A driving circuit, a driving device and a driving method

Abstract

The present application discloses a driving circuit, a driving device and a driving method, which relate to the technical field of power system management. The driving circuit comprises: the drain of a first depletion-type gallium nitride device is connected to a high-voltage input power supply, the source of the first depletion-type gallium nitride device is connected to the drain of a field effect transistor, and the gate of the first depletion-type gallium nitride device is connected to the source of the field effect transistor through a first diode; the input end of a detection trigger module is connected to the drain of the field effect transistor, the output end of the detection trigger module is connected to a logic driving module, and the detection trigger module is connected to an isolated power supply; the input end of the logic driving module is connected to a controller, the output end of the logic driving module is connected to the gate of the first depletion-type gallium nitride device, and the logic driving module is connected to a power supply and an isolated power supply. The present application can give full play to the flow capacity of depletion-type gallium nitride devices.

Description

Technical Field

[0001] The present application relates to the technical field of power system management, and in particular to a driving circuit, a driving device and a driving method. Background Art

[0002] In power electronics systems, the drive circuit is located between the main power circuit (i.e., the high-power power transmission and conversion part) and the digital control core (such as a microcontroller, DSP, etc., responsible for generating control signals). Its essence is to amplify the PWM signal (Pulse Width Modulation) generated by the digital control core to drive the opening and closing of power switching devices (such as IGBT, MOSFET, etc.) to achieve precise control of the current and voltage in the main power circuit. Traditional depletion-type GaN is a cascade architecture. The drive circuit indirectly drives the depletion-type GaN to work by driving the power switching device, and cannot directly drive the depletion-type GaN to work, resulting in the limitation of the current capacity of the depletion-type GaN.

[0003] Therefore, in order to fully utilize the current-carrying capacity of depletion-mode GaN, a driving circuit that can directly drive power switching devices is urgently needed. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the related art, the purpose of the present application is to provide a driving circuit, a driving device and a driving method, which can fully exert the current-carrying capacity of a depletion-mode gallium nitride device.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a driving circuit, the driving circuit comprising: a first depletion-mode gallium nitride device, a first diode, a field effect transistor, a detection trigger module, and a logic driving module;

[0007] The drain of the first depletion-mode gallium nitride device is connected to a high-voltage input power supply, the source of the first depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the first depletion-mode gallium nitride device is connected to the source of the field effect transistor through the first diode; the input end of the detection trigger module is connected to the drain of the field effect transistor, the output end of the detection trigger module is connected to the logic drive module, and the detection trigger module is connected to an isolated power supply; the input end of the logic drive module is connected to a controller, the output end of the logic drive module is connected to the gate of the first depletion-mode gallium nitride device, and the logic drive module is connected to a power supply and the isolated power supply; wherein,

[0008] The field effect transistor is used to turn off the first depletion-mode gallium nitride device after the first depletion-mode gallium nitride device is powered on and the drain voltage of the field effect transistor is greater than a first threshold value; the detection trigger module is used to monitor the voltage of the isolated power supply when the first depletion-mode gallium nitride device is in the off state and the detection trigger module is powered on, and send a DRV signal to the logic drive module if the voltage value of the isolated power supply is greater than a second threshold value; the logic drive module is used to connect with the power supply in response to the DRV signal, process the received PWM IN signal sent by the controller to obtain a PWM signal, and use the PWM signal to drive the first depletion-mode gallium nitride device to be in the on state or the off state.

[0009] Optionally, the detection trigger module includes a detection trigger functional unit and a switch tube; the input end of the switch tube is connected to the detection trigger functional unit, the first output end of the switch tube is connected to the source of the first depletion-mode gallium nitride device, and the second output end of the switch tube is connected to the isolated power supply; the switch tube is used to be in an on state when the voltage value of the isolated power supply is greater than the second threshold, so that the detection trigger functional unit sends the DRV signal to the logic drive module.

