GaN power device bridge arm forward crosstalk suppression circuit

Abstract

A bridge arm forward crosstalk suppression circuit of a GaN power device is connected between a grid electrode and a source electrode of the GaN power device in a main circuit, and comprises a push-pull circuit, a negative voltage generation circuit and a recovery circuit. The negative voltage generation circuit is used for generating required negative voltage and preventing the device from being mistakenly conducted due to forward crosstalk; the recovery circuit is used for releasing generated negative voltage before negative crosstalk comes so as to prevent reverse breakdown of a device grid electrode. A passive element is used for generating negative voltage, positive crosstalk can be effectively restrained, meanwhile, negative crosstalk cannot be increased, and reverse breakdown of a device grid electrode is prevented. The method has the advantages of simple design, high reliability, low cost and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of driving power electronic devices, and specifically provides a GaN power device bridge arm forward crosstalk suppression circuit. Background Art

[0002] In recent years, power electronic converters have developed towards high frequency, high power density and high efficiency, and traditional Si-based switching devices can no longer meet existing needs. The third-generation semiconductor devices made of GaN materials have the advantages of low on-resistance, high thermal conductivity and fast switching speed, making them one of the most promising devices to replace Si-based devices.

[0003] As the switching frequency increases, the influence of parasitic parameters on the bridge circuit will intensify, making the crosstalk phenomenon more serious. At the same time, the forward threshold voltage and gate reverse safety voltage of GaN power devices are relatively small. The forward voltage spike caused by the crosstalk effect will more easily cause the device to be mis-conducted, increase switching losses, and affect the performance of the switch tube and the reliability of the power electronic converter. Therefore, studying how to suppress the crosstalk voltage generated by such devices in the bridge arm circuit is of great significance to improving the reliability of the power electronic converter during operation.

[0004] At present, the forward crosstalk suppression circuit of the bridge arm of GaN power devices adds a negative voltage source to suppress it. Although it can suppress the forward crosstalk and prevent the device from being mis-conducted, it will increase the design cost and increase the negative crosstalk. The risk of reverse breakdown of the device gate increases. Summary of the invention

[0005] The purpose of the present invention is to improve the existing crosstalk suppression circuit in view of the problems existing in the prior art, and propose a GaN power device bridge arm forward crosstalk suppression circuit, which uses passive components to generate negative voltage, can effectively suppress positive crosstalk, and will not increase negative crosstalk, thereby preventing the device gate from reverse breakdown.

[0006] The technical solution adopted by the present invention is:

[0007] A GaN power device bridge arm forward crosstalk suppression circuit, the crosstalk suppression circuit is connected between the gate and the source of the GaN power device in the main circuit, the crosstalk suppression circuit comprises: a push-pull circuit, a negative voltage generating circuit, and a recovery circuit;

[0008] The push-pull circuit is used to drive a GaN power device.

[0009] The negative voltage generating circuit is used to generate negative voltage to prevent the GaN power device from being mis-conducted due to forward crosstalk;

[0010] The recovery circuit is used to release the negative voltage generated before the negative crosstalk occurs to prevent the gate of the GaN power device from reverse breakdown.

[0011] The push-pull circuit includes: a MOS tube S1 and a MOS tube S2, wherein the drain of the MOS tube S1 is connected to the positive electrode of the power supply V CC The source of the MOS tube S1 is used as the output end of the push-pull circuit, the source of the MOS tube S1 is connected to the source of the MOS tube S2, the drain of the MOS tube S2 is connected to the ground end, and the gate of the MOS tube S1 and the gate of the MOS tube S2 are commonly connected to the PWM signal input end.

[0012] The negative voltage generating circuit includes: voltage zener diodes D1, D4, capacitor C1, resistor R1, and diode D3; wherein the cathode of the voltage zener diode D1 is connected to one end of the capacitor C1, and are jointly connected to the output end of the push-pull circuit; the anode of the voltage zener diode D1 is respectively connected to the other end of the capacitor C1 and one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the cathode of the voltage zener diode D4, and the anode of the voltage zener diode D4 is connected to the ground end.

[0013] The recovery circuit includes: a diode D2 and a resistor R2, wherein the cathode of the diode D2 is connected to the anode of the diode D3 in the negative voltage generating circuit, the anode of the diode D2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the ground.

