Patent ID: 7446515
Filing Date: 2008-11-04
Classification: G05F

Abstract:
1. An LDO (low dropout) regulator comprising: (a) a pass transistor having a first electrode coupled to produce an output voltage of the LDO regulator, a control electrode, and a second electrode coupled to receive an input voltage of the LDO regulator; (b) an error amplifier having a first input coupled to a first reference voltage and an output coupled to the control electrode of the pass transistor; (c) a first feedback circuit having an input coupled to the first electrode of the pass transistor and an output producing a first feedback voltage coupled to a second input of the error amplifier; (d) an auxiliary amplifier having a first input coupled to a second reference voltage and an output coupled to the output of the error amplifier; and (e) a second feedback circuit having an input coupled to the output of the auxiliary amplifier and an output producing a second feedback voltage coupled to a second input of the auxiliary amplifier for taking over control of the feedback in the LDO regulator at high frequencies.