[0010] Optionally, the logic driving module includes: a first AND gate unit, a second AND gate unit, a first gate driver, and a second gate driver; the first input end of the first AND gate unit is connected to the detection trigger function unit, the second input end of the first AND gate unit is connected to the power supply, the output end of the first AND gate unit is connected to the input end of the first gate driver, the output end of the first gate driver is respectively connected to the gate of the field effect transistor and the first input end of the second AND gate unit, the second input end of the second AND gate unit is connected to the controller, the output end of the second AND gate unit is connected to the input end of the second gate driver, and the output end of the second gate driver is connected to the gate of the first depletion-type gallium nitride device, wherein the first AND gate unit is used to respond to the DRV signal to output a high-level signal, so that the output end of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in a conducting state; the second AND gate unit is used to respond to the PWM EN signal to convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs the PWM signal to directly drive the first depletion-type gallium nitride device to be in a conducting state or an off state.

[0011] Optionally, the driving circuit also includes a first isolated communication module and a second isolated communication module; the first input end of the first AND gate unit is connected to the detection trigger function unit through the first isolated communication module; the output end of the second AND gate unit is connected to the input end of the second gate driver through the second isolated communication module.

[0012] Optionally, the driving circuit further includes a second diode and a second depletion-mode gallium nitride device connected in parallel with the first depletion-mode gallium nitride device; wherein the drain of the second depletion-mode gallium nitride device is connected to the high-voltage input power supply, the source of the second depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the second depletion-mode gallium nitride device is connected to the source of the field effect transistor through the second diode.

[0013] Optionally, both the first depletion-mode gallium nitride device and the second depletion-mode gallium nitride device have a zero voltage when in an on state and a negative voltage when in an off state.

[0014] Optionally, the field effect transistor is an NMOS tube, and the switch tube is an NMOS tube or a PMOS tube.

[0015] In a second aspect, the present application provides a driving device, including: the driving device includes a driving circuit as described in any one of the first aspects above, and the driving device is applied to a power electronic system.

[0016] In a third aspect, the present application provides a driving method, which is applied to the driving circuit described in any one of the first aspects above, and the driving method includes: after the first depletion-mode gallium nitride device is powered on, the field effect transistor and the drain voltage of the field effect transistor are greater than a first threshold, so that the first depletion-mode gallium nitride device is in an off state; after the first depletion-mode gallium nitride device is in an off state and the detection trigger module is powered on, the detection trigger module monitors the voltage of the isolated power supply, and if the voltage value of the isolated power supply is greater than a second threshold, sends a DRV signal to the logic driving module; the logic driving module is connected to the power supply in response to the DRV signal, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to drive the first depletion-mode gallium nitride device to be in an on state or an off state.

[0017] Optionally, the logic driving module is connected to the power supply in response to the DRV signal, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to drive the first depletion-mode gallium nitride device to be in an on state or an off state, including: the first AND gate unit outputs a high-level signal in response to the DRV signal, so that the output end of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in an on state; the second AND gate unit is used to respond to the PWM EN signal, convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs the PWM signal, and directly drives the first depletion-mode gallium nitride device to be in an on state or an off state.

[0018] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0019] The present application provides a driving circuit, a driving device and a driving method, wherein the voltage of an isolated power supply is monitored by a detection trigger module, and if the voltage value of the isolated power supply is greater than a second threshold, a DRV signal is sent to a logic driving module; the logic driving module responds to the DRV signal and is connected to the power supply, and a PWM IN signal received from a controller is processed to obtain a PWM signal, and the PWM signal is used to directly drive a first depletion-type gallium nitride device to be in an on state or an off state; that is, the first depletion-type gallium nitride device is directly driven by the combination of the detection trigger module and the logic driving module, and the functions of zero voltage turn-on and negative voltage turn-off are realized without changing the control logic of the first depletion-type gallium nitride device, thereby giving full play to the strong current-carrying capacity of the first depletion-type gallium nitride device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the structure of a driving circuit in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of a specific structure of a driving circuit provided in one embodiment of the present application;

[0023] Figure 3 A timing logic diagram of a driving circuit provided in one embodiment of the present application;

[0024] Figure 4 A schematic diagram of a specific structure of a driving circuit provided in another embodiment of the present application;

[0025] Figure 5 A schematic diagram of the structure of a driving device provided in one embodiment of the present application;

[0026] Figure 6 A schematic flow chart of a driving method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0029] In power electronic systems, the drive circuit is located between the main power circuit (i.e., the high-power power transmission and conversion part) and the digital control core (such as a microcontroller, DSP, etc., responsible for generating control signals). Its essence is to amplify the PWM signal (Pulse Width Modulation) generated by the digital control core to drive the opening and closing of power switching devices (such as IGBT, MOSFET, etc.) to achieve precise control of the current and voltage in the main power circuit. Traditional depletion-type GaN is a cascade architecture. Under the cascade architecture, the drive signal in the existing main power circuit and digital control core is usually a positive voltage when turned on and a zero voltage when turned off. The depletion-type device is turned on when the gate voltage is zero and is turned off when the voltage is negative, that is, the depletion-type device is controlled in the opposite way to the drive signal. Therefore, the drive circuit needs to indirectly drive the depletion-type GaN to work by driving the power switching device, and cannot directly drive the depletion-type GaN to work, resulting in the depletion-type GaN being unable to fully exert its current capacity.

