Publisher : The Korean Institute of Electrical and Electronic Material Engineers
DOI : 10.4313/TEEM.2016.17.3.172
Title & Authors
Effect of R-C Compensation on Switching Regulation of CMOS Low Dropout Regulator Choi, Ikguen; Jeong, Hyeim; Yu, Junho; Kim, Namsoo;
Miller feedback compensation is introduced in a low dropout regulator (LDO) in order to obtain a capacitor-free regulator and improve the fast transient response. The conventional LDO has a limited bandwidth because of the large-size output capacitor and parasitic gate capacitance in the power MOSFET. In order to obtain a stable frequency response without the output capacitor, LDO is designed with resistor-capacitor (R-C) compensation and this is achieved with a connection between the gain-stage and the power MOS. An R-C compensator is suggested to provide a pole and zero to improve the stability. The proposed LDO is designed with the 0.35 μm CMOS process. Simulation testing shows that the phase margin in the Bode plot indicates a stable response, which is over 100o. In the load regulation, the transient time is within 55 μs when the load current changes from 0.1 to 1 mA.