适合容性负载的高压大功率放大器

设计了一种适合压电陶瓷等容性负载的双极性可调高压大功率线性放大器,它由简单低廉的低压运算放大器、基于功率场效应管(MOSFET)的功率放大级组成主回路,通过电压负反馈构成闭环控制。对电路中各环节的特性进行了分析,并讨论了放大器的性能。该高压放大器在驱动等效电容为60nF的压电陶瓷时,单端到地输出电压为一600～ 600V,电压增益42dB,大信号带宽800Hz,小信号带宽7kHz,充放电电流可达200mA,静态电流可达1．4mA。实验与分析表明,高压直流放大器采用功率场效应管和电压闭环控制后,可拓展放大器通频带,提高放大器输出能力和长时间稳定性。

A High-voltage High-power Amplifier for Capacitive Loads

An adjustable double-polarity high-voltage high-power linear amplifier driver for piezoelectric ceramic class capacitive loads is designed. Using a simple universal operation amplifier and a power amplifier based on power MOSFETs develops a DC high voltage amplifier. Voltage feedback is employed to stabilize the high voltage outputs.The amplifier characteristics and amplifier performance are analyzed to provide a maximum single-ended output voltage of 1.2 kV(peak to peak), a voltage gain of 42 dB, a large-signal bandwidth greater than 800 Hz, a small-signal bandwidth greater than 7 kHz, a charge/discharge current of order 200 mA, and a maximum power consumption of less than 3 W with a piezoelectric ceramic load (equivalent capacitance of 60 nF).The experimental and analytical results demonstrate that wide bandwidth, high voltage output and long-time stability can be achieved with power MOSFETs and a closed-loop scheme.