[0030] In order to solve the above technical defects, an embodiment of the present application provides a driving circuit, which includes: a first depletion-mode gallium nitride device, a first diode, a field effect transistor, a detection trigger module and a logic driving module.

[0031] Specifically, refer to Figure 1, the drain D of the first depletion-mode gallium nitride device D-GaN is connected to the high-voltage input power supply VDain, the source S of the first depletion-mode gallium nitride device D-GaN is connected to the drain D of the field effect transistor NMOS, and the gate G of the first depletion-mode gallium nitride device D-GaN is connected to the source S of the field effect transistor NMOS through the first diode Dsk. The input end of the detection trigger module 110 is connected to the drain D of the field effect transistor NMOS, the output end of the detection trigger module 110 is connected to the logic drive module 120, and the detection trigger module 110 is connected to the isolated power supply ISO_VCC. The input end of the logic drive module 120 is connected to the controller, the output end of the logic drive module 120 is connected to the gate G of the first depletion-mode gallium nitride device D-GaN, and the logic drive module 120 is connected to the power supply VDD and the isolated power supply ISO_VCC.

[0032] The field effect transistor NMOS is used to turn off the first depletion-mode gallium nitride device D-GaN after the first depletion-mode gallium nitride device D-GaN is powered on and the drain voltage D of the field effect transistor NMOS is greater than the first threshold value; the detection trigger module 110 is used to monitor the voltage of the isolated power supply ISO_VCC after the first depletion-mode gallium nitride device D-GaN is in the off state and the detection trigger module 120 is powered on, and if the voltage value of the isolated power supply ISO_VCC is greater than the second threshold value, a DRV signal is sent to the logic drive module 120, that is, Figure 1 The logic drive module 120 is used to respond to the DRV signal and the power supply, process the received PWM IN signal sent by the controller to obtain a PWM signal, and use the PWM signal to drive the first depletion-mode gallium nitride device D-GaN to be in an on state or an off state.

[0033] Further, refer to Figure 2 The detection trigger module 110 includes a detection trigger function unit and a switch tube K; the input end of the switch tube K1 is connected to the detection trigger function unit, the first output end of the switch tube K is connected to the source S of the first depletion-type gallium nitride device D-GaN, and the second output end of the switch tube K is connected to the isolated power supply ISO_VCC. The switch tube K is used to be in a conducting state when the voltage value of the isolated power supply is greater than the second threshold, so that the detection trigger function unit sends a DRV signal to the logic drive module.

[0034] Specifically, the logic drive module includes a first AND gate unit U1, a second AND gate unit U2, a first gate driver U3, and a second gate driver U4. Among them, the first input end of the first AND gate unit U1 is connected to the detection trigger function unit, the second input end of the first AND gate unit U1 is connected to the power supply VDD, the output end of the first AND gate unit U1 is connected to the input end of the first gate driver U3, the output end of the first gate driver U3 is respectively connected to the gate of the field effect transistor NMOS and the first input end of the second AND gate unit U2, the second input end of the second AND gate unit U2 is connected to the controller, the output end of the second AND gate unit is connected to the input end of the second gate driver U4, and the output end of the second gate driver U4 is connected to the gate G of the first depletion-mode gallium nitride device D-GaN.

[0035] It can be understood that the second gate driver U4 of the logic driver module 120 is connected to the power supply VDD and the isolated power supply ISO_VCC, and the first gate driver U3, the first AND gate unit U1 and the second AND gate unit U2 of the logic driver module 120 are connected to the power supply VDD. Among them, the first AND gate unit U1 is used to respond to the DRV signal to output a high-level signal, so that the output end of the first gate driver U3 outputs a PWM EN signal to drive the field effect transistor NMOS to be in a conductive state; the second AND gate unit U2 is used to respond to the PWM EN signal, convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver U4 outputs a PWM signal, and directly drives the first depletion-mode gallium nitride device D-GaN to be in a conductive state or an off state.

