Nordic Semiconductor ASA
VOLTAGE REGULATOR

Abstract:

A low-dropout voltage regulator is arranged to convert an input voltage to an output voltage. The low-dropout voltage regulator comprises: an error amplifier circuit portion arranged to produce an error signal proportional to a difference between a sense voltage (Vsense) and a reference voltage (Vref), wherein the sense voltage is derived from the output voltage; a pass field-effect-transistor (MP) connected to the input voltage; and a rail-to-rail buffer circuit portion connected between the input voltage (VDD) and ground. The rail-to-rail buffer circuit portion comprises: a buffer input arranged to receive the error signal; a buffer output arranged to apply a buffer signal to the gate terminal of the pass field-effect-transistor, wherein the buffer signal is a buffered version of the error signal; and a resistive bypass arrangement (Rbypass) connected between the buffer input and the buffer output.