[0014] The present invention provides a GaN power device bridge arm forward crosstalk suppression circuit, and the technical effects are as follows:

[0015] The circuit of the present invention uses passive components to generate negative voltage, which can effectively suppress positive crosstalk, while not increasing negative crosstalk and preventing reverse breakdown of the device gate. It has the advantages of simple design, high reliability, low cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Block diagram of a half-bridge circuit.

[0017] Figure 2 FIG. 4 is a structural diagram of an embodiment of the present invention in which the suppression circuit is applied to a half-bridge circuit.

[0018] Figure 3 This is the switching timing diagram of the half-bridge circuit of the GaN power device.

[0019] Figure 4(1) shows Figure 1 Circuit schematic diagram of the circuit operating in mode M1;

[0020] Figure 4(2) shows Figure 1 Circuit schematic diagram of the circuit operating in mode M2;

[0021] Figure 4(3) shows Figure 1 Circuit schematic diagram of the circuit operating in mode M3;

[0022] Figure 4 (4) is Figure 1 Circuit schematic diagram of the circuit operating in mode M4;

[0023] Figure 4(5) shows Figure 1 Circuit schematic diagram of the circuit operating in mode M5;

[0024] Figure 4(6) is Figure 1 Schematic diagram of the circuit operating in mode M6.

[0025] Figure 5 This is the forward crosstalk waveform without the traditional crosstalk suppression circuit.

[0026] Figure 6 This is a forward crosstalk waveform diagram of the crosstalk suppression circuit provided by the present invention.

[0027] Figure 7 This is the negative crosstalk waveform without the traditional crosstalk suppression circuit.

[0028] Figure 8 This is a negative crosstalk waveform diagram of the suppression circuit proposed in the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0030] This embodiment provides a GaN power device bridge arm forward crosstalk suppression circuit, which is connected between the gate and source of the GaN power device in the main circuit, and includes: a push-pull circuit, a negative voltage generation circuit, and a recovery circuit. The negative voltage generation circuit is used to generate the required negative voltage to prevent the device from being mis-conducted due to forward crosstalk; the recovery circuit is used to release the generated negative voltage before the negative crosstalk comes, so as to prevent the device gate from reverse breakdown.

[0031] The push-pull circuit includes: MOS tubes S1 and S2; wherein the drain of the MOS tube S1 is connected to the positive electrode of the power supply V CC The source is connected as the output end of the push-pull circuit and is connected to the source of the MOS tube S2. The drain of the MOS tube S2 is connected to the power ground. The gates of the MOS tube S1 and the MOS tube S2 are commonly connected to the PWM signal input end.

[0032] The negative voltage generating circuit includes: voltage-stabilizing diodes D1 and D4, capacitor C1, resistor R1 and diode D3; wherein, the cathode of the voltage-stabilizing diode D1 is connected to one end of the capacitor C1, and is jointly connected to the output end of the push-pull circuit, the anode of the voltage-stabilizing diode D1 is connected to the other end of the capacitor C1, and is jointly connected to one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the cathode of the voltage-stabilizing diode D4, and the anode of the voltage-stabilizing diode D4 is grounded.

[0033] The recovery circuit includes: a diode D2 and a resistor R2; wherein the cathode of the diode D2 is connected to the anode of the diode D3 in the negative voltage generating circuit, the anode of the diode D2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the power ground.

[0034] More specifically, the crosstalk suppression circuit of the present invention is applied to Figure 2 The half-bridge circuit shown above has the upper bridge arm device (upper tube) Q H It is the active tube, the lower bridge arm device (lower tube) Q L For passive tubes, the upper bridge arm device Q H For the lower bridge arm device Q L How to suppress the crosstalk of H With v L Respectively represent the upper tube Q H With down tube Q L The driving signal V CCH With V CCL Respectively represent the upper tube Q H With down tube Q L The driving side power supply; C gdH and C gdL Respectively represent the upper tube Q H With down tube Q L The gate-drain parasitic capacitance of gsH and C gsL Respectively represent the upper tube Q H With down tube Q L The gate-source parasitic capacitance; C dsH and C dsL Respectively represent the upper tube Q H With down tube Q L The drain-source parasitic capacitance; L and C are the filter inductor and capacitor respectively; R is the load resistance; V DC It is the DC bus power supply.

