| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device in which an overcurrent protective circuit can be surely and safely operated, without largely increasing its cost. SOLUTION: The switching power supply device comprises an insulating transformer 1 having a primary winding and a secondary winding, a switching element 2 with its one end connected to one end of the primary winding, rectification smoothing sections 14, 17 connected to the secondary winding, a control unit 22 for controlling the switching element corresponding to the DC output voltage of the rectification smoothing sections, a current detection section 27 for detecting the current output from the rectification smoothing sections, and an overcurrent protective circuit for turning off the switching element when the detected output of the current detection section exceeds a prescribed value, wherein the overcurrent protective circuit is configured to switch the prescribed value corresponding to the DC output voltage of the rectification smoothing sections, so that the DC power is input from the other end of the primary winding and the other end of the switching element to output the DC power from rectification smoothing sections. COPYRIGHT: (C)2009,JPO&INPIT |
