用于关断耗尽型GaN器件的Buck-Boost负压电路

A Buck-Boost Negative Voltage Circuit for Turning-Off Depletion-Mode GaN Devices

设计了一种Buck-Boost负压关断电平产生电路。通过引入动态调整关断时间的计时模块、分段电流限模块和纹波高速检测模块,实现了在耗尽型GaN器件快速开关时稳定栅极负压的供给,有效消除了耗尽型GaN器件在高压应用时密勒误开启现象的发生。电路基于0.35μm BCD工艺进行设计与仿真验证。结果表明,该电路在宽输入范围内稳定输出-14 V的负压,在20~130 mA恒定负载电流下工作效率达80~87%,在0.5~1 MHz的工作频率下GaN器件栅极开关切换期间输出电压依然稳定。该电路满足高压应用需求。

A buck-boost negative shutdown voltage generation circuit was designed.By introducing a dynamically adjustable off-time timing module,a segmented current-limit module and a ripple based high speed detection module,a stable negative gate voltage supply was achieved during the fast switching of depleted GaN devices,which effectively eliminated the occurrence of Miller open when depletion-mode GaN devices were used in high-voltage applications.The circuit was designed and simulated in a 0.35μm BCD process.The results showed that the circuit could output stably a negative voltage of-14 V in a wide input range,the operating efficiency could reach 80%~87%under 20~130 mA constant load current.The output voltage of GaN device kept stable during gate switches switching at 0.5~1 MHz operating frequency.This circuit met the needs of high voltage applications.