[0035] The following is combined with Figure 3 The timing diagram of the GaN power device half-bridge circuit shown in the figure is used to illustrate the working principle of the crosstalk suppression circuit proposed in the present invention, which is as follows:

[0036] Mode M1 [t0-t1]: Upper tube Q H In the off state, the lower tube Q L The diode D3 is forward-conducted, and the capacitor C1 is charged, forming a positive voltage on the left and a negative voltage on the right. The final voltage value of the capacitor C1 is the voltage value V of the voltage regulator tube D1. D1 , down tube Q L The gate drive voltage is the voltage value V of the Zener diode D4. D4 The sum of the forward voltage drop of diode D3.

[0037] Mode M2 ​​[t1-t2]: Upper tube Q H Keep the off state, the lower tube Q L Shutdown, this stage includes Q L The turn-off time and dead time of the lower tube Q are increased. In this stage, diodes D3 and D1 are turned off in reverse, and diode D2 is turned on in forward direction. The negative voltage of capacitor C1 accelerates the lower tube Q L At the same time, capacitor C1 discharges through resistors R1 and R2.

[0038] Mode M3 [t2-t3]: Down tube Q L Keep off, the upper tube Q H Open, down pipe Q L The drain-source voltage V ds It rises rapidly, generating Miller current, generating positive voltage on the right and negative voltage on the left on the driving resistors R1 and R3, and causing positive crosstalk. At this time, the voltage of capacitor C1 is still positive on the left and negative on the right, offsetting the voltage on R1 and R3 and suppressing positive crosstalk.

[0039] Mode M4 [t3-t4]: Down tube Q L Keep off, the upper tube Q H Keep it open. Capacitor C1, resistors R1 and R2, and diode D2 form a loop, and C1 continues to discharge through R1 and R2.

[0040] Mode M5 [t4-t5]: Down tube Q L Keep off, the upper tube Q H Keep it turned on. At this time, capacitor C1 has been fully discharged.

[0041] Mode M6 [t5-t6]: Down tube Q L Keep off, the upper tube Q H At this time, the lower tube Q L The drain-source voltage V ds It drops rapidly, generating Miller current, generating negative right and positive left voltages on driving resistors R1 and R3, and generating negative crosstalk. Before this mode, capacitor C1 has been discharged, the voltage value is zero, and the negative crosstalk will not increase.

[0042] In order to verify the effectiveness of the forward crosstalk suppression circuit of the GaN power device proposed in the present invention, a double-pulse test platform was built for testing, and a comparative analysis was performed with a traditional circuit without crosstalk suppression.

[0043] The GaN power device used in this experiment is the GS61008P of GaN system, and the experimental conditions are: the bus voltage is 50V and the load current is 30A; the parameters of the crosstalk suppression circuit proposed in the present invention are as follows: the capacitor C1 is 7.5nf, the resistor R1 is 1Ω, the resistor R2 is 200Ω, the resistor R3 is 9Ω, the models of the Zener diodes D1 and D4 are MMSZ5229BT1G and MMSZ5232A respectively, and the model of the diodes D2 and D3 is 1N5818.

[0044] The forward crosstalk comparison results are as follows: Figure 5 and Figure 6 As shown, Figure 5 For the traditional case without crosstalk suppression circuit, the forward crosstalk is 2.63V. Figure 6 is the forward crosstalk of the crosstalk suppression circuit proposed in the present invention, and its value is 0.14V, which is less than the threshold voltage V of GS61008P th =1.7V, reducing the probability of false conduction.

[0045] The negative crosstalk comparison results are as follows: Figure 7 and Figure 8 As shown, Figure 7 For the traditional case without crosstalk suppression circuit, the negative crosstalk is -2.92V. Figure 8 The negative crosstalk of the crosstalk suppression circuit proposed in the present invention has a value of -2.91V, and the difference between the two is not much.

