Patent ID: 11942863
Assignee: ROHM CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. 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;
a driver circuit configured to drive the switching output stage in accordance with the on/off control signal, and
a bootstrap circuit configured to generate a boosted voltage by adding up the switching voltage and a terminal-to-terminal voltage across a boot capacitor to feed the boosted voltage to the driver circuit, wherein
the logic circuit is configured to control the discharge circuit such that the discharge circuit momentarily turns on a discharge transistor connected between an application terminal for the switching voltage and a grounded terminal every off period of the output transistor.