US 12,487,622 B2
Voltage regulator and signal amplifying circuit
Li-Lung Kao, Hsinchu (TW)
Assigned to Realtek Semiconductor Corporation, Hsinchu (TW)
Filed by Realtek Semiconductor Corporation, Hsinchu (TW)
Filed on Mar. 31, 2023, as Appl. No. 18/193,652.
Claims priority of application No. 111116557 (TW), filed on Apr. 29, 2022.
Prior Publication US 2023/0350445 A1, Nov. 2, 2023
Int. Cl. G05F 1/575 (2006.01); H03F 3/45 (2006.01)
CPC G05F 1/575 (2013.01) [H03F 3/45179 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A voltage regulator, comprising:
an error amplifier circuit, comprising:
a first-stage amplifier, comprising:
a first current source, coupled with a first power terminal;
a fully differential amplifier circuit, coupled between the first current source and a second power terminal, and configured to amplify a difference between an output feedback signal and a reference signal to generate a first differential signal and a second differential signal; and
a common mode feedback circuit, configured to provide a common mode feedback signal to the fully differential amplifier circuit so as to stabilize a direct-current common mode voltage of the first differential signal and the second differential signal, wherein the common mode feedback circuit comprises:
a first amplifier circuit, configured to amplify a difference between the first differential signal and a common mode control signal to generate a first output current; and
a second amplifier circuit, configured to amplify a difference between the second differential signal and the common mode control signal to generate a second output current,
wherein the common mode feedback circuit is configured to generate the common mode feedback signal according to the first output current and the second output current;
a second-stage amplifier, configured to amplify a difference between the first differential signal and the second differential signal to generate an output control signal;
an output stage circuit, coupled with the first power terminal and comprising a switch, wherein the switch is configured to generate an output signal at an output node according to the output control signal; and
an output feedback path, coupled with the output node and the error amplifier circuit, and configured to generate the output feedback signal according to the output signal.