基于OPA454的新型高压级联放大器优化设计

Optimized Design of New High Voltage Cascaded Amplifier Based on OPA454

为获取频率可调的高线性度电压信号,提出基于OPA454的高压级联线性放大器的优化设计方案。首先,设计高压级联放大器的主电路、隔离电路和级联放大电路;然后,分析此线性放大器的负反馈特性和容性负载特性,保证输出电压信号的高线性度和带容性负载能力;最后,搭建两级级联放大电路模型,时域下测试输入电压频率分别为0.001 Hz、1.0 Hz、1.0 kHz、10 kHz时放大器的输入输出波形,在频域下对比一级电压放大电路和两级电压放大电路的频率响应曲线。结果表明:设计的新型线性放大器输出的电压波形可对输入电压线性放大40 n倍,并达到较高的线性度和低波形失真率,满足可调频率下电压准确放大的要求。

To acquire high linearity voltage signal with adjustable frequency,this paper proposes an optimal design scheme of high voltage cascaded linear amplifier based on OPA454.It firstly designs the main circuit,the isolation circuit and the cascade amplifier circuit,and then analyzes the negative feedback characteristics and capacitive load characteristics of the linear amplifier to ensure high linearity and capacitive load capability of the output voltage signal.Finally,by establishing a two-stage cascade amplifier circuit model,it tests input and output waveforms of the amplifier in time domain at 0.001 Hz,1.0 Hz,1.0 kHz and 10 kHz,and compares frequency response curves of the first-stage voltage amplifier circuit and the two-stage voltage amplifier circuit in the frequency domain.The results show that the output voltage waveform of the new linear amplifier can be linearly amplified by 40 n times of the input voltage,which achieves high linearity and low waveform deviation factor.And the output voltage waveform can meet the requirement of accurate voltage amplification under adjustable frequency.