A gallium nitride device drive power supply regulation circuit and method

Abstract

This invention discloses a gallium nitride (GaN) device drive power supply regulation circuit and method. The circuit comprises four modules: a rectangular wave generation module, a filtering module, a gate drive module, and a power module. The rectangular wave generation module uses a low-cost 555 timer chip to generate a rectangular wave below 2MHz. The filtering module converts the rectangular wave into a sufficient DC current and, in conjunction with an operational amplifier, provides a certain current. The gate drive module is powered by the DC current generated by the filtering module; adjusting the resistor and capacitor values ​​allows for flexible adjustment of the duty cycle and switching frequency of the GaN transistor gate drive power supply. The power module represents the specific circuitry used in the GaN transistor application. This invention utilizes a low-cost 555 timer chip to achieve flexible regulation of the gate drive power supply, suppressing the degradation of parameters such as threshold voltage and on-resistance of the GaN transistor under different operating modes, and improving the stability and reliability of the GaN transistor during circuit operation.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor devices and relates to a gallium nitride device driving power supply regulation circuit and method. Background Technology

[0002] Gallium nitride (GaN) power devices have been widely used in power conversion circuits due to their advantages of high frequency, high voltage, and high temperature resistance. Currently, there are two main types of commercially available normally-off GaN high electron mobility transistors: cascode switch and p-GaN gate HEMT. Among them, the p-GaN gate HEMT has lower parasitic inductance and is more widely used.

[0003] However, defects introduced during material growth and device fabrication cause threshold voltage drift and on-resistance degradation in p-GaN gate HEMTs under drain and gate voltage stress, reducing the performance of the p-GaN gate HEMT and the circuit system. Therefore, gallium nitride devices require different gate drive voltages to suppress performance degradation when operating under different drain voltages, gate voltage stresses, and temperatures. Furthermore, different brands of gallium nitride transistors have different threshold voltages and gate drive voltage ranges. Therefore, it is necessary to design a gallium nitride device drive power supply regulation circuit to meet the driving requirements of transistors from different brands and operating modes, maximizing the advantages of gallium nitride transistors in terms of high frequency, high voltage resistance, and low on-resistance. Summary of the Invention

[0004] This invention addresses the unstable threshold voltage of p-GaN gate HEMTs by proposing a driving strategy that modulates the driving voltage of p-GaN gate HEMTs under different operating conditions. A driving power supply regulation circuit and method for gallium nitride devices are disclosed. This invention effectively suppresses the threshold voltage drift problem of gallium nitride transistors, prevents device performance degradation, and improves the stability and reliability of the device when operating in high-frequency circuits. Its key feature is that it does not use microcontrollers, DSPs, or other digital chips, and requires no code programming. It achieves a low-cost, high-precision, and easily adjustable driving power supply based on analog circuits.

[0005] The first aspect of this invention aims to provide a gallium nitride (GaN) device drive power supply regulation circuit. This circuit comprises four modules: a rectangular wave generation module, a filtering module, a gate drive module, and a power module. The rectangular wave generation module uses a first-stage 555 timer chip to generate a rectangular wave below 2MHz. The filtering module converts the rectangular wave into DC current and, in conjunction with an operational amplifier, increases the output current while maintaining the DC voltage value. The gate drive module uses the DC current generated by the filtering module as its power supply and adjusts the duty cycle and switching frequency of the GaN transistor gate drive signal by adjusting the values ​​of resistors and capacitors provided in the gate drive module. The power module is a power application circuit including a GaN transistor, and the gate drive signal of the GaN transistor is adjusted through the gate drive module.