[0036] It should be noted that when both the first gate driver U3 and the second gate driver U4 output high-level signals, the high-level voltage at this time is equal to the supply voltage of the power supply VDD. The isolated power supply ISO_VCC is connected to the source S of the first depletion-mode gallium nitride device D-GaN. When the output voltage of the second gate driver U4 is high, the high-level voltage is equal to the supply voltage of the isolated power supply ISO_VC. At this time, the voltage between the gate G and the source S of the first depletion-mode gallium nitride device D-GaN is equivalent to zero voltage.

[0037] Furthermore, the driving circuit also includes a first isolated communication module 130 and a second isolated communication module 140. The first input end of the first AND gate unit U1 is connected to the detection trigger function unit through the first isolated communication module 130; the output end of the second AND gate unit U2 is connected to the input end of the second gate driver U4 through the second isolated communication module 140.

[0038] Combination Figure 3As for the above embodiments, it can be understood that when the high-voltage input power source VDain is powered on, the first depletion-mode gallium nitride device D-GaN is in the on state, the field effect transistor NMOS is in the off state, and the switch tube K is in the off state. When the drain voltage D of the field effect transistor NMOS rises to the gate threshold (first threshold) of the first depletion-mode gallium nitride device D-GaN, the first depletion-mode gallium nitride device D-GaN is in the off state. When the voltage VDD of the power supply is established and the voltage ISO_VCC of the isolated power supply reaches the second threshold, the DRV signal flips, the switch tube K is turned on, and the DRV signal is transmitted back through the first isolation communication module (ISO1) 130, so that the MOS EN signal is high level. The MOS EN signal and the voltage VDD of the power supply are output as high level after passing through the two-input AND gate (first AND gate unit U1), and then the PWM EN signal is high level through the first gate driver U3. At this time, the field effect transistor N MOS is turned on, and the PWM EN signal and the PWM IN signal are output as a PWM signal through a two-input AND gate (the first AND gate unit U1), and directly drive the first depletion-mode gallium nitride device D-GaN device after passing through the second gate driver U4.

[0039] When the high-voltage input power supply VDain loses power, the voltage VDD of the power supply is lost or the voltage ISO_VCC of the isolated power supply is lower than the second threshold, the field effect transistor NMOS and the switch tube K are in the off state, and the first depletion-mode gallium nitride device D-GaN is also in the off state. When the high-voltage input power supply VDain is less than Vth (for example, 15V), the first depletion-mode gallium nitride device D-GaN returns to the on state.

[0040] It should be noted that the field effect transistor may be an NMOS transistor, and the switch tube K may be an NMOS transistor or a PMOS transistor. The first threshold and the second threshold may be the same or different. If the first threshold and the second threshold are the same, the value range of the first threshold and the second threshold is -15 to 25V.

[0041] In another exemplary embodiment of the present application, based on the above embodiment, the driving circuit further includes a second diode and a second depletion-mode gallium nitride device connected in parallel with the first depletion-mode gallium nitride device.

[0042] Specifically, refer to Figure 4In the above embodiment, the first depletion-mode gallium nitride device D-GaN1 is connected in parallel with the second depletion-mode gallium nitride device D-GaN2, the drain D of the second depletion-mode gallium nitride device D-GaN2 is connected to the high-voltage input power supply VDain, the source S of the second depletion-mode gallium nitride device D-GaN2 is connected to the drain D of the field effect transistor NMOS, and the gate G of the second depletion-mode gallium nitride device D-GaN2 is connected to the source S of the field effect transistor NMOS through the second diode Dsk2.

[0043] It can be understood that the first depletion-mode gallium nitride device D-GaN1 and the second depletion-mode gallium nitride device D-GaN2 share a field effect transistor N MOS, an ISO_VCC detection trigger functional unit and a switch tube K. After the PWM signal passes through the second gate driver U4, the first depletion-mode gallium nitride device D-GaN1 and the second depletion-mode gallium nitride device D-GaN2 are driven simultaneously.

