一种用于高压PMOSFET驱动器的电压跟随电路

通常PMOSFET栅源电压为-20~20 V,而用于GaN功率放大器的高压PMOSFET驱动器,其工作电压为28~50 V,因此需要一种新型电路结构来保证PMOSFET栅源电压工作在额定范围。设计了一种新型电压跟随电路,采用新型多环路负反馈结构,核心电路主要为电压基准单元、减法器单元、误差放大器单元和采样单元,可产生稳定的跟随电压。该电路具有宽电源电压范围、高输出稳定性以及低温度漂移等特性。基于0.5μm BCD工艺对电路进行流片,测试结果表明,采用该电路的驱动器芯片,其电源电压为15~50 V,输出电压变化量约为0.6 V,在-55~125℃温度范围内,电压漂移量约为0.12 V,满足大多数PMOSFET栅源电压的应用要求。

A Voltage Following Circuit for the High Voltage PMOSFET Driver

The gate-source voltage of most PMOSFETs is from-20 V to 20 V,while the high vol-tage PMOSFET drivers for GaN power amplifier operate at 28-50 V,so a novel circuit structure is needed to ensure the gate-source voltage operating in the rated voltage range.A novel voltage following circuit with the multi-loop negative feedback structure was designed,and the core circuit mainly consisted of voltage reference unit,subtractor unit,error amplifier unit and sampling unit.The designed circuit can generate stable following voltages,and has a wide power supply voltage range,high output stability and low temperature drift.The circuit was taped out based on 0.5μm BCD process.The test results show that the driver chip using the designed circuit operates properly at the power supply voltages of 15-50 V,the output voltage variation is about 0.6 V and the voltage drift is about 0.12 V in the temperature range of-55-125℃,which meets the application requirments of gate-source voltage of most PMOSFETs.