[0006] Furthermore, the rectangular wave generation module includes a first-stage 555 timer chip, resistors R1, R2, and R3, diodes D1 and D2, and capacitors C1 and C2. The common connection point of resistors R1 and R2 is connected to pin 7 of the first-stage 555 timer chip and the anode of diode D1. The other end of resistor R1 is connected to pins 4 and 8 of the first-stage 555 timer chip and V... CC The resistor R2 is connected to the cathode of diode D2. The anode of diode D2 is connected to one end of resistor R3 and pins 2 and 6 of the first-stage 555 chip. The other end of resistor R3 is connected to the cathode of diode D1. The common connection point of capacitors C1 and C2 is connected to pin 1 of the first-stage 555 chip and grounded. The other end of capacitor C1 is connected to the sliding end of resistor R3. The other end of capacitor C2 is connected to pin 5 of the first-stage 555 chip. Pin 3 of the first-stage 555 chip is connected to the filter module.

[0007] The rectangular wave generation module uses a first-stage 555 chip operating in multi-harmonic oscillation mode to output a rectangular wave. Resistors R1, R2, R3 and capacitor C1 are used to control the period and duty cycle of the rectangular wave, and diodes D1 and D2 improve the flexibility of duty cycle adjustment.

[0008] Furthermore, the filter module includes resistors R4 and R5, inductor L1, capacitor C3, and operational amplifier. One end of inductor L1 is connected to one end of resistor R4, and the other end of inductor L1 is connected to capacitor C3, one end of resistor R5, and the non-inverting input of operational amplifier. The other ends of capacitor C3 and resistor R5 are connected to ground. The inverting input and output of operational amplifier are connected to the gate drive module, and the other end of resistor R4 is connected to pin 3 of the first-stage 555 chip.

[0009] Furthermore, the gate drive module includes a second-stage 555 chip, resistors R6, R7, and R8, diodes D3 and D4, and capacitors C4 and C5. The common connection point of resistors R6 and R7 is connected to pin 7 of the second-stage 555 chip and the anode of diode D3. The other end of resistor R6 is connected to pins 4 and 8 of the second-stage 555 chip and the output of the operational amplifier in the filter module. The other end of resistor R7 is connected to the cathode of diode D4. The anode of diode D4 is connected to one end of resistor R8 and pins 2 and 6 of the second-stage 555 chip. The other end of resistor R8 is connected to the cathode of diode D3. The common connection point of capacitors C4 and C5 is connected to pin 1 of the second-stage 555 chip and grounded. The other end of capacitor C4 is connected to the sliding contact of resistor R8. The other end of capacitor C5 is connected to pin 5 of the second-stage 555 chip. The drive chip is connected to the second-stage 555 chip and the power module.

[0010] The gate drive module uses the DC power output from the filter module as its power supply. The second-stage 555 chip in this module generates the control signals required by the gate drive chip. Depending on the experimental requirements, the second-stage 555 chip can be set to operate in multivibrator mode, monostable mode, or trigger mode. When the second-stage 555 chip operates in multivibrator mode, resistors R6, R7, R8 and capacitor C4 are used to control the period and duty cycle of the drive waveform, and the output drive waveform meets the design requirements. The gate drive chip is used to amplify the output current capability of the drive waveform to control the turn-on and turn-off of the subsequent gallium nitride transistor.

[0011] Furthermore, the power module includes a resistor R9 and a gallium nitride transistor (GaN) under test. The resistor R9 is connected to the drain of the GaN transistor, and the source and gate of the GaN transistor are connected to the driver chip.

[0012] A second aspect of this invention provides a method for regulating the driving power supply of a gallium nitride (GaN) device, implemented using the GaN device driving power supply regulation circuit described in this invention, comprising the following steps:

[0013] The first step is to determine the optimal gate drive voltage of the gallium nitride transistor. First, determine the actual operating state of the transistor. Then, based on the device datasheet or the dynamic transfer curve of the actual test device, obtain the threshold voltage drift of the gallium nitride device, and then adjust the gate drive voltage according to the threshold voltage drift.

