An offset-insensitive switched-capacitor bandgap reference with continuous output

Abstract

An improved switched-capacitor bandgap reference with a continuous output voltage of 1.26 V has been implemented with Chartered 0.35-μm 5-V CMOS process. The output offset voltage, induced by non-ideal characteristics of operational amplifier and bias current generator, is suppressed by the proposed sample-and-hold circuit and self-bias technique. Experimental results show that the proposed circuit operates properly under a supply voltage varying from 3 to 5 V. The measured temperature coefficient is 112 ppm/°C and the power supply rejection ratio of output voltage without any filtering capacitor is −40 dB and −33 dB at 100 Hz and 10 MHz, respectively.

All switched-capacitor realized piezoresistive pressure sensor interface chip for automotive TPMS

“…During the sample phase (F1), capacitor C1 sample the difference emitter-base voltage of the two BJTs while C3 acts as feedback capacitor, which causes the op-amp output to change only by the op-amp input offset voltage. This is a much smaller value than the structure [4]. Since the output dynamic range is reduced, the requirement of slew-rate of op-amp is greatly relaxed and attractive to low power design.…”

“…Compared with conventional SC bandgap voltage reference [4], the proposed circuit adopts CDS technique to reduce op-amp offset voltage and finite gain effects. As shown in Fig.…”

A Wireless Sensor Node Supporting Various Powers Supply and Communication Methods

“…The bias cell operates according to the principle of a switch capacitor band gap reference. This principle is first published in (Peng et al, 2009).…”