US 11,942,863 B2
Switching power supply including a logic circuit to control a discharge circuit
Shidong Guan, Kyoto (JP)
Assigned to Rohm Co., Ltd., Kyoto (JP)
Appl. No. 17/290,055
Filed by Rohm Co., Ltd., Kyoto (JP)
PCT Filed Oct. 28, 2019, PCT No. PCT/JP2019/042205
§ 371(c)(1), (2) Date Apr. 29, 2021,
PCT Pub. No. WO2020/095748, PCT Pub. Date May 14, 2020.
Claims priority of application No. 2018-208107 (JP), filed on Nov. 5, 2018; and application No. 2018-208110 (JP), filed on Nov. 5, 2018.
Prior Publication US 2021/0399637 A1, Dec. 23, 2021
Int. Cl. H02M 3/157 (2006.01); H02M 1/00 (2006.01); H02M 1/32 (2007.01); H02M 1/36 (2007.01)
CPC H02M 3/157 (2013.01) [H02M 1/0006 (2021.05); H02M 1/32 (2013.01); H02M 1/327 (2021.05); H02M 1/36 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A switching power supply comprising:
a switching output stage configured to generate an output voltage by rectifying and smoothing a switching voltage that is pulse-driven as an output transistor is turned on and off;
a discharge circuit configured to discharge the output voltage when the output voltage remains above a target value for a predetermined time;
an error amplifier circuit configured to receive a feedback voltage commensurate with the output voltage to generate an error voltage;
an oscillation circuit configured to generate an on signal at a predetermined switching frequency;
a slope voltage generation circuit configured to generate a slope voltage in synchronization with the on signal;
a comparison circuit configured to compare the error voltage with the slope voltage to generate an off signal;
a logic circuit configured to generate an on/off control signal in accordance with the on signal and the off signal; and
a driver circuit configured to drive the switching output stage in accordance with the on/off control signal, wherein
the logic circuit is configured to control the discharge circuit such that the discharge circuit discharges the output voltage when the off signal remains for the predetermined time at a level corresponding to an off state.