US 12,438,448 B2
Switching control circuit and power supply circuit
Yukihiro Yaguchi, 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. 18/357,545.
Claims priority of application No. 2022-134343 (JP), filed on Aug. 25, 2022.
Prior Publication US 2024/0072661 A1, Feb. 29, 2024
Int. Cl. H02M 1/42 (2007.01); H02M 1/00 (2006.01)
CPC H02M 1/4225 (2013.01) [H02M 1/0009 (2021.05); H02M 1/0025 (2021.05); H02M 1/4216 (2013.01); H02M 1/0032 (2021.05)] 8 Claims
OG exemplary drawing
 
1. A switching control circuit for a power supply circuit that includes
an inductor to which a voltage in accordance with an alternating current (AC) voltage is applied, and
a transistor controlling an inductor current flowing through the inductor,
the power supply circuit generating an output voltage from the AC voltage, the switching control circuit being configured to control switching of the transistor, the switching control circuit comprising:
an ON signal output circuit that
outputs an ON signal to turn on the transistor in response to the inductor current reaches a predetermined current, when a feedback voltage in accordance with the output voltage indicates that the
output voltage is lower than a first level, and outputs the ON signal every first cycle when the feedback voltage indicates that the output voltage is higher than the first level;
an OFF signal output circuit that outputs an OFF signal to turn off the transistor based on the feedback voltage; and
a driver circuit that drives the transistor based on the ON signal and the OFF signal, wherein
the first cycle is longer than a second cycle, which is a cycle of the ON signal when the output voltage is lower than the first level.