US 12,294,301 B2
Power supply circuit and light-emitting diode (LED) driving system using power supply circuit
Guoqiang Liu, Hangzhou (CN); and Yingyan He, Hangzhou (CN)
Assigned to Joulwatt Technology Co., Ltd., Hangzhou (CN)
Filed by Joulwatt Technology Co., Ltd., Hangzhou (CN)
Filed on Apr. 24, 2023, as Appl. No. 18/138,353.
Claims priority of application No. 202210428829.6 (CN), filed on Apr. 22, 2022.
Prior Publication US 2023/0344341 A1, Oct. 26, 2023
Int. Cl. H02M 3/158 (2006.01); H02M 1/00 (2007.01); H05B 45/10 (2020.01); H05B 45/3725 (2020.01); H05B 45/395 (2020.01)
CPC H02M 3/158 (2013.01) [H02M 1/0045 (2021.05); H05B 45/10 (2020.01); H05B 45/3725 (2020.01); H05B 45/395 (2020.01)] 18 Claims
OG exemplary drawing
 
1. A power supply circuit configured to provide a supply voltage for a load and comprising a linear conversion circuit, a first capacitor, and a direct current—direct current (DC-DC) conversion circuit, wherein an alternating current (AC) input signal is rectified to form a first rectified voltage;
the linear conversion circuit receives the first rectified voltage and has an output terminal connected to the first capacitor; and after the power supply circuit is started, the linear conversion circuit controls the first rectified voltage to charge the first capacitor in a time period when the first rectified voltage is near a trough; and
the DC-DC conversion circuit receives a first capacitor voltage and performs power conversion to output the supply voltage, wherein
the linear conversion circuit controls a charging of the first capacitor to start when a first rectified voltage sampled signal drops to a first threshold or
the linear conversion circuit controls the charging of the first capacitor to start when the first rectified voltage sampled signal drops to the first threshold or a first capacitor voltage sampled signal is less than a third threshold.