Patent ID: 8729877

Claim:
An apparatus including a linear regulator comprising: a first capacitor; a plant that receives an input current and an input voltage and that is coupled to the linear regulator, wherein the plant includes the first capacitor; a first controller including a comparator that is coupled to the plant and that controls the plant, wherein the output of the comparator is coupled to a pulse width modulator (PWM), wherein an output of the pulse width modulator is coupled to a driver circuit of the plant; a switch network that is coupled to the first controller and that receives one of a first reference voltage and a second reference voltage, wherein the second reference voltage is greater than the first reference voltage; and a second controller that provides a control signal to the switch network, wherein the second controller enables the switch network to provide the second reference voltage to the first controller when the linear regulator is disabled so as to overcharge the first capacitor, and wherein the first capacitor charges a second capacitor during a first portion of a startup period for the linear regulator, and wherein the second controller enables the switch network to provide the first reference voltage to the first controller during a second portion of the startup period, wherein the linear regulator further comprises a low dropout regulator (LDO) having: a transistor having a first passive electrode, a second passive electrode, and a control electrode, wherein the first passive electrode of the transistor is coupled to the plant; an amplifier having a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the amplifier receives a third reference voltage, and wherein the second input terminal of the amplifier is coupled to the second passive electrode of the transistor, and wherein the output terminal of the amplifier is coupled to the control electrode of the transistor; and the second capacitor is coupled to the second passive electrode of the transistor.