| 摘要 |
PURPOSE:To reduce power loss by setting a current supplied from the tertiary winding in reversely proportional relationship to a DC power source voltage. CONSTITUTION:A series circuit of the primary winding 3 of a transformer 2, a switching transistor (Tr)4 is connected with a DC power source 1, rectifiers 6, 7 are provided with the secondary winding 5, the tertiary winding 9 and a bypass Tr11 are provided for driving a base, controlled by a controller 13, and a constant voltage is obtained at the output terminal 12. In this case, in order to control the current I1 supplied from the winding 9, a current controller having the quaternary winding 19 electromagnetically coupled with the winding 3, Tr20, Zener diode 21 is provided. Thus, the voltage of the winding 9 of the ON period of the Tr4 is regulated to become inversely proportional to the power source voltage Ein and supplied to the base of the Tr4. Thus, the difference between the required base current IB and the current I1 passing the resistor 10 becomes small to reduce the power loss. |
