一种基于自适应时钟和波纹减少环路的高精度电流反馈仪表放大器

A high precision current-feedback instrumentation amplifier based on adaptive CLK and ripple reduction loop

电流反馈仪表放大器芯片因其高精度、高共模抑制比等优势,广泛应用于微弱信号检测。传统CFIA利用斩波技术降低1/f噪声和失调电压以提升放大器精度,但额外引入斩波波纹会显著限制其精度提升。为此,本文提出一种基于自适应时钟和波纹减小环路的新型电流反馈仪表放大器ARCFIA,该放大器针对传统斩波放大器波纹,采用波纹减少环路RRL对其抑制,并借助自适应时钟ACLK,将斩波开关的输入参考噪声谱密度降低。实验结果表明,ARCFIA实现了低于1.4μV的低失调电压和17.2 nV/√Hz的输入参考噪声,同时波纹被减少到ARCFIA噪声基底以下,通过减小失调、噪声和波纹,实现了精度的进一步提升。此外,ARCFIA还具有一定潜力应用于复杂环境下的高精度测量系统。

The current-feedback instrumentation amplifier chip is extensively employed in weak signal detection due to its high precision and high common-mode rejection ratio.Conventional CFIA utilizes chopping techniques to reduce 1/f noise and offset voltage,enhancing the amplifier′s precision.However,the resultant ripple significantly limits the accuracy improvement.Addressing this,an innovative adaptive CLK ripple reduction loop CFIA ARCFIA is proposed.It employs a ripple reduction loop RRL to reduce the ripple in conventional chopping amplifiers.In addition,with the aid of an Adaptive CLK ACLK,it reduces the power spectral density of the inputreferred noise in chopping switch.Experimental results show that ARCFIA achieves a low offset voltage below 1.4μV and an inputreferred noise of 17.2 nV/√Hz,while the ripple is reduced to a level below the ARCFIA′s input-referred noise.This reduction in offset,noise,and ripple leads to improved accuracy.Furthermore,ARCFIA shows potential for application in high-precision measurement systems within complex environments.