[0014] The second step is to generate the DC power required for driving. First, set the resistance and capacitance values ​​of the rectangular wave generation module to adjust the duty cycle and frequency of the rectangular wave. Then, set the resistance, inductance, and capacitance values ​​of the filter module to convert the rectangular wave into DC power. Then, use the voltage follower function of the operational amplifier to convert the DC power into a load-carrying DC power and use the DC power to power the second-stage 555 chip and the driver chip.

[0015] The third step is to output various pulse waveforms that meet the requirements and connect them to the gate of the gallium nitride transistor under test as driving signals. The second-stage 555 chip is used to set the chip's operating mode and determine the resistance and capacitance values ​​of the gate drive module, thereby obtaining various pulse signals to control the gate drive chip.

[0016] Beneficial effects:

[0017] 1. This invention achieves low-cost, high-precision drive voltage regulation based on analog circuits.

[0018] 2. This invention can suppress the adverse effects of threshold voltage drift and on-resistance degradation in gallium nitride transistors, thereby improving the stability of gallium nitride transistors when they are working in circuits. Attached Figure Description

[0019] The invention will be better understood from the following description, which relates to a preferred embodiment given by way of non-limiting example and explained with reference to the accompanying schematic diagram, wherein:

[0020] Figure 1 This is a schematic diagram of a gallium nitride transistor structure.

[0021] Figure 2 This is a schematic diagram of the pulse voltage simulating the drain voltage stress of a gallium nitride transistor during circuit operation.

[0022] Figure 3 This is a schematic diagram of the dynamic transfer curves of a gallium nitride transistor under different drain voltage stresses.

[0023] Figure 4 It is the threshold voltage value of a gallium nitride transistor when subjected to different drain voltage stresses.

[0024] Figure 5 This is a schematic diagram of the power supply regulation circuit for gallium nitride devices.

[0025] Figure 6 This is a flowchart of the method for regulating the driving power supply of gallium nitride devices.

[0026] Figure 7 This is a reference circuit when the transistor is driven by a 6V gate voltage.

[0027] Figure 8 It was simulated using Cadence software. Figure 7 The waveforms of key nodes in the circuit at a steady state of 60ms. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0029] Specifically, in the description of this application, the terms "one end," "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. Unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0030] like Figure 1 As shown, the structure of a gallium nitride (GaN) transistor, from bottom to top, includes a substrate, a gallium nitride buffer layer, a two-dimensional electron gas (2D) channel layer, a barrier layer, a dielectric layer, a gate, a source, a gate, and a drain. The substrate serves as the supporting material for the GaN transistor. The gallium nitride buffer layer reduces the diffusion of the 2D electron gas towards the substrate. The barrier layer polarizes the 2D electron gas generated in the channel layer, and the dielectric layer regulates the concentration of the 2D electron gas below the gate. The source, drain, and gate are the three electrodes of the GaN transistor. When the GaN transistor operates as a switch, the gate voltage controls the opening and closing of the 2D electron gas channel below the gate. During the switching process, the gate and drain of the GaN transistor are continuously subjected to pulse voltage stress. Due to the high defect density of the gate dielectric layer, carrier trapping and detrapping processes occur in the gate dielectric layer when the GaN transistor operates as a switch, leading to instability in the transistor's threshold voltage. Currently, it is difficult to reduce the defect density of the gate dielectric layer and solve the threshold voltage drift problem in the manufacturing process.

[0031] Figure 2 This is a schematic diagram simulating the pulse voltage of a gallium nitride (GaN) transistor under drain voltage stress during circuit operation. In the off state, the drain voltage is the bus voltage. Depending on the circuit experiment requirements and the transistor's rated drain voltage, the drain voltage stress the transistor experiences may range from 0 to several kilovolts. Existing GaN transistors have different gate drive voltage ranges, and when the transistor is subjected to voltage stress, the threshold voltage drifts. Therefore, different gate voltages are required to drive the transistor to achieve optimal operating performance; the gate drive voltage is typically between 5 and 8V. Figure 2As shown, firstly, a drain voltage stress of a certain duration is applied to the transistor according to its operating state in the circuit. Then, the transistor drain voltage is switched to the test voltage, typically 0.1–1V. Next, a pulse voltage sequence is applied to the transistor gate to measure the transistor's "dynamic transfer curve." The gate voltage is an increasing pulse voltage, and the data sampling points are from the plateau region after the pulse signal stabilizes (at 75% of the pulse signal). Analyzing the transistor's dynamic transfer curve reveals key parameters such as the transistor's threshold voltage and on-resistance.

