| 摘要 |
PURPOSE:To contrive the long life of a gas laser power source by providing a constant-voltage circuit for supplying a drive circuit power source for a switching element, a commutation circuit which commutates an output voltage of a switching transformer auxiliary winding during the switching operation, and a diode which prevents the operation of said constant-voltage circuit during the switching operation. CONSTITUTION:When a voltage is supplied to an A.C. input power source line, a commutation circuit 2 commutates it to supply a D.C. voltage. This D.C. voltage is lowered by a constant-voltage circuit to a proper value as a power source voltage of a drive circuit 6 and it is supplied to the drive circuit 6 through a diode 13. During that process, for the quantity of voltage drop, a product with the voltage supplied to the drive circuit 6 is generated as a loss. If a Zener voltage of a Zener diode 12 is predetermined to be higher than an emitter voltage of a transistor 8 within a proper range as a source voltage of the drive circuit 6, a current flowing out of an emitter of the transistor 8 is prevented by the diode 13 during the operation of the switching circuit so that a loss produced in the transistor 8 is eliminated. |
