Driving system for enhanced GaN device
Through a multi-objective optimization model and an improved active gate drive strategy for the Miller clamp circuit, the crosstalk problem of GaN devices in bridge arm applications was solved, switching loss and EMI were optimized, and the reliability and integration of the drive circuit were improved.
Patent Information
- Application Number
- CN202510778341.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-10-03
AI Technical Summary
GaN power devices are susceptible to forward arm crosstalk in bridge arm applications, resulting in misdirection. The negative voltage spikes generated by reverse arm crosstalk may exceed the negative voltage withstand value of the device, leading to breakdown. At the same time, there is a trade-off between switching loss and EMI.
An active gate drive strategy based on a multi-objective optimization model is adopted, combined with an improved Miller clamp circuit. The optimal modulation drive signal is generated through timing control and a current mirror array to suppress bridge arm crosstalk. The Miller clamp circuit composed of PMOS, NMOS tubes and transistors suppresses crosstalk when the GaN device is turned off.
An effective compromise between switching loss and EMI is achieved, the reliability and integration of the drive circuit are improved, and the forward and reverse bridge arm crosstalk is suppressed without the need for additional control signals.
Smart Images
Figure CN120750150A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of circuit control, and in particular relates to a driving system for an enhancement-mode GaN device. Background Art
[0002] GaN power devices have smaller parasitic capacitance, which can achieve higher switching rates and reduce switching losses. However, a high conversion rate also increases EMI, and there is a trade-off between switching losses and EMI. Due to the low threshold voltage and small parasitic capacitance of GaN devices, they are more susceptible to positive bridge arm crosstalk in bridge arm applications, triggering false turn-on. For devices that use negative voltage shutdown, the negative voltage spike generated by the reverse bridge arm crosstalk may exceed the negative voltage withstand value of the device and cause device breakdown. Summary of the Invention
[0003] In order to solve the above problems, the present invention proposes a driving system for an enhancement-mode GaN device.
[0004] The technical solution of the present invention is: a driving system for an enhancement-mode GaN device comprises a local controller and an active gate driving module connected in sequence; The local controller is used to generate a modulated drive signal according to the bus voltage and load current collected by the sensor; The active gate driving module is used to generate an optimal modulated driving signal according to the modulated driving signal.
[0005] Furthermore, the local controller includes a multi-objective optimization model and a device switching behavior model; The multi-objective optimization model is used to assign weight values to various control parameters of the cost function according to the bus voltage and load current collected by the sensor, and obtain the optimal value of each control parameter; The device switching behavior model is used to generate a modulated drive signal based on the feedback value of the GaN device and the optimal values of various control parameters in the cost function.
[0006] Furthermore, the active gate drive module includes a timing control circuit, a current mirror array and a Miller clamp circuit; The timing control circuit is used to determine whether the GaN device enters or leaves the Miller clamp circuit according to the slope of the GaN device gate voltage, and to perform real-time timing control on the modulated drive signal; The current mirror array is used to generate an optimal modulation drive signal according to the drive strength information and timing information of the modulation drive signal; The Miller clamp circuit is used to suppress bridge arm crosstalk when the GaN device tube is turned off.
[0007] Furthermore, the Miller clamp circuit includes a PMOS tube, an NMOS tube, a transistor Q1, a transistor Q2, a power supply VCC, a resistor RG , resistor R B , capacitor C GD , capacitor C GS , capacitor C DS , GaN devices; The gate of the PMOS tube is connected to the gate of the NMOS tube; the source of the PMOS tube is connected to the positive electrode of the power supply VCC; the source of the NMOS tube is connected to the negative electrode of the power supply VCC, the resistor R B One end of the GaN device, the source of the capacitor C GS One end and capacitor C DS The drain of the PMOS tube is connected to the drain of the NMOS tube, the emitter of the transistor Q1, the collector of the transistor Q2 and the resistor R G The base of transistor Q1 is connected to the base of transistor Q2 and resistor R B The collector of transistor Q1 is connected to the emitter of transistor Q2 and the resistor R G The other end of the capacitor C GD One end of the capacitor C GS The other end of the GaN device is connected to the gate of the GaN device; the drain of the GaN device is connected to the capacitor C GD The other end and capacitor C DS to the other end of the
[0008] Furthermore, the cost function The expression is: ; Where, represents the first weight value, represents the second weight value, represents the first indicator parameter, Represents the second index parameter.
[0009] Furthermore, the specific method of assigning weight values to each control parameter of the cost function in the multi-objective optimization model is as follows: the bus voltage and load current are divided into several sub-intervals, and when the working state of the GaN component belongs to the end point of the sub-interval, the Determine the weight value ,in, Indicates that the corresponding parameter values are calculated according to the switch behavior model. Indicates the parameter value under minimum bus voltage and load current, Indicates the parameter value under maximum bus voltage and load current; When the working state of the GaN component belongs to the sub-interval, according to Determine a first weight value, where , , Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates that it falls within the subinterval The load current between Indicates that it falls within the subinterval The bus voltage between Indicates that the bus voltage is And the load current is The weight of express and The difference between Indicates that it falls at the endpoint of the subinterval The bus voltage at express and The difference between Indicates that it falls at the endpoint of the subinterval The load current at this time.
