| 摘要 |
PURPOSE:To obtain an overcurrent protective circuit by providing a transformer having a primary winding inserted between a DC input terminal and a chopper, and means for applying a rectified secondary voltage of the transformer and an output current from + output terminal of the chopper to an overcurrent protective terminal of the chopper. CONSTITUTION:Since a voltage doubler rectifier is connected with the primary winding of a transformer 7, voltage across a resistor R1 connected in parallel with the secondary winding 72 of the transformer 7 is maintained at Q-Q' even during function of overcurrent protection, and energy supply by the OFF pulses of a chopper circuit 5 increases in the direction of negative voltage. ON width becomes narrower as a load becomes heavier, and the energy Q' to be fed according to the ON width from + output terminal of the chopper circuit 5 through a resistor R2 increases correspondingly thus maintaining the potential at an overcurrent protective input terminal F at a negative level at all times. |
