Title :
A 9.4-bit, 28.8-mV range inverter based readout circuit for implantable pressure bridge piezo-resistive sensor
Author :
Trung Nguyen Thanh ; Hafliger, Philipp
Author_Institution :
Dept. of Inf., Univ. of Oslo, Oslo, Norway
Abstract :
This paper presents an energy efficient inverter based readout circuit for implantable pressure bridge piezo-resistive sensor which can achieve 9 bit resolution with 28.8-mV input voltage range. Only one bridge branch is utilized with interchanging supply voltage to achieve net differential input voltage range, hence reducing the power consumption by a half. A gain compensated technique is applied for inverter based switched capacitor amplifier to achieve both power efficiency and high resolution. A two-step auto calibration is applied to eliminate the offset from non-ideal effects of the switched-capacitor amplifier (SC-amp) and comparator delay. The readout system is implemented and simulated in TSMC 90 nm CMOS technology. With supply voltage of 1.2 V, simulation results show that the circuit can achieve 9.4 bit resolution while consuming only 35 μW during 320 μs conversion time. The digital output code has little sensitivity to temperature variation.
Keywords :
CMOS integrated circuits; amplifiers; biomedical electronics; biomedical measurement; comparators (circuits); invertors; piezoresistive devices; pressure sensors; prosthetics; readout electronics; switched capacitor networks; CMOS technology; comparator delay; energy efficient inverter; gain compensated technique; implantable pressure bridge piezoresistive sensor; power 35 muW; readout circuit; size 90 nm; switched capacitor amplifier; voltage 1.2 V; voltage 28.8 mV; Bridge circuits; CMOS integrated circuits; Clocks; Gain; Inverters; Resistance; Temperature sensors;
Conference_Titel :
Circuits and Systems (ISCAS), 2014 IEEE International Symposium on
Conference_Location :
Melbourne VIC
Print_ISBN :
978-1-4799-3431-7
DOI :
10.1109/ISCAS.2014.6865650