[0032] Figure 3 This is a schematic diagram of the dynamic transfer curves of a gallium nitride transistor under different drain voltage stresses. Depending on experimental needs, the degradation of transistor dynamic parameters under different drain voltage stress durations can be studied. Figure 3 The voltage stress time in the schematic diagram is 1 second. The constant current method is used to extract the threshold voltage, taking the gate voltage at which the current equals 1 mA in the dynamic transfer curve as the threshold voltage. It can be seen that as the drain voltage stress increases, the tested dynamic transfer characteristic curve gradually shifts to the right, and the threshold voltage drift also increases. Subsequently, the threshold voltage drift is compensated for by adjusting the gate drive voltage.

[0033] Figure 4 It is the threshold voltage value of a gallium nitride transistor after being subjected to different drain voltage stresses. According to Figure 2 The test method shown and Figure 3 The standard for extracting the threshold voltage is shown. Data shows that for a power gallium nitride transistor with a rated drain voltage of 650V, when its drain voltage stress increases from 0V to 400V, its threshold voltage generally exhibits a characteristic of first increasing and then leveling off. When the drain of the gallium nitride transistor is subjected to a voltage stress of 100V, the threshold voltage drift is close to 0.7V. An increase in the threshold voltage makes the transistor more "difficult to turn on," meaning that when a fixed drive voltage is used to drive the transistor gate, the device's on-resistance increases, reducing the efficiency of the transistor and the circuit system and leading to more heat generation. To improve transistor performance, the transistor gate drive voltage can be dynamically adjusted based on the transistor's operating state and performance degradation parameters within the circuit system.

[0034] Figure 5 This is a schematic diagram of the power supply control circuit for gallium nitride (GaN) devices. The power supply consists of four modules: a rectangular wave generation module, a filtering module, a gate drive module, and a power module.

[0035] The rectangular wave generation module uses a low-cost 555 timer chip to generate rectangular waves with frequencies below 2MHz in an "analog" manner. It includes a first-stage 555 timer chip, resistors R1, R2, and R3, diodes D1 and D2, and capacitors C1 and C2. The common connection point of resistors R1 and R2 is connected to pin 7 of the first-stage 555 timer chip and the anode of diode D1. The other end of resistor R1 is connected to pins 4 and 8 of the first-stage 555 timer chip and V... CC The circuit is as follows: the other end of resistor R2 is connected to the cathode of diode D2; the anode of diode D2 is connected to one end of resistor R3 and pins 2 and 6 of the first-stage 555 timer chip; the other end of resistor R3 is connected to the cathode of diode D1; the common connection point of capacitors C1 and C2 is connected to pin 1 of the first-stage 555 timer chip and grounded; the other end of capacitor C1 is connected to the sliding contact of resistor R3; the other end of capacitor C2 is connected to pin 5 of the first-stage 555 timer chip; and pin 3 of the first-stage 555 timer chip is connected to the filter module. The first-stage 555 timer chip operates in multi-harmonic oscillation mode, and the period and duty cycle of the rectangular wave are controlled by resistors R1, R2, R3, and capacitor C1. Diodes D1 and D2 are used to control the charging and discharging path of capacitor C1, thereby improving the flexibility of duty cycle adjustment. R1 and R2 act as current-limiting resistors; when the value of variable resistor R3 is small, the circuit current is limited to prevent the first-stage 555 timer chip from burning out. The first-stage 555 chip has pin 3 as its output point, producing a rectangular wave V1 that meets the requirements. The high-level duration T of the rectangular wave... ON =Ln2×(R1+R 3左 )×C1, Duration T of low level of rectangular wave OFF =Ln2×(R2+R 3右 )×C1, period T=T ON +T OFF =Ln2×(R1+R2+R3)×C1, frequency f=1 / T=1 / [Ln2×(R1+R2+R3)×C1], duty cycle D=T ON / (T ON +T OFF )=(R1+R 3左 The duty cycle D is calculated as (R1 + R2 + R3). Since the duty cycle D depends only on resistors R1, R2, and R3, while the rectangular wave frequency depends on resistors R1, R2, and R3 as well as capacitor C1, the parameters of resistors R1, R2, and R3 can be determined first based on the duty cycle, and then the parameters of capacitor C1 can be determined based on the target frequency of the rectangular wave.

