US 12,445,057 B2
Switching control circuit and power supply circuit
Nobuyuki Hiasa, Matsumoto (JP)
Assigned to FUJI ELECTRIC CO., LTD., Kawasaki (JP)
Filed by FUJI ELECTRIC CO., LTD., Kawasaki (JP)
Filed on Jul. 24, 2023, as Appl. No. 18/357,330.
Claims priority of application No. 2022-128231 (JP), filed on Aug. 10, 2022.
Prior Publication US 2024/0055974 A1, Feb. 15, 2024
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 1/10 (2006.01)
CPC H02M 3/33507 (2013.01) [H02M 1/0009 (2021.05); H02M 1/0025 (2021.05); H02M 1/10 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A switching control circuit for a power supply circuit that is a first power supply circuit or a second power supply circuit, the power supply circuit being configured to receive an alternating current (AC) voltage and to generate an output voltage from the AC voltage, and including
an inductor configured to receive a first rectified voltage corresponding to the AC voltage, and
a transistor configured to control an inductor current flowing through the inductor,
the switching control circuit being configured to control switching of the transistor, the switching control circuit comprising:
an identification circuit configured to identify whether an effective value of the AC voltage is a first level or a second level lower than the first level;
a first comparator circuit configured to,
in a first case in which the effective value is the first level and the power supply circuit is the first power supply circuit, compare the inductor current with a first current value, and
in a second case in which the effective value is the second level and the power supply circuit is the first power supply circuit or the second power supply circuit, compare the inductor current with a second current value larger than the first current value; and
a driver circuit configured to drive the transistor, based on the inductor current and the output voltage, wherein
the driver circuit is configured to turn off the transistor, in response to the inductor current exceeding a current value to be compared out of the first current value and the second current value.