| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem with a conventional current resonance switching power supply having a structure in which a time for one period is determined by the sum of a period of a dead time for preventing through currents of upper and lower arms and an on-pulse time width that is determined by a voltage-controlled oscillator, in which a switching frequency is varied when a dead time is changed.SOLUTION: A switching power supply device includes a minimum dead time generation circuit that generates a minimum dead time period from timing for turning off an on-pulse, which is detected from a voltage of an auxiliary winding of a transformer by a differentiation circuit; and starts on-width determination means of a voltage-controlled oscillator that determines the on-width of a semiconductor switch after the minimum dead time period. |
