the fourth control terminal; a fourth resistor connected in series between the second control terminal and the third control terminal; a first rectifying element connected in series between the first control terminal and the second main electrode, the first rectifying element having a forward direction from the first control terminal to the second main electrode; a second rectifying element connected in series between the second control terminal and the first main electrode, the second rectifying element having a forward direction from the second control terminal to the first main electrode; 2. The substrate potential stabilization circuit according to claim 1, further comprising:

3. A first controlled voltage stabilization circuit having a third switch, a fifth resistor, and a first Zener diode; a second controlled voltage stabilization circuit having a fourth switch, a sixth resistor and a second Zener diode; Further comprising: the first resistor is connected to the first control terminal of the first switch via the third switch; the third switch has a control terminal that controls on / off of the third switch, the control terminal of the third switch is connected to the cathode of the first Zener diode, and the anode of the first Zener diode is connected to the back electrode; the control terminal of the third switch is connected to the second main electrode via the fifth resistor, and the second resistor is connected to the second control terminal of the second switch via the fourth switch; the fourth switch has a control terminal that controls on / off of the fourth switch, the control terminal of the fourth switch is connected to the cathode of the second Zener diode, and the anode of the second Zener diode is connected to the back electrode; 3. The substrate potential stabilization circuit according to claim 1, wherein the control terminal of the fourth switch is connected to the first main electrode via the sixth resistor.

4. A first controlled voltage stabilization circuit having a third switch, a fifth switch, a fifth resistor, a seventh resistor, an eighth resistor, and a third rectifier element; a second controlled voltage stabilization circuit including a fourth switch, a sixth switch, a sixth resistor, a ninth resistor, a tenth resistor, and a fourth rectifier element; Further equipped with the seventh resistor is connected in series between the first control terminal and the first connection point of the first switch, and between the first control terminal and the first connection point of the first switch; the eighth resistor is connected in series between the first connection point and the back surface electrode, The cathode of the third rectifying element is connected to the back electrode, the fifth switch is connected in series between the anode of the third rectifier element and the fifth resistor, and between the anode of the third rectifier element and the fifth resistor; the fifth switch has a control terminal that controls on / off of the fifth switch, the control terminal of the fifth switch is connected to the first connection point; the third switch has a control terminal that controls on / off of the third switch, the fifth resistor is connected in series between the control terminal and the second main electrode of the third switch, and between the control terminal and the second main electrode of the third switch; the ninth resistor is connected in series between the second control terminal and the second connection point of the second switch, and between the second control terminal and the second connection point of the second switch; the tenth resistor is connected in series between the second connection point and the back surface electrode, The cathode of the fourth rectifying element is connected to the back electrode, the sixth switch is connected in series between the anode of the fourth rectifier element and the sixth resistor, and to the anode of the fourth rectifier element and the sixth resistor; the sixth switch has a control terminal that controls on / off of the sixth switch, The control terminal of the sixth switch is connected to the second connection point, the fourth switch has a control terminal that controls on / off of the fourth switch, 3. The substrate potential stabilization circuit according to claim 1, wherein the sixth resistor is connected in series between the control terminal and the first main electrode of the fourth switch.

5. A substrate potential stabilization circuit as described in claim 4, wherein the fourth control terminal of the second anti-piercing switch is connected to the first control terminal, and the third control terminal of the first anti-piercing switch is connected to the second control terminal.

6. The fourth control terminal of the second anti-penetration switch is connected to the first connection point, 5. The substrate potential stabilization circuit according to claim 4, wherein the third control terminal of the first feed-through prevention switch is connected to the second connection point.

7. A substrate potential stabilization circuit as described in claim 4, wherein the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first anti-passthrough switch, and the second anti-passthrough switch are transistors having a drain terminal electrically connected to an ohmic electrode not having a rectifying function, a source terminal electrically connected to the back electrode, and a gate terminal.

8. A substrate potential stabilization circuit as described in claim 7, wherein the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first anti-piercing switch, and the second anti-piercing switch are gallium nitride based semiconductor elements.

9. A substrate potential stabilization circuit as described in claim 8, wherein the bidirectional switch element, the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the first anti-through switch, and the second anti-through switch are formed as a monolithic circuit on the same chip.

10. The substrate potential stabilization circuit according to claim 1, wherein the bidirectional switch element is a dual-gate type bidirectional switch element.

11. The substrate potential stabilization circuit according to claim 1, wherein the bidirectional switch element is a gallium nitride-based semiconductor element.

12. A substrate potential stabilization circuit according to any one of claims 1 to 11, The bidirectional switch element; Two-way switch system with

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