Current controlled capacitor less low dropout voltage regulator for fast transient response

Abstract

This paper discusses and address a transistor based new current control low dropout voltage regulator (LDO) offering a high gain and large bandwidth without using complex compensation and large output capacitor. The conventional error amplifier based LDO which is using voltage feedback loop suffers from an inherent poor load transient response. The poor load transient associated with error amplifier results because of limited DC open-loop gain and limited closed loop bandwidth. The frequency response of error amplifier based LDO is highly sensitive to load current. Current controlled transistor based LDO has been designed for fast dynamic response with low output capacitor in the range of 1 to 10 uF. Experimental results show circuit has small output voltage variations of less than 10 mV for load current variation in the range of 0–3A without any overshoot or undershoot. This circuit is also simulated in PSpice and results are compared with Hardware LDO.