Gallium nitride half-bridge drive circuit

Abstract

The invention belongs to the technical field of gallium nitride driving, and relates to a gallium nitride half-bridge type driving circuit. The gallium nitride driving circuit comprises a high-frequency driving signal generation module used for generating a first high-frequency signal and a second high-frequency signal which are complementary and free of dead zones; the input end of the isolation type dead zone generation module is connected with the output end of the high-frequency driving signal generation module, and the isolation type dead zone generation module is used for adjusting the dead zone time of the first high-frequency signal and the second high-frequency signal to a preset value and outputting a first target high-frequency signal and a second target high-frequency signal; the input end of the voltage matching module is connected with the output end of the isolation type dead zone generation module, and the voltage matching module is used for adjusting the voltage of the first target high-frequency signal and the second target high-frequency signal; the input end of the isolation driving module is connected with the output end of the voltage matching module, and the isolation driving module is used for adjusting the rising edges and the falling edges of the first target high-frequency signal and the second target high-frequency signal and outputting a first driving signal and a second driving signal to drive an upper tube and a lower tube in the gallium nitride half-bridge circuit.

Description

Technical Field

[0001] The present invention relates to the field of gallium nitride driving technology, and in particular to a gallium nitride half-bridge driving circuit. Background Art

[0002] In recent years, data center power supplies, wireless power transmission, RF power amplification and other application fields have put forward increasingly stringent requirements on the volume, weight and efficiency of power electronic equipment, which in turn leads to the continuous increase in the switching frequency requirements of power electronic power devices in these power supply devices. For silicon-based semiconductor power devices, there is limited room for further improvement in the upper limit of the switching frequency. At the same time, with the increasing improvement of the manufacturing process of gallium nitride power devices, a large number of gallium nitride power devices have gradually been applied to the field of ultra-high frequency power electronics. Since gallium nitride devices have low on-state and switching losses and better reverse recovery characteristics than field effect transistors (Si-MOSFET), they can significantly improve the overall efficiency of power supplies. In addition, gallium nitride materials themselves have the advantages of high bandgap width, high electron mobility, high critical breakdown electric field and high electron saturation rate. Therefore, switching power amplifiers based on gallium nitride power devices can provide high-frequency, high-power and low-loss sinusoidal AC power to RF loads. In order to give full play to the advantages of gallium nitride power devices, it is necessary to design a stable and high-frequency drive circuit.

[0003] The GaN half-bridge circuit is a circuit architecture widely used in high-efficiency power conversion. Its core feature is the use of GaN power devices (such as GaN-HEMT) as switching elements to achieve efficient and high-speed power conversion. Figure 1 FIG. 1 is a schematic diagram of a gallium nitride half-bridge circuit and a gallium nitride half-bridge bootstrap driving circuit in the prior art, wherein the gallium nitride half-bridge circuit includes two gallium nitride power devices (such as Figure 1 In and ), upper tube As a high-side switch connected to the positive pole of the power supply, the lower tube As a low-side switch connected to the load or ground, by controlling the upper tube and down tube The GaN half-bridge bootstrap drive circuit includes a bootstrap capacitor , Bootstrap Diode and bootstrap driver IC , when the bootstrap driver chip Controlling the lower tube in the GaN half-bridge circuit based on PWM signal When turned on, a closed path is formed between the positive pole of the power supply and the ground, and the load current flows through the lower tube , so that the upper tube The source is close to ground potential, and the supply voltage is passed through the bootstrap diode Storing charge in the bootstrap capacitor ; When the bootstrap driver chip Control the lower tube based on PWM signal Close, upper pipe When turned on, the bootstrap capacitor Discharge for upper tube The gate of the upper tube is provided with a floating voltage so that the difference between the gate potential and the source potential is greater than the threshold voltage, thereby ensuring that the upper tube Effective conduction; due to the upper tube and down tube Simultaneous conduction will cause the circuit to short-circuit, so it is often on the upper tube and down tube A certain time interval (i.e. dead time) is reserved during the switching process. and down tube Close at the same time, thus preventing the upper tube and down tube However, during the dead time after the upper tube is turned off, the current continues to flow in the original direction due to the inductance in the load, and the lower tube As a freewheeling channel, it works in the third quadrant, that is, the direction of voltage and current is opposite to that of normal conduction. Drain-source voltage is a negative voltage, which will further cause the bootstrap capacitor is overcharged, and then the upper tube Too high a voltage is applied to the gate of the upper tube, causing The overvoltage will break down, thus damaging the GaN power device. In order to avoid the overcharge, the bootstrap drive circuit can only drive the GaN half-bridge circuit at a lower operating frequency. However, reducing the operating frequency of the bootstrap drive circuit also reduces the switching rate of the GaN half-bridge circuit, making it impossible to fully utilize the advantage of the fast switching speed of the GaN power device, thereby reducing the response speed and power density of the GaN half-bridge circuit.

