GaN Transistor Driving Circuit for False Turn-On Prevention
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Solution Overview
Problem
GaN transistors experience false turn-on due to high-frequency oscillations caused by parasitic inductance and capacitance, leading to device burnout, which existing driving methods fail to reliably prevent.
Innovation Solution
A driving control circuit and method that includes an ADriver pin and an electronic switch, where the ADriver pin is used to control the gate-source voltage of the GaN transistor to zero, preventing false turn-on by managing dead times and oscillations between the leakage inductance of the transformer and parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching frequency is increased to improve power density and conversion efficiency, then the power converter achieves higher performance, but high-frequency oscillation caused by parasitic inductance becomes more severe
Solution Approach 1:
The patent applies preliminary anti-action by introducing a clamp circuit that actively counteracts high-frequency oscillations before they can cause harmful effects. The clamp circuit detects oscillation conditions and applies compensating voltage to suppress the oscillation, preventing false turn-on and device burnout while allowing high switching frequencies to be used
2Reliability
If the gate-source withstand voltage is reduced to 7V to enable GaN transistor operation, then the transistor achieves lower on-resistance and better performance, but the transistor becomes more susceptible to voltage spikes from oscillation
Solution Approach 1:
The patent applies beforehand cushioning by implementing a clamp circuit that prepares protective measures in advance. The circuit monitors voltage conditions and activates protection mechanisms before voltage spikes can exceed the 7V gate-source withstand voltage, cushioning the GaN transistor against harmful voltage excursions while maintaining its low-voltage operational advantages
3Device complexity
If simple voltage driving is used to control the GaN transistor, then the driving circuit is simplified, but false turn-on due to oscillation cannot be prevented
Solution Approach 1:
The patent introduces an intermediary element - the clamp circuit with its detection and control components - that mediates between the simple voltage driving signal and the GaN transistor. This intermediary monitors oscillation conditions and inserts protective actions into the driving signal path, preventing false turn-on while maintaining relative simplicity of the overall driving architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents false turn-on and ensures reliable operation of GaN transistors by stabilizing the gate-source voltage, thereby reducing the risk of device burnout and adapting to various frequency and duty cycle changes.
Implementation Method 1
after the GaN transistor is turned off, the drain-source parasitic capacitance of the GaN transistor produces the high-frequency oscillation with the leakage inductance of the flyback high-frequency transformer
Implementation Method 2
the parasitic inductance of the GaN transistor package and the parasitic inductance of the printed circuit board (PCB) trace
Data Source
AI summary
The present disclosure relates to a driving control circuit, method and device for a gallium nitride (GaN) transistor, and a medium. An ADriver pin and an electronic switch are added to an existing flyback power supply circuit. The electronic switch includes a first terminal connected to the ADriver pin, a second terminal connected between a driving resistor and a GaN transistor, and a third terminal connected between a current detection resistor and a current sense pin. By improving the driving control circuit and the driving control method for the GaN transistor, the present disclosure can effectively prevent the false turn-on problem due to high-frequency oscillation between the leakage inductance of the transformer and the parasitic capacitance after the GaN transistor is turned off, and drives the GaN transistor more reliably.