← 返回 JSSC 论文列表JSSC 2023第6期Digital Circuits0.18μm CMOSNeural Network Accelerator
A0 . 5 - m/√ Hz Dry-Electrode Bioimpedance Interface With Current Mismatch Cancellation and Input Impedance of 100 M at 50 kHz Qinjing Pan
一种用于干电极生物阻抗监测的高输入阻抗、低噪声传感器接口IC
100 MΩ输入阻抗@50 kHz, 0.5-mV/√Hz灵敏度@1 Hz, 106 dB SNR
生物阻抗干电极高输入阻抗低噪声心电监测
▸创新点1：偏置控制环路（BCL）技术，通过动态调整输入偏置电压消除激励电流失配，显著降低高阻抗输入端的电压波动，提升系统稳定性（电路创新）。该技术使输入阻抗达到100 MΩ@50 kHz，支持干电极应用。
▸创新点2：静音斩波电流反馈仪表放大器（QC-CFIA）设计，采用斩波调制与电流反馈结构，抑制输入信号相关噪声（1/f噪声等），实现0.5 μV/√Hz@1 Hz的超低噪声性能（电路创新）。
▸创新点3：全预充电（FPC）技术，通过预充电周期完全抵消输入寄生电容效应，将输入阻抗提升一个数量级（方法创新），解决了小尺寸干电极（0.45 cm²）的信号衰减问题。
▸创新点4：系统级低功耗优化，通过分模块动态功耗管理（放大器15.8 μW，激励发生器14.4-128.4 μW），在0.18 μm CMOS工艺下实现0.4 mm²芯片面积与106 dB SNR（系统创新）。
Abstract
This article describes a high-input-impedance, low- noise bioimpedance (BioZ) sensor interface IC for small-area dry-electrode cardio-respiratory signals monitoring. To facilitate high-precision BioZ sensing with high-impedance dry electrodes, the IC utilizes three key techniques as follows: 1) a bias control loop (BCL) to eliminate the excitation current mismatch, reduc- ing the voltage fluctuation on high-impedance input; 2) a quiet- chopping current feedback instrumentation amplifier (QC-CFIA) to mitigate the input-signal-dependent noise; and 3) a full pre- charge (FPC) technique to cancel the input parasitic capacitance for impedance boosting. Manufactured in a 0.18- μmC M O S process, the BioZ prototype IC occupies an area of 0.4 mm 2 while consuming 15.8- and 14.4–128.4- μW current, respectively, from the amplifier and the excitation current generator (CG). With these proposed techniques, this IC achieves a high input impedance of 100 M at 50 kHz, 0.5-m /√Hz sensitivity at 1 Hz, and a 106-dB signal-to-noise ratio (SNR). A gel-free respiration and impedance cardiography (ICG) recording has been successfully demonstrated on the human body with four 0.45-cm 2 dry electrodes.