[0004] In summary, when the GaN half-bridge bootstrap driving circuit in the prior art drives the GaN half-bridge circuit, there is a problem that the bootstrap capacitor is overcharged, which leads to overvoltage breakdown of the upper tube; if the operating frequency of the bootstrap driving circuit is reduced to reduce the chance of overcharging the bootstrap capacitor, the advantage of the fast switching speed of the GaN power device cannot be fully utilized, thereby reducing the response speed and power density of the GaN half-bridge circuit. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art of the gallium nitride half-bridge bootstrap driving circuit that the bootstrap capacitor is overcharged, thereby causing the upper tube to be broken down by overvoltage.

[0006] In order to solve the above technical problems, the present invention provides a gallium nitride half-bridge driving circuit, comprising: A high-frequency driving signal generating module, used for generating a first high-frequency signal and a second high-frequency signal which are complementary and have no dead zone; the duty ratios of the first high-frequency signal and the second high-frequency signal are both 50%; An isolated dead zone generating module, whose first input terminal is connected to the first output terminal of the high-frequency driving signal generating module, and whose second input terminal is connected to the second output terminal of the high-frequency driving signal generating module; used to adjust the dead zone time of the first high-frequency signal and the second high-frequency signal to a preset value, and output a first target high-frequency signal and a second target high-frequency signal; A voltage matching module, comprising a first voltage matching circuit and a second voltage matching circuit; an input end of the first voltage matching circuit is connected to a first output end of the isolated dead zone generating module, and is used to adjust the voltage of the first target high-frequency signal; an input end of the second voltage matching circuit is connected to a second output end of the isolated dead zone generating module, and is used to adjust the voltage of the second target high-frequency signal; An isolation driving module comprises a first isolation driving circuit and a second isolation driving circuit; an input end of the first isolation driving circuit is connected to an output end of the first voltage matching circuit, and is used to adjust the rising edge and the falling edge of the first target high-frequency signal, and output a first driving signal to drive an upper tube in a gallium nitride half-bridge circuit; an input end of the second isolation driving circuit is connected to an output end of the second voltage matching circuit, and is used to adjust the rising edge and the falling edge of the second target high-frequency signal, and output a second driving signal to drive a lower tube in the gallium nitride half-bridge circuit.

[0007] Preferably, it also includes an isolated power supply module, and the isolated power supply module includes: A first isolated power supply chip, whose output end is connected to the first output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; A second isolated power supply chip, whose output end is connected to the second output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; a third isolation power supply chip, whose output end is connected to the power input end of the first isolation drive circuit, and is used to supply power to the first isolation drive circuit; A fourth isolation power supply chip, whose output end is connected to the power input end of the second isolation drive circuit, is used to supply power to the second isolation drive circuit.

[0008] Preferably, a protection module is also included, and the protection module includes: a first protection circuit, whose input end is connected to the output end of the first isolation drive circuit, and whose output end is connected to the gate of the upper tube in the gallium nitride half-bridge circuit, and is used to suppress the oscillation of the first drive signal; The second protection circuit has an input end connected to the output end of the second isolation drive circuit and an output end connected to the gate of the lower tube in the gallium nitride half-bridge circuit, and is used to suppress the oscillation of the second drive signal.

