| 摘要 |
A synchronous rectification switching power source device accurately determines the timing of the turning off of a synchronous rectifier switching element regardless of the state of the load, and a synchronous rectification period is utilized to the maximum. The switching power source device is configured of a main FET connected to a primary winding of a transformer, a snubber circuit connected to the primary winding, a synchronous rectifier FET connected to a secondary winding of the transformer, a diode connected to the synchronous rectifier FET, a synchronous rectifier FET drain voltage detection unit, an output voltage detection unit, and a drive control unit. The drive control unit accurately determines the timing of the turning off of the synchronous rectifier switching element using a unit that detects the on/off state of the main FET, a variable pulse generator unit, a count value generated by a counter unit, and a threshold value. |
