US 12,143,022 B2
Control circuit for controlling a power switch in a switching power supply circuit for improved EMI performance
Wei Zhao, Shenzhen (CN); Xiufeng Yu, Shenzhen (CN); and Bo Zhang, Shenzhen (CN)
Assigned to Shenzhen Kiwi Instruments Corporation, Shenzhen (CN)
Filed by Shenzhen Kiwi Instruments Corporation, Shenzhen (CN)
Filed on Jun. 24, 2022, as Appl. No. 17/848,792.
Claims priority of application No. 202110704935.8 (CN), filed on Jun. 24, 2021.
Prior Publication US 2022/0399818 A1, Dec. 15, 2022
Int. Cl. H02M 3/335 (2006.01); H02M 1/44 (2007.01)
CPC H02M 3/33507 (2013.01) [H02M 1/44 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A control circuit for controlling a power switch in a switching power supply circuit, the control circuit comprising an adaptive amplitude jitter generation circuit, a comparison circuit and a trigger circuit, wherein an input of the adaptive amplitude jitter generating circuit is configured to receive a feedback voltage signal indicative of an output of the switching power supply circuit, an output of the adaptive amplitude jitter generating circuit is coupled to a first input of the comparison circuit, a second input of the comparison circuit is configured to receive a sample voltage of the switching power supply circuit, an output of the comparison circuit is coupled to an input of the trigger circuit, and an output of the trigger circuit is coupled to a control end of the power switch, and wherein:
the adaptive amplitude jitter generating circuit is configured to generate a periodic amplitude jitter signal according to a feedback voltage;
the comparison circuit is configured to compare the sampled voltage signal with the periodic amplitude jitter signal, and generate an output signal with periodic fluctuations;
the trigger circuit provides a control signal for driving the power switch according to the output signal with periodic fluctuations and a clock signal; and
wherein the adaptive amplitude jitter generating circuit comprises a frequency jittering circuit and a superimposing circuit, and an input of the frequency jittering circuit and a first input of the superimposing circuit receives the feedback voltage, an output of the frequency jittering circuit is coupled to a second input of the superimposing circuit, and an output of the superimposing circuit is coupled to a first input of the comparison circuit, wherein:
the frequency jittering circuit is used to generate a jittering signal having periodic jitter frequency according to the feedback voltage;
the superimposing circuit is used to superimpose the feedback voltage and the jittering signal to generate the periodic amplitude jitter signal.