A capacitor-free CMOS low-noise, low-dropout regulator for capacitive micro-machined accelerometer application

摘要

A capacitor-free CMOS low-noise,low-dropout (LDO) regulator for Micro-accelerometer is presented. Noise performance of the regulator is studied from a theoretical point of view and a chopper stabilized error amplifier is designed to minimize output noise. By adopting pole-zero frequency compensation technique, the proposed LDO regulator, which is independent of an off-chip capacitor, provides high closed-loop stability when the load current is switched by micro-accelerometer. The simulation results show that the input referred noise of the regulator is 21.821nv/Hz1/2 ranging from 1Hz to 10kHz and integrated noise is 2.18μV with chopping frequencies high enough. PSR is 55dB at 10kHz. The line regulation is 3.5mV/V and the load regulation is 0.33mV/mA when the load current changes from 0 to 30 mA.