[0010] The present invention offers the following advantages: It proposes a model-based active gate drive strategy for GaN drivers, breaking away from the traditional fixed drive current model and enabling a better trade-off between switching losses and EMI. Furthermore, it proposes an improved Miller clamp circuit that suppresses forward and reverse bridge arm crosstalk without requiring additional control signals, significantly improving the reliability of the driver circuit and facilitating integration. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 Schematic diagram of the structure of the driving system for enhancement-mode GaN devices; Figure 2 This is the circuit diagram of the Miller clamp circuit. DETAILED DESCRIPTION
[0012] The embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0013] like Figure 1 As shown, the present invention provides a driving system for an enhancement-mode GaN device, comprising a local controller and an active gate driving module connected in sequence; The local controller is used to generate a modulated drive signal according to the bus voltage and load current collected by the sensor; The active gate driving module is used to generate an optimal modulated driving signal according to the modulated driving signal.
[0014] The present invention proposes a model-based control strategy and establishes a device switching behavior model to predict and control the device switching behavior, thereby achieving a trade-off between device switching loss and EMI. At the same time, the present invention improves the traditional Miller clamp circuit, using only two transistors and one resistor to achieve positive and negative crosstalk suppression without the need for additional control signals. The circuit structure is simple and easy to integrate. Using two transistors to suppress the forward and reverse bridge arm crosstalk respectively solves the problem that the traditional Miller clamp circuit has poor suppression effect on the reverse bridge arm crosstalk. Using resistor R B To protect the base of the transistor, when the GaN device is completely turned off, the Miller clamp circuit proposed in this patent automatically starts to work without the need for additional control signals. When the GaN device enters the turn-on transient state, the Miller clamp circuit is disconnected from the control loop without affecting the normal switching of the device.
[0015] In an embodiment of the present invention, the local controller includes a multi-objective optimization model and a device switching behavior model; The multi-objective optimization model is used to assign weight values to various control parameters of the cost function according to the bus voltage and load current collected by the sensor, and obtain the optimal value of each control parameter; The device switching behavior model is used to generate a modulated drive signal based on the feedback value of the GaN device and the optimal values of various control parameters in the cost function.
[0016] The device switching behavior model receives the feedback value of the device to modify the model and improve the adaptive ability.
[0017] In an embodiment of the present invention, the active gate drive module includes a timing control circuit, a current mirror array and a Miller clamp circuit; The timing control circuit is used to determine whether the GaN device enters or leaves the Miller clamp circuit according to the slope of the GaN device gate voltage, and to perform real-time timing control on the modulated drive signal; The current mirror array is used to generate an optimal modulation drive signal according to the drive strength information and timing information of the modulation drive signal; The Miller clamp circuit is used to suppress bridge arm crosstalk when the GaN device tube is turned off.
[0018] In the embodiment of the present invention, Figure 2As shown, the Miller clamp circuit includes a PMOS tube, an NMOS tube, a transistor Q1, a transistor Q2, a power supply VCC, and a resistor R G , resistor R B , capacitor C GD , capacitor C GS , capacitor C DS , GaN devices; The gate of the PMOS tube is connected to the gate of the NMOS tube; the source of the PMOS tube is connected to the positive electrode of the power supply VCC; the source of the NMOS tube is connected to the negative electrode of the power supply VCC, the resistor R B One end of the GaN device, the source of the capacitor C GS One end and capacitor C DS The drain of the PMOS tube is connected to the drain of the NMOS tube, the emitter of the transistor Q1, the collector of the transistor Q2 and the resistor R G The base of transistor Q1 is connected to the base of transistor Q2 and resistor R B The collector of transistor Q1 is connected to the emitter of transistor Q2 and the resistor R G The other end of the capacitor C GD One end of the capacitor C GS The other end of the GaN device is connected to the gate of the GaN device; the drain of the GaN device is connected to the capacitor C GD The other end and capacitor C DS to the other end of the
[0019] like Figure 2 As shown in the figure, the line close to transistor Q1 represents the forward Miller crosstalk current, and the line close to transistor Q2 represents the reverse Miller crosstalk current. After the GaN device is turned off, when forward crosstalk occurs, transistor Q1 is turned on and Q2 is turned off. The gate resistor R G When short-circuited, the crosstalk current flows through Q1, effectively suppressing the forward bridge arm crosstalk. When reverse crosstalk occurs, transistor Q2 turns on and Q1 turns off, and the gate resistor R G When short-circuited, the crosstalk current flows through Q2, effectively suppressing the reverse bridge arm crosstalk. The resistor RB is used to protect the base of the transistors Q1 and Q2. When the GaN device is turned on, the transistors Q1 and Q2 are both cut off, and the gate resistor R G The control loop is connected to suppress gate oscillation. At this time, the Miller clamp circuit is disconnected from the control loop without affecting the normal switching behavior.