[0036] The filtering module is an RLC second-order low-pass filter, comprising resistors R4 and R5, inductor L1, capacitor C3, and an operational amplifier. One end of inductor L1 is connected to one end of resistor R4. The other end of inductor L1 is connected to capacitor C3, one end of resistor R5, and the non-inverting input of the operational amplifier. The other ends of capacitor C3 and resistor R5 are connected to ground. The inverting input and output of the operational amplifier are connected to the gate driver module. The other end of resistor R4 is connected to pin 3 of the first-stage 555 timer chip. In this invention, the filtering module is essentially an LC filter circuit, and resistor R4 can be used to control the current spikes in the module. In specific applications, appropriate parameters for resistors R4 and R5, inductor L1, and capacitor C3 should be selected according to experimental requirements. This filtering module first converts the rectangular wave signal into DC current, and then, using the voltage follower function of the operational amplifier, increases the load-carrying capacity (outputs a larger current) while maintaining the DC voltage value.

[0037] The gate drive module includes a second-stage 555 timer chip, resistors R6, R7, and R8, diodes D3 and D4, and capacitors C4 and C5. The common connection point of resistors R6 and R7 is connected to pin 7 of the second-stage 555 timer chip and the anode of diode D3. The other end of resistor R6 is connected to pins 4 and 8 of the second-stage 555 timer chip and the output of the operational amplifier in the filter module. The other end of resistor R7 is connected to the cathode of diode D4. The anode of diode D4 is connected to one end of resistor R8 and pins 2 and 6 of the second-stage 555 timer chip. The other end of resistor R8 is connected to the cathode of diode D3. The common connection point of capacitors C4 and C5 is connected to pin 1 of the second-stage 555 timer chip and grounded. The other end of capacitor C4 is connected to the sliding contact of resistor R8. The other end of capacitor C5 is connected to pin 5 of the second-stage 555 timer chip. The drive chip is connected to the second-stage 555 timer chip and the power module. This invention uses DC power generated by a filter module as the power supply for the second-stage 555 timer chip and the gate driver chip. The second-stage 555 timer chip generates pulse signals, and the gate driver chip converts these pulse signals into a pulse voltage with load-carrying capacity, which is then used as the gate drive voltage for the transistor. The second-stage 555 timer chip can be configured to operate in multivibrator mode, monostable mode, or trigger mode, depending on experimental needs. When the second-stage 555 timer chip operates in multivibrator mode, resistors R6, R7, and R8, and capacitor C4 are used to control the period and duty cycle of the rectangular wave. Diodes D3 and D4 control the charging and discharging paths of capacitor C4, improving the flexibility of duty cycle adjustment. V3 serves as the output point, providing a rectangular wave that meets design requirements.