[0009] Preferably, the isolated dead zone generating module comprises: An isolation drive chip, wherein the first signal input pin thereof is used as the first input end of the isolation dead zone generating module, and is connected to the first output end of the high-frequency drive signal generating module; the second signal input pin thereof is used as the second input end of the isolation dead zone generating module, and is connected to the second output end of the high-frequency drive signal generating module; the first signal output pin thereof is used as the first output end of the isolation dead zone generating module; and the second signal output pin thereof is used as the second output end of the isolation dead zone generating module; A first resistor, a first end of which is connected to the dead time input pin of the isolation driver chip, and a second end of which is grounded, and the dead time of the first high-frequency signal and the second high-frequency signal is adjusted by changing the resistance value of the first resistor; wherein the calculation formula of the dead time is: , in, Indicates the dead time of the first target high frequency signal and the second target high frequency signal; Represents the resistance value of the first resistor.

[0010] Preferably, the first voltage matching circuit and the second voltage matching circuit both include: a second resistor, a first end of which serves as an input end of the voltage matching circuit; A third resistor has a first end connected to the second end of the second resistor as an output end of the voltage matching circuit, and a second end grounded.

[0011] Preferably, the first isolation driving circuit and the second isolation driving circuit both include: A high-speed driver chip, whose signal input pin serves as the input end of the isolation driver circuit; whose power input pin serves as the power input end of the isolation driver circuit; and whose enable pin is grounded; a fourth resistor, a first end of which is connected to an output high-end signal pin of the high-speed driver chip; A fifth resistor, a first end of which is connected to the output low-end signal pin of the high-speed driving chip, and a second end of which is connected to the second end of the fourth resistor as the output end of the isolation driving circuit.

[0012] Preferably, the first protection circuit and the second protection circuit both include: A diode, whose anode is grounded and whose cathode serves as the input terminal of the protection circuit; a transient voltage suppression diode, the anode of which is connected to the cathode of the diode and the cathode of which is grounded; A sixth resistor has a first end connected to the anode of the transient voltage suppression zener diode as the output end of the protection circuit, and a second end connected to the ground.

[0013] Preferably, models of the first isolation power supply chip, the second isolation power supply chip, the third isolation power supply chip and the fourth isolation power supply chip include B0509-2WR3 and B0505-2WR3.

[0014] Preferably, the models of the isolation driver chip include Nsi6602A and Ucc21520.

[0015] Preferably, the models of the high-speed driver chip include HD1001 and LMG1020.

[0016] The gallium nitride half-bridge driving circuit provided by the present application adopts a two-stage driving method to generate two driving signals to isolate and drive the upper tube and the lower tube in the gallium nitride half-bridge circuit. First, two complementary high-frequency signals with no dead zone and a duty cycle of 50% are generated; the dead zone time of the two high-frequency signals is adjusted by using an isolated dead zone generating module to realize primary driving, so as to prevent the two start signals from overlapping at a high level so that the upper tube and the lower tube in the gallium nitride bridge circuit are turned on at the same time, resulting in a short circuit; in order to match the voltage of the two high-frequency signals with the input voltage of the isolated driving module, two isolated voltage matching circuits are designed to respectively adjust the voltage of the two high-frequency signals, thereby increasing the operating voltage range of the isolated dead zone generating module and the isolated driving module, and thereby increasing the operating frequency of the driving circuit; finally, two independent isolated driving circuits are used to perform secondary driving. Driving, since each isolated driving circuit is a single-input single-output circuit, the edges of the two high-frequency signals can be adjusted respectively, and two complementary driving signals with dead time are generated to independently drive the upper tube and the lower tube in the gallium nitride bridge circuit; the present application does not use bootstrap capacitors and bootstrap diodes to bootstrap drive the upper tube and the lower tube in the gallium nitride half-bridge circuit, but directly generates two complementary driving signals with dead time to isolate and drive the upper tube and the lower tube, and by providing a more stable and independent gate voltage for the upper tube and the lower tube, the problem of overcharging of the bootstrap capacitor and thus causing damage to the device is avoided, and there is no need to reduce the operating frequency of the driving circuit and the rate of the switching action in the gallium nitride half-bridge circuit, thereby realizing high-frequency driving of the gallium nitride half-bridge circuit, and giving full play to the advantage of the fast switching speed of the gallium nitride power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein Figure 1 A schematic diagram of a gallium nitride half-bridge circuit provided in the present application and a gallium nitride half-bridge bootstrap drive circuit in the prior art; Figure 2 A schematic diagram of the overall structure of the gallium nitride half-bridge drive circuit provided in this application; Figure 3 A schematic diagram of a complementary first high-frequency signal and a second high-frequency signal without dead zone provided by the present application; Figure 4 This is a schematic diagram of the input signal and output signal of the isolated dead zone generation module provided in the present application; wherein, Figure 4 (a) is a schematic diagram of the input signal of the isolated dead zone generation module. Figure 4 (b) is a schematic diagram of the output signal of the isolated dead zone generation module; Figure 5 A schematic diagram of the circuit principle of an isolated dead zone generation module provided in this application; Figure 6 A schematic diagram of a voltage matching circuit principle provided in this application; Figure 7 A schematic diagram of the principle of an isolation drive circuit provided in this application; Figure 8 A schematic diagram of the circuit principle of an isolated power supply chip provided in this application; Fig. 9 A schematic diagram of a protection circuit principle provided for this application; Fig.10 A schematic diagram of the principle of a gallium nitride half-bridge drive circuit provided in an embodiment of the present application; Fig.11 The driving signal waveform diagram of the gallium nitride half-bridge circuit driven by the driving circuit provided in the embodiment of the present application; wherein: Fig.11 (a) is the first driving signal waveform. Fig.11 (b) in the figure is the waveform diagram of the second driving signal. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0019] See also Figure 2 , Figure 2 The overall structural schematic diagram of the gallium nitride half-bridge drive circuit provided in the present application includes: a high-frequency drive signal generating module, an isolated dead zone generating module, a voltage matching module and an isolated drive module.

