A Current-Feedback Instrumentation Amplifier with a Gain Error Reduction Loop and 0.06% Untrimmed Gain Error

📋 论文概要

该论文提出了一种采用连续时间增益误差降低环路的斩波电流反馈仪表放大器，解决了传统CFIA因跨导器失配导致增益精度有限的问题，实现了0.06%的未修调增益误差。

💡 主要创新点

• 提出连续时间增益误差降低环路，通过反馈环路自动校正跨导器失配引起的增益误差，无需修调。
• 结合斩波技术降低低频噪声和失调，同时保持高增益精度和低功耗。

🏷 关键词

📄 原文摘要

Current-feedback instrumentation amplifiers (CFIAs) have significant advantages over the classic three-opamp topology: better power efficiency [1, 2], higher CMRR and rail-sensing capability [4]. Their main disadvantage, however, is their limited gain accuracy, which is determined by the mismatch of two transconductors. Using resistor-degenerated differential pairs, 0.1% gain error and improved linearity have been achieved [3, 4]. However, this incurs either increased noise or increased power. This paper describes a chopper CFIA that employs a continuous-time (CT) gain error reduction loop (GERL) without incurring a noise penalty. Without trimming, it achieves a gain error of less than 0.06% and a maximum gain drift of 6ppm/°C in a power efficient manner (NEF=11.2). A block diagram of the CFIA is shown in Fig. 13.5.1. Input and feedback transconductors Gm3 and Gm4 convert the input and feedback voltages into currents, which are then applied to the virtual ground established by a 2-stag

👥 作者与机构

Rong Wu, Johan H. Huijsing, Kofi A.A. Makinwa

Delft University of Technology, Delft, The Netherlands