高压DC-DC控制器高效功率管驱动电路研究

Study on high efficiency power transistor drive circuit of high voltage buck DC-DC controller

针对高压降压DC-DC(直流转直流转换器)输入电压范围宽的特点,设计了驱动电路通过钳位电路设定高压的驱动电压,同时通过源极跟随提供驱动功率管开启的驱动电流.电路集成于一款40 V 0.18μm BCD(双极型晶体管、互补金属氧化物半导体和双扩散金属氧化物半导体)工艺的高压降压DC-DC控制器芯片中,测试结果表明:在200 kHz开关频率下空载功耗为4 mA;驱动功率管开启电压最高为14 V,当输入电压小于14 V时能够提供接近输入电压的驱动压差;PMOS(P型金属氧化物半导体)功率管栅极电压驱动速率在40 V/μs以上,NMOS(N型金属氧化物半导体)功率管栅极电压驱动速率在60 V/μs以上.驱动电路具有高驱动速度和高驱动电压差,以降低开关损耗及导通损耗.

For the wide input voltage range of high-voltage step-down DC-DC,the high-voltage drive voltage was produced by the clamp circuit of the drive circuit proposed,and the on current of power transistor was provided by the source follower. The proposed circuit was integrated into a 40 V 0.18 μm BCD(bipolar,complementary and double-diffused metal oxide semiconductor)process high voltage step-down DC-DC controller. The test results show that the no-load power consumption is 4 mA at 200 kHz switch frequency.The maximum on voltage power transistor is 14 V.When the input voltage is less than 14 V,the drive voltage is close to the input voltage to maximize the drive voltage. The gate voltage switch rate of PMOS and NMOS power transistor are above 40 V/μs and 60 V/μs,respectively. The drive circuit has fast drive speed and high drive voltage to reduce switch loss and conduction loss.