US 12,032,397 B2
Low dropout regulator with amplifier having feedback circuit
Hsueh-Yu Kao, Hsinchu (TW); and Yi-Shao Chang, Hsinchu (TW)
Assigned to REALTEK SEMICONDUCTOR CORPORATION, Hsinchu (TW)
Filed by Realtek Semiconductor Corporation, Hsinchu (TW)
Filed on Sep. 10, 2021, as Appl. No. 17/471,257.
Claims priority of application No. 110105972 (TW), filed on Feb. 20, 2021.
Prior Publication US 2022/0269296 A1, Aug. 25, 2022
Int. Cl. G05F 1/575 (2006.01); G05F 1/565 (2006.01); G05F 3/26 (2006.01)
CPC G05F 1/575 (2013.01) [G05F 1/565 (2013.01); G05F 3/262 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A low dropout regulator, comprising:
an output circuit comprising a signal input end and a signal output end, wherein the signal input end is configured to receive an input voltage, and the signal output end is configured to output an output voltage; and
an amplifier comprising:
a first stage amplifier circuit comprising a positive input end, a negative input end, a positive output end and a negative output end;
a second stage amplifier circuit comprising an input end and an output end, wherein the input end and the positive output end are coupled at a first node, and the output end is coupled to the output circuit;
a first feedback circuit electrically connected between the negative output end and the output end, and configured to provide a positive feedback, wherein the first feedback circuit comprises a first capacitor and a third resistor, the first capacitor is coupled to the negative output end, and the third resistor is coupled between the first capacitor and the output end; and
a second feedback circuit electrically connected between the first node and the output end.