US Patent 10281943 Low dropout regulator with a controlled startup

A low dropout voltage regulator incorporates an N-channel MOS pass transistor, a main error amplifier, a first buffer circuit, an auxiliary error amplifier, a second buffer circuit, and a decision circuit. The auxiliary error amplifier consumes less bias current. In one embodiment, the decision circuit compares the portion of the output voltage with a bias voltage to control the gate of the N-channel MOS pass transistor, wherein the value of the bias voltage is less than the value of the reference voltage.