US 11,705,807 B2
Control circuit of power factor improvement circuit and semiconductor integrated circuit device
Satoshi Maejima, Kyoto (JP); and Takumi Fujimaki, Kyoto (JP)
Assigned to Rohm Co., Ltd., Kyoto (JP)
Filed by ROHM CO., LTD., Kyoto (JP)
Filed on Oct. 1, 2021, as Appl. No. 17/491,883.
Claims priority of application No. 2020168299 (JP), filed on Oct. 5, 2020; and application No. 2020169303 (JP), filed on Oct. 6, 2020.
Prior Publication US 2022/0109366 A1, Apr. 7, 2022
Int. Cl. H02M 1/42 (2007.01); H05B 45/355 (2020.01); H02M 1/32 (2007.01); H02M 1/08 (2006.01); H05B 45/345 (2020.01); H05B 45/3725 (2020.01)
CPC H02M 1/4208 (2013.01) [H02M 1/08 (2013.01); H02M 1/32 (2013.01); H05B 45/345 (2020.01); H05B 45/355 (2020.01); H05B 45/3725 (2020.01)] 8 Claims
OG exemplary drawing
 
1. A control circuit for a power factor improvement circuit including a DC/DC converter, the control circuit comprising:
an input voltage detection terminal, configured to receive a first voltage with a full-wave rectified waveform;
an error amplifier circuit, configured to amplify an error between a first detection voltage and a reference voltage based on an output voltage of the DC/DC converter and generate a second voltage;
an arithmetic circuit, configured to add an offset voltage to a third voltage to generate a fourth voltage, wherein the third voltage is generated by multiplying the first voltage by the second voltage;
a comparator, configured to compare a second detection voltage with the fourth voltage, wherein the second detection voltage is corresponding to a current flowing through a switching transistor of the DC/DC converter; and
a drive circuit, configured to turn on/off drive of the switching transistor according to an output of the comparator, wherein when the second detection voltage is higher than the fourth voltage, the switching transistor is turned off.