[0038] The power module represents the "power circuit" when the gallium nitride transistor is actually working. The power module includes a resistor R9 and the gallium nitride transistor under test. The resistor R9 is connected to the drain of the gallium nitride transistor, and the source and gate of the gallium nitride transistor are connected to the driver chip. Figure 5 A simple inverter circuit is used as an example of the application scenario. Simulation verification shows that when the rectangular wave generation module outputs a 100kHz rectangular wave, the filtering module can filter the rectangular wave to generate a DC current with low voltage ripple (within 0.05V) within 0.1s. Further increasing the operating frequency of the rectangular wave can reduce the DC ripple of the filtering module and further reduce the inductor and capacitor values ​​of the filtering module. However, high-frequency rectangular waves will introduce greater electromagnetic interference (EMI). The output rectangular wave frequency can be flexibly designed according to actual needs.

[0039] Figure 6 This is a flowchart of the gallium nitride (GaN) device drive power supply regulation method. The first step is to determine the target gate drive voltage of the GaN transistor. First, determine the actual operating state of the transistor (e.g., the drain voltage stress on the transistor). Then, based on the device datasheet or the dynamic transfer curve of the actual tested device, determine the threshold voltage drift of the GaN device. Finally, determine the gate drive voltage to be compensated and the target drive voltage based on the threshold voltage drift. The second step is to generate the adjustable, load-carrying DC voltage required for driving. First, set the resistor and capacitor values ​​of the "rectangular wave generation module" to adjust the duty cycle and frequency of the rectangular wave. Then, set the resistor, inductor, and capacitor values ​​of the "filter module" to filter the rectangular wave and convert it into DC power. The voltage follower function of the operational amplifier then converts this DC power into a load-carrying (capable of outputting a certain current) DC power, which powers the second-stage 555 timer chip and the driver chip. The third step is to output various pulse waveforms that meet the requirements and connect them to the gate of the gallium nitride transistor under test as driving signals. First, the second-stage 555 timer chip is used to set the chip's operating mode (multi-harmonic oscillation, monostable, etc.) and determine the resistance and capacitance values ​​of the gate drive module, thereby obtaining various pulse control signals. Then, the pulse control signal is amplified by the driver chip to obtain an adjustable gate voltage drive power supply, which is used to drive the transistor gate.

[0040] Example

[0041] Figure 7 This is a reference circuit driven by a 6V gate voltage. The selected components and their numerical parameters are already available. Figure 7The diagram shows the voltages at eight key nodes, which will not be elaborated upon here. The first-stage 555 chip operates in multi-harmonic resonant mode. V1 measures the voltage at the capacitor, and V2 measures its output voltage. V3 represents the signal after the current-limiting resistor flows through the filter module, and V4 represents the voltage signal after the inductor and capacitor of the filter module. V5 represents the voltage output by the op-amp following V4. This voltage is output by the op-amp and has a certain load-carrying and output current capability. V6 is the voltage at the capacitor of the second-stage 555 chip. In this example, the second-stage 555 chip operates in multi-harmonic resonant mode and outputs a rectangular wave at pin 3. This rectangular wave signal is transformed into a pulse voltage V7 with "load-carrying capability (can output a large current)" after passing through the "driver chip". Connect V7 to the gate of the gallium nitride transistor in the subsequent inverter circuit. The drain of the gallium nitride transistor is connected in series with a 1kΩ resistor to the high-voltage power supply. V8 represents the drain voltage of the gallium nitride transistor.