[0020] The high-frequency driving signal generating module is used to generate a first high-frequency signal and a second high-frequency signal that are complementary and have no dead zone, wherein the duty cycle of the first high-frequency signal and the second high-frequency signal are both 50%.

[0021] For example, Figure 3 The figure shows a schematic diagram of a complementary first high-frequency signal and a second high-frequency signal without dead zone provided in an embodiment of the present application, in which A and B represent the first high-frequency signal and the second high-frequency signal respectively.

[0022] The first input end of the isolated dead zone generating module is connected to the first output end of the high-frequency driving signal generating module, and the second input end is connected to the second output end of the high-frequency driving signal generating module; it is used to adjust the dead zone time of the first high-frequency signal and the second high-frequency signal to a preset value, and output the first target high-frequency signal and the second target high-frequency signal.

[0023] Specifically, the complementary first high-frequency signal without dead zone and the second high-frequency signal will generate a complementary first target high-frequency signal and a second target high-frequency signal with dead zone time and a duty cycle slightly less than 50% after passing through the isolated dead zone generating module. By controlling the dead zone time of the two signals, it is possible to prevent the high-level overlap of the two driving signals, thereby causing the upper tube and the lower tube in the gallium nitride half-bridge circuit to be turned on at the same time, resulting in a short circuit, causing device damage and other consequences.

[0024] For example, Figure 4 Shown is a schematic diagram of input signals and output signals of the isolated dead zone generating module provided in an embodiment of the present application. Figure 4 (a) is a schematic diagram of input signals of the isolated dead zone generating module, in which A and B respectively represent the first high-frequency signal and the second high-frequency signal output by the high-frequency driving signal generating module; Figure 4 (b) is a schematic diagram of the output signal of the isolated dead zone generating module, in which A and B respectively represent the first target high-frequency signal and the second target high-frequency signal output by the isolated dead zone generating module, and DT is the dead zone time of the two high-frequency signals.

[0025] The voltage matching module includes a first voltage matching circuit and a second voltage matching circuit.

[0026] The input end of the first voltage matching circuit is connected to the first output end of the isolated dead zone generating module, and is used to adjust the voltage of the first target high-frequency signal. The input end of the second voltage matching circuit is connected to the second output end of the isolated dead zone generating module, and is used to adjust the voltage of the second target high-frequency signal.