[0044] It should be noted that in the embodiment of the present application, only two depletion-mode gallium nitride devices are used in parallel, which is only used as an example for parallel use in a high-power system. In other embodiments, multiple devices can be connected in parallel in the same way, and the embodiment of the present application will not be repeated. In addition, the first depletion-mode gallium nitride device and the second depletion-mode gallium nitride device are both at zero voltage when in the on state and at negative voltage when in the off state.

[0045] The voltage of the isolated power supply is monitored by the detection trigger module. If the voltage value of the isolated power supply is greater than the second threshold, a DRV signal is sent to the logic drive module. The logic drive module responds to the DRV signal to be connected to the power supply, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to directly drive the first depletion-mode gallium nitride device to be in an on state or an off state. That is, the first depletion-mode gallium nitride device is directly driven by the combination of the detection trigger module and the logic drive module, and the functions of zero voltage turn-on and negative voltage turn-off are realized without changing the control logic of the first depletion-mode gallium nitride device, so that the strong current-carrying capacity of the first depletion-mode gallium nitride device can be fully utilized.

[0046] Based on the same inventive concept, the embodiment of the present application also provides a driving device for implementing the driving circuit involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above driving circuit, so the specific limitations in one or more driving device embodiments provided below can refer to the above limitations on the driving circuit, and will not be repeated here.

[0047] In an exemplary embodiment, Figure 5As shown, a schematic diagram of the structure of a driving device is provided. The driving device is applied to a power electronic system, and the driving device includes a driving circuit, which includes: a first depletion-mode gallium nitride device, a first diode, a field effect transistor, a detection trigger module, and a logic driving module.

[0048] Specifically, the drain of the first depletion-mode gallium nitride device is connected to the high-voltage input power supply, the source of the first depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the first depletion-mode gallium nitride device is connected to the source of the field effect transistor through a first diode; the input end of the detection trigger module is connected to the drain of the field effect transistor, the output end of the detection trigger module is connected to the logic drive module, and the detection trigger module is connected to an isolated power supply; the input end of the logic drive module is connected to the controller, the output end of the logic drive module is connected to the gate of the first depletion-mode gallium nitride device, and the logic drive module is connected to a power supply and an isolated power supply.

[0049] The field effect transistor is used to turn off the first depletion-mode gallium nitride device after the first depletion-mode gallium nitride device is powered on and the drain voltage of the field effect transistor is greater than the first threshold value; the detection trigger module is used to monitor the voltage of the isolated power supply after the first depletion-mode gallium nitride device is in the off state and the detection trigger module is powered on, and if the voltage value of the isolated power supply is greater than the second threshold value, send a DRV signal to the logic drive module; the logic drive module is used to respond to the DRV signal and conduct with the power supply, process the received PWM IN signal sent by the controller to obtain a PWM signal, and use the PWM signal to drive the first depletion-mode gallium nitride device to be in the on state or the off state.

[0050] As an optional implementation, the detection trigger module includes a detection trigger functional unit and a switch tube; the input end of the switch tube is connected to the detection trigger functional unit, the first output end of the switch tube is connected to the source of the first depletion-mode gallium nitride device, and the second output end of the switch tube is connected to the isolated power supply; the switch tube is used to be in an on state when the voltage value of the isolated power supply is greater than a second threshold, so that the detection trigger functional unit sends a DRV signal to the logic drive module.

[0051] As an optional implementation, the logic driving module includes: a first AND gate unit, a second AND gate unit, a first gate driver, and a second gate driver; the first input end of the first AND gate unit is connected to the detection trigger function unit, the second input end of the first AND gate unit is connected to the power supply, the output end of the first AND gate unit is connected to the input end of the first gate driver, the output end of the first gate driver is respectively connected to the gate of the field effect transistor and the first input end of the second AND gate unit, the second input end of the second AND gate unit is connected to the controller, the output end of the second AND gate unit is connected to the input end of the second gate driver, and the output end of the second gate driver is connected to the gate of the first depletion-type gallium nitride device, wherein the first AND gate unit is used to respond to the DRV signal to output a high-level signal, so that the output end of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in a conducting state; the second AND gate unit is used to respond to the PWM EN signal to convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs a PWM signal to directly drive the first depletion-type gallium nitride device to be in a conducting state or an off state.

