US 11,888,395 B2
Switch mode power supply with improved transient performance and control circuit thereof
Shanglin Xu, Chengdu (CN)
Assigned to Chengdu Monolithic Power Systems Co., Ltd., Chengdu (CN)
Filed by Chengdu Monolithic Power Systems Co., Ltd., Chengdu (CN)
Filed on Mar. 25, 2022, as Appl. No. 17/704,642.
Claims priority of application No. 202110392204.4 (CN), filed on Apr. 12, 2021.
Prior Publication US 2022/0329154 A1, Oct. 13, 2022
Int. Cl. H02M 3/156 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/156 (2013.01) [H02M 1/0009 (2021.05)] 17 Claims
OG exemplary drawing
 
1. A control circuit used in a switch mode power supply, wherein the switch mode power supply has a power switch and an inductor, and converts an input voltage into an output voltage, the control circuit comprising:
a transient detector configured to detect whether the switch mode power supply is in a transient state, and generate a transient detecting signal based on the detection result;
an error amplifier having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is configured to receive a first feedback voltage indicative of the output voltage and the second input terminal is configured to receive a first reference voltage, the error amplifier is configured to provide an error signal at the output terminal based on the first feedback voltage and the first reference voltage;
a first compensation network having a first resistance, the first compensation network has a first terminal and a second terminal, wherein the first terminal is coupled to the first input terminal of the error amplifier and the second terminal is coupled to the output terminal of the error amplifier;
a first resistance regulator configured to receive the transient detecting signal and regulate the first resistance based on the transient detecting signal; and
an adjusting voltage generator, wherein when the output voltage decreases and the switch mode power supply enters the transient state, the adjusting voltage generator is configured to provide an adjusting voltage with positive polarity to the second input terminal of the error amplifier, and wherein when the output voltage increases and the switch mode power supply enters the transient state, the adjusting voltage generator is configured to provide an adjusting voltage with negative polarity to the second input terminal of the error amplifier.