[0042] Figure 8 It was simulated using Cadence software. Figure 7 The waveforms at key nodes of the circuit in steady state at 60ms are shown. Figure 7 The circuit shows the voltages at eight key nodes. For a 555 timer chip operating in multi-harmonic mode, the capacitor voltage fluctuates between 1 / 3 and 2 / 3 of the supply voltage. Since the first-stage 555 chip's supply voltage is 9V, the voltage V1 at the capacitor of the first-stage 555 chip is an exponential wave of 3-6V. V2 is high during the V1 increase phase and low during the V1 decrease phase. V3 is the waveform of the rectangular wave signal passing through the current-limiting resistor but not through the inductor and capacitor. V4 is the signal after the rectangular wave signal has passed through the filtering module. Figure 8 It can be seen that the ripple of the filtered DC voltage V4 is within 0.05V. The operational amplifier operates in voltage follower mode, following voltage V4 to output voltage V5. Voltage V5 has a certain output current and load-driving capability. Voltage V5 supplies power to the subsequent 555 timer chip and indirectly determines the high level of the rectangular wave output by the subsequent 555 timer chip. Although the 555 timer chip is not a "rail-to-rail" type, the voltage difference between the supply voltage and the high level of the output voltage is a constant. Therefore, the supply voltage required by the 555 timer chip can be deduced from the target high level of the output voltage. The second-stage 555 timer chip acts as a gate driver chip, and its operating mode can be selected according to experimental needs. Figure 7 In the example circuit, the second-stage 555 timer chip also operates in multi-harmonic resonant mode. V6 is the voltage across the capacitor. V7 is the rectangular wave signal output by the second-stage 555 timer chip. The drain of the gallium nitride transistor is connected to a high-voltage power supply via a resistor, forming an inverter circuit. The inverter circuit is used to verify whether the proposed drive power supply can drive the gate of the gallium nitride transistor normally. V8 is the drain voltage of the gallium nitride transistor.

[0043] This invention relates to a gallium nitride (GaN) device drive power supply regulation circuit and method, which enables low-cost, high-precision drive voltage regulation based on analog circuitry. Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for regulating the driving power supply of a gallium nitride device, characterized in that: This is achieved through a gallium nitride (GaN) device drive power supply regulation circuit, which comprises four modules: a rectangular wave generation module, a filtering module, a gate drive module, and a power module. The rectangular wave generation module uses a first-stage 555 timer chip to generate a rectangular wave below 2 MHz. The filtering module converts the rectangular wave into DC current and, in conjunction with an operational amplifier, increases the output current while maintaining the DC voltage value. The gate drive module uses the DC current generated by the filtering module as its power supply, and adjusts the duty cycle and switching frequency of the GaN transistor gate drive signal by adjusting the values ​​of resistors and capacitors provided in the gate drive module. The power module is a power application circuit including the GaN transistor; the gate drive signal of the GaN transistor is adjusted through the gate drive module. The method includes the following steps: The first step is to determine the optimal gate drive voltage of the gallium nitride transistor. First, determine the actual operating state of the transistor. Then, based on the device datasheet or the dynamic transfer curve of the actual test device, obtain the threshold voltage drift of the gallium nitride device, and then adjust the gate drive voltage according to the threshold voltage drift. The second step is to generate the DC power required for driving. First, set the resistance and capacitance values ​​of the rectangular wave generation module to adjust the duty cycle and frequency of the rectangular wave. Then, set the resistance, inductance, and capacitance values ​​of the filter module to convert the rectangular wave into DC power. Then, use the voltage follower function of the operational amplifier to convert the DC power into a load-carrying DC power and use the DC power to power the second-stage 555 chip and the driver chip. The third step is to output various pulse waveforms that meet the requirements and connect them to the gate of the gallium nitride transistor under test as driving signals. The second-stage 555 chip is used to set the chip's operating mode and determine the resistance and capacitance values ​​of the gate drive module, thereby obtaining various pulse signals to control the gate drive chip.

2. The gallium nitride device driving power supply regulation method according to claim 1, characterized in that: The rectangular wave generation module includes a first-stage 555 timer chip and resistors. R 1. R 2. R 3. Diode D 1. D 2. Capacitor C 1. C 2, where the resistance R 1 and R The common connection point of the two phases is connected to pin 7 of the first-stage 555 chip and the diode. D The anode of 1 is connected, and the resistance is... R The other end of 1 connects to pins 4 and 8 of the first-stage 555 chip and... V CC Connected, resistance R The other end of 2 is connected to the diode. D The cathodes of diodes 2 are connected together. D 2 Anode and resistance R One end of 3 is connected to pins 2 and 6 of the first-stage 555 chip, and the resistor... R The other end of 3 is connected to the diode. D The cathode of 1 is connected, and the capacitor C 1 and C The common connection point of the two phases is connected to pin 1 of the first-stage 555 chip and grounded, capacitor C The other end of 1 is connected to the resistor. R Connect the sliding end of 3 to the capacitor. C The other end of 2 is connected to pin 5 of the first-stage 555 chip, and pin 3 of the first-stage 555 chip is connected to the filter module.