[0052] As an optional embodiment, the above-mentioned driving circuit also includes a first isolated communication module and a second isolated communication module; the first input end of the first AND gate unit is connected to the detection trigger function unit through the first isolated communication module; the output end of the second AND gate unit is connected to the input end of the second gate driver through the second isolated communication module.

[0053] As an optional implementation, the driving circuit further includes a second diode and a second depletion-mode gallium nitride device connected in parallel with the first depletion-mode gallium nitride device; wherein the drain of the second depletion-mode gallium nitride device is connected to the high-voltage input power supply, the source of the second depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the second depletion-mode gallium nitride device is connected to the source of the field effect transistor through the second diode.

[0054] As an optional implementation, the first depletion-mode gallium nitride device and the second depletion-mode gallium nitride device are both at zero voltage when in an on state and at a negative voltage when in an off state.

[0055] As an optional implementation, the field effect transistor is an NMOS tube, and the switch tube is an NMOS tube or a PMOS tube.

[0056] Among them, by adopting the above-mentioned driving device, the first depletion-mode gallium nitride device can be directly driven by combining the detection trigger module and the logic driving module, and the functions of zero voltage turn-on and negative voltage turn-off can be realized without changing the control logic of the first depletion-mode gallium nitride device, thereby giving full play to the strong current-carrying capacity of the first depletion-mode gallium nitride device.

[0057] Based on the same inventive concept, the embodiment of the present application also provides a driving method for implementing the driving circuit involved above. The implementation solution provided by the method to solve the problem is similar to the implementation solution recorded in the above-mentioned driving, so the specific limitations in one or more driving method embodiments provided below can refer to the above-mentioned limitations on the driving circuit, and will not be repeated here.

[0058] In an exemplary embodiment, Figure 6 As shown, a schematic flow chart of a driving method is provided. The driving method may include steps S610 to S630, specifically:

[0059] Step S610, after the first depletion-mode gallium nitride device is powered on, the field effect transistor has a drain voltage greater than a first threshold, so that the first depletion-mode gallium nitride device is in an off state;

[0060] Step S620: after the first depletion-mode gallium nitride device is in the off state and the detection trigger module is powered on, the detection trigger module monitors the voltage of the isolated power supply, and sends a DRV signal to the logic drive module if the voltage value of the isolated power supply is greater than a second threshold;

[0061] In step S630, the logic driving module is connected to the power supply in response to the DRV signal, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to drive the first depletion-mode gallium nitride device to be in an on state or an off state.

[0062] The above step S630 may further specifically include: the first AND gate unit outputs a high-level signal in response to the DRV signal, so that the output end of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in an on state; the second AND gate unit is used to respond to the PWM EN signal to convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs a PWM signal to directly drive the first depletion-mode gallium nitride device to be in an on state or an off state.

[0063] The voltage of the isolated power supply is monitored by the detection trigger module. If the voltage value of the isolated power supply is greater than the second threshold, a DRV signal is sent to the logic drive module. The logic drive module responds to the DRV signal to be connected to the power supply, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to directly drive the first depletion-mode gallium nitride device to be in an on state or an off state. That is, the first depletion-mode gallium nitride device is directly driven by the combination of the detection trigger module and the logic drive module, and the functions of zero voltage turn-on and negative voltage turn-off are realized without changing the control logic of the first depletion-mode gallium nitride device, so that the strong current-carrying capacity of the first depletion-mode gallium nitride device can be fully utilized.

[0064] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A driving circuit, characterized in that: The driving circuit includes: a first depletion-mode gallium nitride device, a first diode, a field effect transistor, a detection trigger module and a logic driving module; The drain of the first depletion-mode gallium nitride device is connected to a high-voltage input power supply, the source of the first depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the first depletion-mode gallium nitride device is connected to the source of the field effect transistor through the first diode; The detection trigger module includes a detection trigger function unit and a switch tube; the input end of the switch tube is connected to the detection trigger function unit, and the first output end of the switch tube is connected to the source of the first depletion-mode gallium nitride device; the second output end of the switch tube is connected to an isolated power supply; the detection trigger function unit is connected to the logic drive module; The input end of the logic driving module is connected to the controller, the output end of the logic driving module is connected to the gate of the first depletion-mode gallium nitride device, and the logic driving module is connected to a power supply and the isolated power supply; wherein, The field effect transistor is used to turn off the first depletion-mode gallium nitride device after the first depletion-mode gallium nitride device is powered on and the drain voltage of the field effect transistor is greater than a first threshold; The detection trigger module is used to monitor the voltage of the isolated power supply based on the detection trigger function unit after the first depletion-mode gallium nitride device is in the off state and the detection trigger function unit is powered on. If the voltage value of the isolated power supply is greater than a second threshold, the switch tube is in the on state, and the detection trigger function unit sends a DRV signal to the logic drive module; The logic driving module is used to respond to the DRV signal and be connected to the power supply, process the received PWM IN signal sent by the controller to obtain a PWM signal, and use the PWM signal to drive the first depletion-mode gallium nitride device to be in an on state or an off state.

