Patent ID: 8922181

Claim:
A power control circuit comprising: a control circuit configured to perform a soft start operation before a normal operation and to correct a switching frequency, the control circuit comprising: a counter circuit configured to measure a period of the soft start operation and to generate count data; a digital-to-analog (D/A) conversion circuit configured to convert the count data to a soft start voltage; a first comparator circuit configured to compare the soft start voltage, a first reference voltage, and an output voltage and to output a determination signal to a pulse generator based on the comparison; a pulse generator configured to generate a driving signal based on a duty ratio; a phase generator configured to detect a time difference between a cycle of a reference clock signal and a cycle of a count signal; and an ON-time setting circuit configured to reduce the time difference detected by the phase comparator; and a converter circuit configured to step down an input voltage by controlling a transistor based on the driving signal from the control circuit.