| 摘要 |
PURPOSE:To enable to eliminate power loss of a starting resistor by providing a starting transistor for opening or closing a starting current flowed to the starting resistor, and controlling the transistor by the presence or absence of an output of a converter power source. CONSTITUTION:When a switch 2 is closed, a base current is flowed to a starting resistor 3, a starting transistor 14, a resistor 15, and a diode 16 in this order. Thus, the transistor 14 is conducted, a starting current is flowed to the base of a switching transistor 4, a converter power source starts starting, and a pulse voltage is generated at an output winding 10. This pulse voltage is rectified, smoothed by a diode 11 and a capacitor 12, and a DC current is supplied to a load 13, and when the output voltage corresponding to the base voltage of the transistor 14 gradually becomes high, the base current is hardly flowed, and when the base potential becomes the vicinity of the potential of a DC power source 1, the transistor 14 is completely interrupted, and the starting current flowed through the resistor 3 is hardly flowed, the starting circuit is stopped, and the power loss of the resistor 3 can be lessened. |
