A 4.7.MU.A Quiescent Current, 450mA CMOS Low-Dropout Regulator with Fast Transient Response

This paper presents a new low-dropout (LDO) regulator with low-quiescent, high-drive and fast-transient performance. This is based on a new composite power transistor composed of a shunt feedback class-AB embedded gain stage and the application of dynamic-biasing schemes to both the error amplifier as well as the composite power transistor. The proposed LDO regulator has been simulated and validated using BSIM3 models and GLOBALFOUNDRIES 0.18-µm CMOS process. The simulation results have shown that the LDO regulator consumes 4.7µA quiescent current at no load, regulating the output at 1V from a minimum 1.2V supply. It is able to deliver up to 450mA load current with a dropout of 200mV. It can be stabilized using a 4.7µF output capacitor with a 0.1Ω ESR resistor. The maximum transient output voltage is 64.6mV on the basis of a load step change of 450mA/10ns under typical condition. The full load transient response is less than 350ns.