Low Supply Voltage, Low Quiescent Current, High PSRR Reference Current And Reference Voltage Generation Circuits for Low Power Applications

Abstract

This thesis focuses on designing voltage and current reference circuits keeping high PSRR, low IQ and low supply voltage operation in mind. These circuits are one of the most critical blocks of a power management IC as they bias the LDOs and oscillators in any system. High PSRR makes the reference robust to noise at the supply. Low IQ enables the reference to operate in an energy harvesting system. Low supply voltage operation enables the reference to act as a voltage reference for crude power-on-reset comparator. Negative feedback arrangements are put to use to get good PSRR, subthreshold operation of MOSFETs is chosen to generate low bias current and low supply voltage. Although CMOS voltage and current references have great area and IQ specifications but they struggle when it comes to having good accuracy. Therefore, a hybrid voltage reference consisting of BJTs and MOSFETs is also proposed to improve the accuracy of the published voltage reference. Furthermore, having 2 different circuits for generating a reference voltage and a reference current can result in area overhead. Therefore, a 2-in-1 voltage + current reference circuit is also presented in this thesis.