A Wide Current Range and Fast Transient Flipped Voltage Follower Based Low Dropout Regulator

Flipped voltage follower (FVF) based low dropout regulators (LDOs) have been developed rapidly in recent years due to their low circuit complexity, fast transient response and high power supply rejection (PSR). The FVF can be used to replicate the reference voltage ($\mathrm{V}_{\text {REF }}$) as the output voltage (Vout) of the LDO and then conduct feedback regulation [1], or implement a fully integrated fast response loop [2]. The conventional FVF loop encounters stability challenges under heavy load conditions when employing dominant pole compensation with a large output capacitance. The load-dependent dominant pole ($\mathrm{p}_{\mathrm{o}}$) at the output of the LDO causes an increase in unity-gain frequency (UGF) when the load current increases, and thus the maximum load current is limited by the poles at the output of the gain stage and at the gate of the power transistor.