[0020] In an embodiment of the present invention, the cost function The expression is: ; Where, represents the first weight value, represents the second weight value, represents the first indicator parameter, Represents the second index parameter.
[0021] In the embodiment of the present invention, the specific method of assigning weight values to the various control parameters of the cost function in the multi-objective optimization model is as follows: the bus voltage and the load current are divided into several sub-intervals, and when the working state of the GaN component belongs to the end point of the sub-interval, the weight value is assigned to the control parameter of the cost function by using Determine the weight value ,in, Indicates that the corresponding parameter values are calculated according to the switch behavior model. Indicates the parameter value under minimum bus voltage and load current, Indicates the parameter value under maximum bus voltage and load current; When the working state of the GaN component belongs to the sub-interval, according to Determine a first weight value, where , , Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates that it falls within the subinterval The load current between Indicates that it falls within the subinterval The bus voltage between Indicates that the bus voltage is And the load current is The weight of express and The difference between Indicates that it falls at the endpoint of the subinterval The bus voltage at express and The difference between Indicates that it falls at the endpoint of the subinterval The load current at this time. According to the same principle, the second weight value can be determined .
[0022] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.
Claims
1. A driving system for an enhancement-mode GaN device, characterized in that: including a local controller and an active gate drive module connected in sequence; The local controller is used to generate a modulated drive signal according to the bus voltage and load current collected by the sensor; The active gate driving module is used to generate an optimal modulated driving signal according to the modulated driving signal.
2. The driving system for an enhancement-mode GaN device according to claim 1, wherein: The local controller includes a multi-objective optimization model and a device switching behavior model; The multi-objective optimization model is used to assign weight values to various control parameters of the cost function according to the bus voltage and load current collected by the sensor, so as to obtain the optimal value of each control parameter; The device switching behavior model is used to generate a modulated driving signal according to the feedback value of the GaN device and the optimal value of each control parameter in the cost function.
3. The driving system for an enhancement-mode GaN device according to claim 1, wherein: The active gate drive module includes a timing control circuit, a current mirror array and a Miller clamp circuit; The timing control circuit is used to determine whether the GaN device enters or leaves the Miller clamp circuit according to the slope of the GaN device gate voltage, and to perform real-time timing control on the modulated drive signal; The current mirror array is used to generate an optimal modulated drive signal according to the drive strength information and timing information of the modulated drive signal; The Miller clamp circuit is used to suppress bridge arm crosstalk when the GaN device tube is turned off.
4. The driving system for an enhancement-mode GaN device according to claim 3, wherein: The Miller clamp circuit includes a PMOS tube, an NMOS tube, a transistor Q1, a transistor Q2, a power supply VCC, a resistor R G , resistor R B , capacitor C GD , capacitor C GS , capacitor C DS , GaN devices; The gate of the PMOS tube is connected to the gate of the NMOS tube; the source of the PMOS tube is connected to the positive electrode of the power supply VCC; the source of the NMOS tube is connected to the negative electrode of the power supply VCC, the resistor R B One end of the GaN device, the source of the capacitor C GS One end and capacitor C DS The drain of the PMOS tube is connected to the drain of the NMOS tube, the emitter of the transistor Q1, the collector of the transistor Q2 and the resistor R G The base of the transistor Q1 is connected to the base of the transistor Q2 and the resistor R B The collector of the transistor Q1 is connected to the emitter of the transistor Q2, the resistor R G The other end of the capacitor C GD One end of the capacitor C GS The other end is connected to the gate of the GaN device; the drain of the GaN device is connected to the capacitor C GD The other end and capacitor C DS to the other end of the 5. The driving system for an enhancement-mode GaN device according to claim 2, wherein: The cost function The expression is: ； Where, represents the first weight value, represents the second weight value, represents the first indicator parameter, Represents the second index parameter.
6. The driving system for an enhancement-mode GaN device according to claim 2, wherein: The specific method of assigning weight values to the various control parameters of the cost function in the multi-objective optimization model is as follows: dividing the bus voltage and load current into several sub-intervals, and using Determine the weight value ,in, Indicates that the corresponding parameter values are calculated according to the switch behavior model. Indicates the parameter value under minimum bus voltage and load current, Indicates the parameter value under maximum bus voltage and load current; When the working state of the GaN component belongs to the sub-interval, according to Determine a first weight value, where , , Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates the bus voltage is And the load current is The weight of Indicates that it falls within the subinterval The load current between Indicates that it falls within the subinterval The bus voltage between Indicates that the bus voltage is And the load current is The weight of express and The difference between Indicates that it falls at the endpoint of the subinterval The bus voltage at express and The difference between Indicates that it falls at the endpoint of the subinterval The load current at this time.