[0027] The output voltage of the isolated dead zone generating module is adjusted by using a voltage matching module to match the input voltage of the isolated driving module, so that both the isolated dead zone generating module and the isolated driving module can operate within a wider voltage range.

[0028] The isolation driving module includes a first isolation driving circuit and a second isolation driving circuit.

[0029] The input end of the first isolation driving circuit is connected to the output end of the first voltage matching circuit, and is used to adjust the rising edge and falling edge of the first target high-frequency signal, and output the first driving signal to drive the upper tube in the gallium nitride half-bridge circuit. The input end of the second isolation driving circuit is connected to the output end of the second voltage matching circuit, and is used to adjust the rising edge and falling edge of the second target high-frequency signal, and output the second driving signal to drive the lower tube in the gallium nitride half-bridge circuit.

[0030] The present application does not use a bootstrap capacitor and a bootstrap diode to bootstrap drive the upper tube and the lower tube in the gallium nitride half-bridge circuit, but directly generates two complementary driving signals with dead zones to drive the upper tube and the lower tube in isolation. By providing a more stable and independent gate voltage for the upper tube and the lower tube, the problem of overcharging of the bootstrap capacitor and thus causing damage to the device is avoided. There is no need to reduce the operating frequency of the driving circuit and the rate of the switching action in the gallium nitride half-bridge circuit, so that high-frequency driving of the gallium nitride half-bridge circuit can be achieved, and the advantage of the fast switching speed of the gallium nitride power device can be fully utilized.

[0031] Specifically, the isolated dead zone generation module includes: An isolation drive chip, wherein the first signal input pin thereof is used as the first input end of the isolation dead zone generating module, and is connected to the first output end of the high-frequency drive signal generating module; the second signal input pin thereof is used as the second input end of the isolation dead zone generating module, and is connected to the second output end of the high-frequency drive signal generating module; the first signal output pin thereof is used as the first output end of the isolation dead zone generating module; and the second signal output pin thereof is used as the second output end of the isolation dead zone generating module; The first resistor has a first end connected to the dead time input pin of the isolation driver chip and a second end grounded. The dead time of the first high frequency signal and the second high frequency signal is adjusted by changing the resistance value of the first resistor.

[0032] Furthermore, the isolation driver chip may be a chip with hardware-configured dead time, such as Nsi6602A, Ucc21520, etc.

[0033] For example, Figure 5 The figure shows a circuit schematic diagram of an isolated dead zone generation module provided by this embodiment, which uses the Nsi6602A chip as the isolated driver chip. In the figure, VIA and VIB are the first input terminal and the second input terminal of the isolated dead zone generation module; VDDI is the input power supply terminal of the isolated dead zone generation module; GNDI is the input ground pin; NC is the empty signal pin; VDDA and VDDB are the first output power supply terminal and the second output power supply terminal of the isolated dead zone generation module; GNDA and GNDB are the output ground pins; DT is the dead zone time input pin of the isolated driver chip, connected to the first resistor R 1 , by changing the first resistor R 1 The size of can control the size of the dead time. Specifically, the calculation formula of the dead time is: , in, Indicates the dead time of the first target high frequency signal and the second target high frequency signal; Represents the resistance value of the first resistor.

[0034] Furthermore, the first voltage matching circuit and the second voltage matching circuit both include: a second resistor, a first end of which serves as an input end of the voltage matching circuit; A third resistor has a first end connected to the second end of the second resistor as an output end of the voltage matching circuit, and a second end grounded.

[0035] like Figure 6 The voltage matching circuit provided in this embodiment is shown as a schematic diagram of the principle of the voltage matching circuit. The circuit is composed of a second resistor in series. and the third resistor composition, It is the output signal of the isolated dead zone generation module. is the output signal of the voltage matching circuit; By adjusting the values ​​of the second resistor and the third resistor, the voltage matching between the isolated dead zone generating module and the isolated driving module can be achieved.

[0036] Furthermore, the first isolation driving circuit and the second isolation driving circuit both include: A high-speed driver chip, whose signal input pin serves as the input end of the isolation driver circuit; whose power input pin serves as the power input end of the isolation driver circuit; and whose enable pin is grounded; a fourth resistor, a first end of which is connected to an output high-end signal pin of the high-speed driver chip; A fifth resistor has a first end connected to the output low-end signal pin of the high-speed driving chip, and a second end connected to the second end of the fourth resistor as the output end of the isolation driving circuit.

