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

Sau Siong CHONG
Pak Kwong CHAN

IEICE TRANSACTIONS on Electronics   Vol.E94-C    No.8    pp.1271-1281
Publication Date: 2011/08/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.1271
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
power management IC,  composite transistor,  dynamic-biasing,  LDO regulator,  low quiescent LDO,  high drive LDO,  fast transient LDO,  

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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 4.7 µA quiescent current at no load, regulating the output at 1 V from a minimum 1.2 V supply. It is able to deliver up to 450 mA load current with a dropout of 200 mV. It can be stabilized using a 4.7 µF output capacitor with a 0.1 Ω ESR resistor. The maximum transient output voltage is 64.6 mV on the basis of a load step change of 450 mA/10 ns under typical condition. The full load transient response is less than 350 ns.