CMOS fast-settling time low pass filter associated with voltage reference and current limiter for low dropout regulator

Abstract

In this work, a fast turn-on settling low dropout regulator (LDO) with current limiter is presented. Dynamically operating the proposed current limiter using a decent current comparator protects the IC from any damage when an overload condition occurs or the output of the regulator is shorted. A novel low pass filter associated with voltage reference circuit, which provides highly filtered reference voltage and fast settling time, is implemented to minimize output noise due to voltage reference noise. The LDO with proposed low pass filter and current limiter has been implemented in a 0.6μm n-well CMOS process. The LDO dissipates 65 μA quiescent current at 150mA full load condition and its output noise is 407.8 nV/√Hz at 100Hz. Turnon settling time of the LDO is 45μsec and threshold current of the current limiter is set to 230mA of output load current. © IEICE 2009.