2. The driving circuit according to claim 1, characterized in that: The logic driving module includes: a first AND gate unit, a second AND gate unit, a first gate driver, and a second gate driver; The first input end of the first AND gate unit is connected to the detection trigger function unit, the second input end of the first AND gate unit is connected to the power supply, the output end of the first AND gate unit is connected to the input end of the first gate driver, the output end of the first gate driver is respectively connected to the gate of the field effect transistor and the first input end of the second AND gate unit, the second input end of the second AND gate unit is connected to the controller, the output end of the second AND gate unit is connected to the input end of the second gate driver, and the output end of the second gate driver is connected to the gate of the first depletion-mode gallium nitride device, wherein, The first AND gate unit is used to output a high level signal in response to the DRV signal, so that the output end of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in a conducting state; The second AND gate unit is used to respond to the PWM EN signal and convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs the PWM signal to directly drive the first depletion-mode gallium nitride device to be in an on state or an off state.

3. The driving circuit according to claim 2, characterized in that: The driving circuit also includes a first isolated communication module and a second isolated communication module; The first input end of the first AND gate unit is connected to the detection trigger function unit through the first isolation communication module; the output end of the second AND gate unit is connected to the input end of the second gate driver through the second isolation communication module.

4. The driving circuit according to claim 2, characterized in that: The driving circuit further includes a second diode and a second depletion-mode gallium nitride device connected in parallel with the first depletion-mode gallium nitride device; wherein, The drain of the second depletion-mode gallium nitride device is connected to the high-voltage input power supply, the source of the second depletion-mode gallium nitride device is connected to the drain of the field effect transistor, and the gate of the second depletion-mode gallium nitride device is connected to the source of the field effect transistor through the second diode.

5. The driving circuit according to claim 4, characterized in that: The first depletion-mode gallium nitride device and the second depletion-mode gallium nitride device both have a zero voltage when in an on state and a negative voltage when in an off state.

6. The driving circuit according to claim 1, characterized in that: The field effect transistor is an NMOS tube, and the switch tube is an NMOS tube or a PMOS tube.

7. A driving device, characterized in that: The driving device comprises a driving circuit as described in any one of claims 1 to 5, and the driving device is applied to a power electronic system.

8. A driving method, characterized in that: Applied to the driving circuit as described in any one of claims 1 to 6 above, the driving method comprises: After the first depletion-mode gallium nitride device is powered on, the field effect transistor has a drain voltage greater than a first threshold, so that the first depletion-mode gallium nitride device is in an off state; After the first depletion-mode gallium nitride device is in the off state and the detection trigger function unit is powered on, the detection trigger module monitors the voltage of the isolated power supply based on the detection trigger function unit. If the voltage value of the isolated power supply is greater than a second threshold, the switch tube is in the on state, and the detection trigger function unit sends a DRV signal to the logic drive module; The logic driving module is connected to the power supply in response to the DRV signal, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and uses the PWM signal to drive the first depletion-mode gallium nitride device to be in an on state or an off state.

9. The driving method according to claim 8, characterized in that: The logic driving module is connected to the power supply in response to the DRV signal, processes the received PWM IN signal sent by the controller to obtain a PWM signal, and drives the first depletion-mode gallium nitride device to be in an on state or an off state by using the PWM signal, including: The first AND gate unit outputs a high level signal in response to the DRV signal, so that the output terminal of the first gate driver outputs a PWM EN signal to drive the field effect transistor to be in a conducting state; The second AND gate unit is used to respond to the PWM EN signal and convert the PWM IN signal input by the controller into a PWM signal, so that the output end of the second gate driver outputs the PWM signal to directly drive the first depletion-mode gallium nitride device to be in an on state or an off state.

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