US 12,301,119 B2
Isolated switching regulators with smart power supply and the method thereof
Hui Li, Hangzhou (CN); and Siran Wang, Hangzhou (CN)
Assigned to Chengdu Monolithic Power Systems Co., Ltd., Sichuan (CN)
Filed by Chengdu Monolithic Power Systems Co., Ltd., Chengdu (CN)
Filed on Nov. 29, 2022, as Appl. No. 18/070,853.
Claims priority of application No. 202111472841.9 (CN), filed on Dec. 3, 2021.
Prior Publication US 2023/0179104 A1, Jun. 8, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/33576 (2013.01) [H02M 1/007 (2021.05)] 14 Claims
OG exemplary drawing
 
1. An isolated switching regulator, comprising:
a primary circuit, configured to receive an input voltage, the primary circuit having a primary power switch coupled to a primary winding of a transformer;
a secondary circuit, configured to provide an output voltage, the secondary circuit having a secondary power switch coupled to a secondary winding of the transformer;
a control circuit, including a loop controller and a driver, wherein the loop controller is configured to provide a control signal, and the driver is configured to generate a drive signal to control the secondary power switch in response to the control signal;
a first capacitor, configured to store a first power supply to power the loop controller, wherein the first power supply is configured to be derived from the output voltage; and
a second capacitor, configured to store a second power supply to power the driver, wherein the second power supply is configured to be derived from the output voltage or from a voltage across the secondary winding; wherein:
when the output voltage is operable to provide a sufficient power supply to the driver, the second power supply is configured to be derived from the output voltage; and
when the output voltage is operable to provide an insufficient power supply to the driver, the second power supply is configured to be derived from the voltage across the secondary winding.