This paper presents an ultra-low-power current-mode ECG instrumentation amplifier, which is designed based on the current balancing technique and fabricated in TSMC 0.35 μm CMOS process. The instrumentation amplifier, which is presented here has three features. First, the instrumentation amplifier is a full-CMOS implementation of current-balancing technique applied for ECG signal conditioning. Second, the instrumentation amplifier is of ultra-low-power due to a power-oriented design methodology, which makes its power consumption very low compared to the earlier reported works for ECG recording applications. Third, integrated programmable bandpass filtering is implemented in the amplifier itself, which provides a compact solution for analog ECG signal conditioning. Measurement results show that the amplifier only draws 9 μA current from a 3.3 V lithium-ion battery, while CMRR of 100 dB and input voltage dynamic range of ± 6 mV are achieved. By considering trade-offs between input noise voltage and power, noise performance was compromised with power and area for ultra-low-power ECG signal conditioning applications. Measurement results show [Formula: see text] input referred noise voltage with a flicker noise corner frequency of 15 Hz at 9 μA dc current and small area, which is appropriate for the desired application. Measurement results meet the recommended specifications for signal conditioning of portable ECG monitoring devices. Design methodology, fabrication considerations, measurement setup, and experimental results are also explained in this paper.
Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications
