| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit that stably controls a startup operation of a switching power supply. SOLUTION: The control circuit includes: an oscillation startup control section 400 for turning on a startup switch Q301 to charge a capacitor C11, when a voltage across the capacitor reaches a startup start voltage, controlling an oscillation drive section 100 to start switching oscillation drive, and when the voltage across the capacitor drops to a first preset setting voltage after the start of switching oscillation drive by the oscillation drive section, controlling the oscillation drive section to stop the switching oscillation drive; and a startup replenishment control section 600 for, when the voltage across the capacitor drops to a second setting voltage set lower than the startup start voltage and higher than the first setting voltage after the start of switching oscillation drive by the oscillation drive section, performing switching control of turning on/off the startup switch such that the voltage across the capacitor does not drop below the second setting voltage. COPYRIGHT: (C)2012,JPO&INPIT |