[0037] Furthermore, high-speed driver chips can be selected from models such as Qianhong Microelectronics' HD1001 chip, T1's LMG1020, etc., and their response speed can reach ns level.

[0038] For example, Figure 7 The diagram shows the principle diagram of the isolation driving circuit when the high-speed driving chip model is HD1001 provided in this embodiment. The left side of the figure shows the circuit principle diagram of the HD1001 chip. The VDD pin of the HD1001 chip serves as the power input terminal of the isolation driving circuit; IN+ is the signal input pin; IN- is the enable pin; U1 is the same-direction Schmitt trigger; U2 is the reverse Schmitt trigger; U3 is the AND gate; Q1 is an N-channel field effect transistor; Q2 is a P-channel field effect transistor; OUTH is the output high-end signal pin; OUTL is the output low-end signal pin; IN- inputs a low-level signal, IN+ inputs a high-level signal, and outputs a high-frequency signal through the AND gate, driving Q1 and Q2 to turn on or off, so that OUTH and OUTL output large-current, ultra-high-speed driving signals, and then pass through the fourth resistor. and the fifth resistor The edge of the driving signal is optimized so as to output the driving signal to drive the GaN half-bridge circuit.

[0039] Alternatively, if Figure 2 As shown, in some embodiments of the present application, the gallium nitride half-bridge driving circuit further includes an isolated power supply module, and the isolated power supply module specifically includes: A first isolated power supply chip, whose output end is connected to the first output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; A second isolated power supply chip, whose output end is connected to the second output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; A third isolation power supply chip, whose output end is connected to the power input end of the first isolation drive circuit, and is used to supply power to the first isolation drive circuit; The fourth isolation power supply chip has an output end connected to the power input end of the second isolation drive circuit and is used to supply power to the second isolation drive circuit.

[0040] Furthermore, the first isolation power supply chip, the second isolation power supply chip, the third isolation power supply chip and the fourth isolation power supply chip can use module power supplies such as Jinshengyang B0509-2WR3 and Yichuan B0505-2WR3.

[0041] For example, Figure 8 The figure shows a circuit principle schematic diagram of an isolated power supply chip provided in this embodiment. By using an isolated power supply with a large isolation distance between the input and the output to respectively power the input and output ends of the isolated dead zone generating module, the first isolation driving circuit and the second isolation driving circuit, the influence of the high voltage part on the low voltage part can be minimized, thereby further ensuring the isolation drive of the upper tube and the lower tube in the gallium nitride half-bridge circuit.

[0042] Furthermore, if Figure 2 As shown, in some embodiments of the present application, the gallium nitride half-bridge driving circuit further includes a protection module, which specifically includes: A first protection circuit, whose input end is connected to the output end of the first isolation driving circuit, and whose output end is connected to the gate of the upper tube in the gallium nitride half-bridge circuit, is used to suppress the oscillation of the first driving signal; The second protection circuit has an input end connected to the output end of the second isolation drive circuit and an output end connected to the gate of the lower tube in the gallium nitride half-bridge circuit, and is used to suppress the oscillation of the second drive signal.

[0043] Since the first drive signal and the second drive signal need to be transmitted to the upper tube and the lower tube in the gallium nitride half-bridge circuit through wires, parasitic parameters in the wires may cause the drive signal waveform to oscillate, thereby causing damage to the gallium nitride device in the gallium nitride half-bridge circuit. Therefore, the present application designs a first protection circuit and a second protection circuit to respectively suppress the waveform oscillation of the first drive signal and the second drive signal, thereby preventing damage to the drive circuit or the device in the gallium nitride half-bridge circuit caused by the drive signal waveform oscillation due to the presence of parasitic parameters.

[0044] Furthermore, the first protection circuit and the second protection circuit both include: A diode, whose anode is grounded and whose cathode serves as the input terminal of the protection circuit; A transient voltage suppression Zener diode, whose anode is connected to the cathode of the diode and whose cathode is grounded; A sixth resistor has a first end connected to the anode of the transient voltage suppression diode as the output end of the protection circuit, and a second end connected to the ground.

