| 摘要 |
<p>Provided is a synchronous rectification type forward converter comprising a commutation switch turn-on controlling switch element (Q5), which is controlled with a voltage built up at the biquadratic winding (or the auxiliary winding) (N14) of a main transformer (T1) and which performs the control of application of a control voltage to the control terminal of a commutation switch element (Q3), and a commutation switch turn-off controlling switch element (Q4) which is connected with the control terminal of the commutation switch element (Q3) and which controls, when turned on, the control terminal voltage of the commutation switch element (Q3) thereby to turn off the commutation switch element (Q3). A controlling switch element drive circuit (24) turns on, at the on-timing of a main switch element (Q1), the commutation switch turn-off controlling switch element (Q4).</p> |
