Micro EEG/ECG signal’s chopper-stabilization amplifying chip for novel dry-contact electrode

Abstract

Facing the body's EEG (electroencephalograph, 0.5-100 Hz, 5-100 V) and ECG's (electrocardiogram, < 100 Hz, 0.01-5 mV) micro signal detection requirement, this paper develops a pervasive application micro signal detection ASIC chip with the chopping modulation/demodulation method. The chopper-stabilization circuit with the RRL (ripple reduction loop) circuit is to suppress the ripple voltage, which locates at the single-stage amplifier's outputting terminal. The single-stage chopping core's noise has been suppressed too, and it is beneficial for suppressing noises of post-circuit. The chopping core circuit uses the PFB (positive feedback loop) to increase the inputting resistance, and the NFB (negative feedback loop) to stabilize the 40 dB intermediate frequency gain. The cascaded switch-capacitor sample/hold circuit has been used for deleting spike noises caused by non-ideal MOS switches, and the VGA/BPF (voltage gain amplifier/band pass filter) circuit is used to tune the chopper system's gain/bandwidth digitally. Assisted with the designed novel dry-electrode, the real test result of the chopping amplifying circuit gives some critical parameters: 8.1 W/channel, 0.8 Vrms (@band-width D 100 Hz) , 4216-11220 times digitally tuning gain range, etc. The data capture system uses the NI CO's data capturing DAQmx interface, and the captured micro EEG/ECG's waves are real-time displayed with the PC-Labview. The proposed chopper system is a unified EEG/ECG signal's detection instrument and has a critical real application value.

Design of a urinator system with sensor front-end readout and drug delivery actuator based on TSMC 0.18 μm technology

“…The chopper stabilization principle is shown in Fig. 3 (Sun et al 2017). Upon down modulation, all the noise and offset signals are at the higher frequency end and can readily be low pass filtered.…”

“…Fig. Chopper stabilization technique to reduce circuit noise and offset for low noise amplifier implementation(Sun 2017) …”