脉冲调制模式GaN功放电压过冲的机理研究

Mechanism Research of Suppressing The Power Amplifier Switching off Voltage Overshoot

脉冲调制GaN功率放大器已大量应用于雷达及通信系统,随着技术的发展,脉冲功放的开关速度和功率量级不断提高。由于线路和器件内部分布电感的存在,关断时漏极电流的快速变化会感应产生较大的电压尖峰,严重时会引起功放漏极击穿。文中以大功率GaN脉冲功放管为例,研究了电压尖峰的产生机理。经理论分析推算、仿真设计、实测验证,研究出了抑制电压过冲的有效措施。

Pulse modulated GaN power amplifier has been widely used in radar and RF communication systems.With the development of semiconductor technology,the switching speed and power level of pulse mode amplifiers have been continuously improved.Due to the existence of distributed inductance in the circuits and devices,there is a high voltage overshoot when the amplifier shuts down with drain current changes quickly.The voltage overshoot is a huge hazard because the peak voltage is too high to damage the device.In this paper,we use a high-power GaN pulse mode amplifier to study the principle of voltage overshoot and its impact on the device.To improve the device reliability,we design a circuit that can effectively suppress voltage overshoot through theoretical calculation and software simulation.It is measured in the experiment that the circuit can limit the voltage overshoot.