[0045] For example, Fig. 9 The schematic diagram of the protection circuit provided by this embodiment is shown in FIG. The cathode of the diode D1 is connected to the signal input terminal of the protection circuit; the anode of the transient suppression voltage stabilizing diode D2 is connected to the cathode of the diode D1; the sixth resistor The first end of the protection circuit is connected to the positive electrode of the transient suppression voltage zener diode D2 as the output end of the protection circuit, and the positive electrode of the diode D1, the negative electrode of the transient suppression voltage zener diode D2 and the sixth resistor are connected to the GaN field effect transistor Q in the GaN half-bridge circuit. The second end is grounded.

[0046] Due to the existence of parasitic inductance on the wire side, high-frequency signals will inevitably produce oscillations during transmission. Excessive oscillations will cause damage to the drive circuit or the devices in the GaN half-bridge circuit. By designing the negative voltage clamp of the reverse parallel diode D1 to be near the diode tube voltage drop, the transient suppression Zener diode D2 is used to absorb the voltage spike. At the same time, the sixth resistor That is, it can perform impedance matching and can also serve as a pull-down resistor to prevent the GaN field effect transistor Q in the GaN half-bridge circuit from being mis-turned on.

[0047] like Fig.10The figure shows a principle schematic diagram of the gallium nitride half-bridge driving circuit provided by the present embodiment, in which 10 is an isolated dead zone generating module; 20 is a voltage matching module, 201 is a first matching circuit, and 202 is a second matching circuit; 30 is an isolated driving module, 301 is a first isolated driving circuit, and 302 is a second isolated driving module; 40 is an isolated power supply module, 401 is a first isolated power supply chip, 402 is a second isolated power supply chip, 403 is a third isolated power supply chip, and 404 is a fourth isolated power supply chip; 50 is a protection module, 501 is a first protection circuit, and 502 is a second protection circuit; QA and QB are the upper tube and the lower tube in the gallium nitride half-bridge circuit respectively.

[0048] Fig.11 Shown using Fig.10 The driving signal waveform diagram obtained by the driving circuit shown in the figure driving the gallium nitride half-bridge circuit; wherein, Fig.11 (a) is the first driving signal waveform, which can achieve 4MHz ultra-high-speed driving; Fig.11 (b) in the figure is the second driving signal waveform, which can achieve ultra-high-speed driving at 8MHz level. Fig.11 It can be seen that the gallium nitride half-bridge drive circuit provided in the present application can achieve MHz-level ultra-high-speed drive in actual work.

[0049] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A gallium nitride half-bridge drive circuit, characterized in that: include: A high-frequency driving signal generating module, used for generating a first high-frequency signal and a second high-frequency signal which are complementary and have no dead zone; The duty cycle of the first high-frequency signal and the second high-frequency signal are both 50%; An isolated dead zone generating module, whose first input terminal is connected to the first output terminal of the high-frequency driving signal generating module, and whose second input terminal is connected to the second output terminal of the high-frequency driving signal generating module; used to adjust the dead zone time of the first high-frequency signal and the second high-frequency signal to a preset value, and output a first target high-frequency signal and a second target high-frequency signal; A voltage matching module, comprising a first voltage matching circuit and a second voltage matching circuit; an input end of the first voltage matching circuit is connected to a first output end of the isolated dead zone generating module, and is used to adjust the voltage of the first target high-frequency signal; an input end of the second voltage matching circuit is connected to a second output end of the isolated dead zone generating module, and is used to adjust the voltage of the second target high-frequency signal; An isolation driving module, comprising a first isolation driving circuit and a second isolation driving circuit; an input end of the first isolation driving circuit is connected to an output end of the first voltage matching circuit, and is used to adjust the rising edge and the falling edge of the first target high-frequency signal, and output a first driving signal to drive the upper tube in the gallium nitride half-bridge circuit; The input end of the second isolation driving circuit is connected to the output end of the second voltage matching circuit, and is used to adjust the rising edge and the falling edge of the second target high-frequency signal, and output a second driving signal to drive the lower tube in the gallium nitride half-bridge circuit.