Claims

1. A GaN power device bridge arm forward crosstalk suppression circuit, Features: The crosstalk suppression circuit is connected between the gate and the source of the GaN power device in the main circuit, and the crosstalk suppression circuit includes: a push-pull circuit, a negative voltage generating circuit, and a recovery circuit; The push-pull circuit is used to drive the GaN power device; The negative voltage generating circuit is used to generate negative voltage to prevent the GaN power device from being mis-conducted due to forward crosstalk; The recovery circuit is used to release the negative voltage generated before the negative crosstalk occurs to prevent the gate of the GaN power device from reverse breakdown.

2. According to claim 1, a GaN power device bridge arm forward crosstalk suppression circuit, Features: The push-pull circuit includes: a MOS tube S 1 、MOS tube S 2 , wherein the MOS tube S 1 The drain and the positive power supply V CC Connection, MOS tube S 1 The source of the MOS tube S is used as the output end of the push-pull circuit. 1 The source of the MOS tube S 2 The source of the MOS tube S 2 The drain of MOS tube S is connected to the ground terminal. 1 The gate and MOS tube S 2 The gates of the transistors are commonly connected to the PWM signal input terminal.

3. According to claim 1, a GaN power device bridge arm forward crosstalk suppression circuit, Features: The negative voltage generating circuit comprises: a voltage stabilizing diode D 1 , D 4 , capacitor C 1 , resistor R 1 , diode D 3 ; Among them, the voltage regulator diode D 1 Cathode and capacitor C 1 and connected together to the output end of the push-pull circuit; the voltage regulator diode D 1 The anode is connected to the capacitor C 1 The other end of the resistor R 1 One end of the resistor R 1 The other end of the diode D 3 The anode of the diode D 3 The cathode of the Zener diode D is connected 4 The cathode of the Zener diode D 4 The anode of the resistor is connected to ground.

4. According to claim 1, a GaN power device bridge arm forward crosstalk suppression circuit, Features: The recovery circuit includes: a diode D 2 , resistor R 2 , diode D 2 The cathode of the diode D in the negative voltage generating circuit 3 The anode of the diode D is connected 2 The anode and resistor R 2 One end of the resistor R 2 The other end is connected to the ground.

5. A GaN power device bridge arm forward crosstalk suppression circuit as claimed in any one of claims 1 to 4, Features: Include mode M 1 ~ Mode M 6 : Mode M 1 :Upper tube Q H In the off state, the lower tube Q L Open; diode D 3 Forward conduction, capacitor C 1 Charging, forming a positive voltage on the left and a negative voltage on the right, capacitor C 1 The final voltage value of the voltage regulator tube D 1 The voltage regulation value V D1 , down tube Q L The gate drive voltage of the Zener diode D 4 The voltage regulation value V D4 With diode D 3 The sum of the forward voltage drops; Mode M 2 :Upper tube Q H Keep the off state, the lower tube Q L Shutdown, this stage includes Q L The turn-off time and dead time of the diode D 3 and D 1 Reverse blocking, diode D 2 Forward conduction; capacitor C 1 The negative pressure accelerates the Q L The turn-off speed of capacitor C 1 Through the resistor R 1 With R 2 Discharge; Mode M 3 :Down tube Q L Keep off, the upper tube Q H Open, down pipe Q L The drain-source voltage V ds Rapidly rises, generating Miller current, driving resistor R 1 and R 3 The voltage is positive on the right and negative on the left, and positive crosstalk occurs. At this time, the capacitor C 1 The voltage is still positive on the left and negative on the right, canceling out R 1 and R 3 The voltage on the resistor suppresses the forward crosstalk. Mode M 4 :Down tube Q L Keep off, the upper tube Q H Keep open; capacitor C 1 , resistor R 1 With R 2 、Diode D 2 Form a loop, C 1 By R 1 With R 2 Continuous discharge; Mode M 5 :Down tube Q L Keep off, the upper tube Q H Keep it open; at this time, the capacitor C 1 The discharge has been completed; Mode M 6 :Down tube Q L Keep off, the upper tube Q H Turn off; at this time, the lower tube Q L The drain-source voltage V ds Rapidly decreases, generating Miller current, driving resistor R 1 and R 3 The voltage generated is negative on the right and positive on the left, which produces negative crosstalk. Before this mode, the capacitor C 1 The discharge is complete, the voltage value is zero, and the negative crosstalk will not increase.

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