A push-pulled capacitor-less FVF LDO with active feed-forward compensator

Abstract

ABSTRACT An output capacitor-less flipped voltage follower (FVF) low dropout regulator (LDO) with an active feed-forward compensator is presented. A simple compensator which consists of a miller capacitance and an NMOS pass transistor is used to stabilise the LDO. The miller capacitance places the dominant pole at the gate of the power transistor and provides better transient and small-signal responses than the case when the dominant pole places at the drain of the control transistor. The pass transistor placed between the drain of the control transistor and the output node and provides an additional phase lead by shifting all the significant zeros from RHP to LHP. This compensator extends the unity gain frequency and provides the required phase and gain margin to make the LDO stable. This LDO can drive the load current range 0–50 mA with stable regulated output voltage ranges from 1.2 to 1.6 V. The quiescent current of the proposed LDO is at a maximum load current of 50 mA.