2. The gallium nitride half-bridge driving circuit according to claim 1, characterized in that: It also includes an isolated power supply module, the isolated power supply module includes: A first isolated power supply chip, whose output end is connected to the first output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; A second isolated power supply chip, whose output end is connected to the second output power supply end of the isolated dead zone generating module, and is used to supply power to the output end of the isolated dead zone generating module; a third isolation power supply chip, whose output end is connected to the power input end of the first isolation drive circuit, and is used to supply power to the first isolation drive circuit; A fourth isolation power supply chip, whose output end is connected to the power input end of the second isolation drive circuit, is used to supply power to the second isolation drive circuit.

3. The gallium nitride half-bridge driving circuit according to claim 1, characterized in that: Also included is a protection module, the protection module comprising: a first protection circuit, whose input end is connected to the output end of the first isolation drive circuit, and whose output end is connected to the gate of the upper tube in the gallium nitride half-bridge circuit, and is used to suppress the oscillation of the first drive signal; The second protection circuit has an input end connected to the output end of the second isolation drive circuit and an output end connected to the gate of the lower tube in the gallium nitride half-bridge circuit, and is used to suppress the oscillation of the second drive signal.

4. The gallium nitride half-bridge driving circuit according to claim 1, characterized in that: The isolated dead zone generating module comprises: An isolation drive chip, wherein the first signal input pin thereof is used as the first input end of the isolation dead zone generating module, and is connected to the first output end of the high-frequency drive signal generating module; the second signal input pin thereof is used as the second input end of the isolation dead zone generating module, and is connected to the second output end of the high-frequency drive signal generating module; the first signal output pin thereof is used as the first output end of the isolation dead zone generating module; and the second signal output pin thereof is used as the second output end of the isolation dead zone generating module; A first resistor, a first end of which is connected to the dead time input pin of the isolation driver chip, and a second end of which is grounded, and the dead time of the first high-frequency signal and the second high-frequency signal is adjusted by changing the resistance value of the first resistor; wherein the calculation formula of the dead time is: ， in, Indicates the dead time of the first target high frequency signal and the second target high frequency signal; Represents the resistance value of the first resistor.

5. The gallium nitride half-bridge driving circuit according to claim 1, characterized in that: The first voltage matching circuit and the second voltage matching circuit both include: a second resistor, a first end of which serves as an input end of the voltage matching circuit; A third resistor has a first end connected to the second end of the second resistor as an output end of the voltage matching circuit, and a second end grounded.

6. The gallium nitride half-bridge driving circuit according to claim 1, characterized in that: The first isolation driving circuit and the second isolation driving circuit both include: A high-speed driver chip, whose signal input pin serves as the input end of the isolation driver circuit; whose power input pin serves as the power input end of the isolation driver circuit; and whose enable pin is grounded; a fourth resistor, a first end of which is connected to an output high-end signal pin of the high-speed driver chip; A fifth resistor, a first end of which is connected to the output low-end signal pin of the high-speed driving chip, and a second end of which is connected to the second end of the fourth resistor as the output end of the isolation driving circuit.

7. The gallium nitride half-bridge driving circuit according to claim 3, characterized in that: The first protection circuit and the second protection circuit both include: A diode, whose anode is grounded and whose cathode serves as the input terminal of the protection circuit; a transient voltage suppression diode, the anode of which is connected to the cathode of the diode and the cathode of which is grounded; A sixth resistor has a first end connected to the anode of the transient voltage suppression zener diode as the output end of the protection circuit, and a second end connected to the ground.

8. The gallium nitride half-bridge driving circuit according to claim 2, characterized in that: Models of the first isolation power supply chip, the second isolation power supply chip, the third isolation power supply chip and the fourth isolation power supply chip include B0509-2WR3 and B0505-2WR3.

9. The gallium nitride half-bridge driving circuit according to claim 4, characterized in that: The models of the isolation driver chip include Nsi6602A and Ucc21520.

10. The gallium nitride half-bridge driving circuit according to claim 6, characterized in that: The models of the high-speed driver chips include HD1001 and LMG1020.

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