JSSC 2009第12期Digital CircuitsNeural Network Accelerator

A Chopper Current-Feedback Instrumentation Ampliﬁer With a 1 mHz 4961102Noise Co

提出一种斩波电流反馈仪表放大器，用于高精度热敏电阻桥接口，具有极低噪声和高共模抑制比。

15nV/√Hz输入参考噪声, 120dB CMRR, 5μV最大输入偏移, 230μA@5V

斩波放大器电流反馈仪表放大器低噪声纹波抑制

▸采用三级电流反馈拓扑与嵌套米勒补偿实现高CMRR和直流增益

▸通过斩波输入和中间级实现1mHz/49噪声拐点

▸连续时间交流耦合纹波抑制环路减少斩波纹波60dB以上

Abstract

This paper presents a chopper instrumentation ampliﬁer for interfacing precision thermistor bridges. For high CMRR and DC gain, the ampliﬁer employs a three-stage cur- rent-feedback topology with nested-Miller compensation. By chopping both the input and intermediate stages of the ampliﬁer, a 1 mHz /49 noise corner was achieved at an input-referred noise power spectral density (PSD) of 15 nV/ Hz. To reduce chopper ripple, the ampliﬁer employs a continuous-time AC-coupled ripple reduction loop.