一种用于水听器电压检测的模拟前端电路

提出了一种用于水听器电压检测的模拟前端电路,包括低噪声低失调斩波运算放大器,跨导电容(gm-C)低通滤波器,增益放大器三部分主体电路;低噪声低失调斩波运算放大器用于提取水听器前端传感器输出的微弱电压信号;gm-C低通滤波器用于滤除电压信号频率外的高频噪声和高次谐波;最后经过增益放大器放大至后级模数转换器的输入电压范围,输出数字码流;芯片采用台积电(TSMC)0.18μm单层多晶硅六层金属(1P6M)CMOS工艺实现。测试结果表明,在电源电压1.8 V,输入信号25 kHz和200 kHz时钟频率下,斩波运放输入等效失调电压小于110μV;整体电路输出信号动态范围达到80 dB,功耗5.1 mW,满足水听器的检测要求。

Analog Front-end Circuit for the Voltage Detection of Hydrophone

For voltage detection of hydrophone an analog front-end was presented,including chopper-stabilized operational amplifier of low noise and low residual offset,gm-C low pass filter and voltage gain amplifier.The chopper-stabilized operational amplifier is used to detect the tiny voltage output by sensor in front of hydrophone.High frequency noise and harmonics are filtered by gm-C low pass filter.After amplified by the voltage gain amplifier,the signal is output to ADC,which outputs the digital code.The circuit is implemented in TSMC 0.18 μm 1P6M CMOS process.The measurement results show that in 1.8 V power supply,25 kHz input frequency and 200 kHz clock frequency,the input residual offset of chopper-stabilized operational amplifier is 110 μV,the dynamic range of circuit is 80 dB with 5.1 mW power consumption,meets the requirement of hydrophone detection.