3. The method for regulating the driving power supply of a gallium nitride device according to claim 2, characterized in that: The rectangular wave generation module uses a first-stage 555 timer chip operating in multi-harmonic oscillation mode to output a rectangular wave, using a resistor. R 1. R 2. R 3 and capacitors C 1. Control the period and duty cycle of the rectangular wave through a diode. D 1. D 2. Improve the flexibility of duty cycle adjustment.

4. The method for regulating the driving power supply of a gallium nitride device according to claim 1, characterized in that: The filter module includes resistors R 4. R 5. Inductance L 1. Capacitor C 3 and operational amplifier, wherein the inductor L One end of 1 is connected to a resistor R One end of 4, inductor L The other end of 1 is connected to the capacitor. C 3. Resistance R One end of 5 is connected to the non-inverting input of the operational amplifier, and the capacitor... C 3 and resistance R The other end of 5 is connected to ground, and the inverting input and output terminals of the operational amplifier are connected to the gate drive module. The resistor... R The other end of 4 is connected to pin 3 of the first-stage 555 chip.

5. The method for regulating the driving power supply of a gallium nitride device according to claim 1, characterized in that: The gate drive module includes a second-stage 555 timer chip and resistors. R 6. R 7. R 8. Diode D 3. D 4. Capacitor C 4. C 5, where resistance R 6 and R The common connection point of the 7-phase connection is connected to pin 7 of the second-stage 555 chip and the diode. D The anode of 3 is connected, and the resistance is... R The other end of resistor 6 is connected to pins 4 and 8 of the second-stage 555 chip and the output of the operational amplifier in the filter module. R The other end of 7 is connected to the diode. D The cathodes of 4 are connected, and the diode is... D 4 Anode and resistance R One end of the 8 is connected to pins 2 and 6 of the second-stage 555 chip, and the resistor is connected to the second-stage 555 chip. R The other end of 8 is connected to a diode. D The cathodes of 3 are connected, and the capacitor C 4 and C The common connection point of the 5-phase connection is connected to pin 1 of the second-stage 555 chip and grounded, capacitor C The other end of 4 is connected to the resistor. R The capacitor is connected to the sliding end of 8. C The other end of pin 5 is connected to pin 5 of the second-stage 555 chip, and the driver chip is connected to the second-stage 555 chip and the power module.

6. The gallium nitride device drive power supply regulation method according to claim 5, characterized in that: The gate drive module uses the DC power output from the filter module as its power supply. The second-stage 555 timer chip in this module generates the control signals required by the gate drive chip. Depending on the experimental requirements, the second-stage 555 timer chip is set to operate in multivibrator mode, monostable mode, or trigger mode. When the second-stage 555 timer chip operates in multivibrator mode, a resistor is used... R 6. R 7. R 8 and capacitors C 4. Control the period and duty cycle of the drive waveform to output a drive waveform that meets the design requirements. The gate drive chip is used to amplify the output current capability of the drive waveform to control the turn-on and turn-off of the subsequent gallium nitride transistor.

7. The method for regulating the driving power supply of a gallium nitride device according to claim 1, characterized in that: The power module includes resistors R 9 and the device under test, a gallium nitride transistor, and a resistor. R 9 is connected to the drain of the gallium nitride transistor, and the source and gate of the gallium nitride transistor are connected to the driver chip.

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