| 摘要 |
PURPOSE:To obtain a stable output by further providing the tertiary winding in a high frequency transformer, and supplying a DC current thereto in a no load state, thereby increasing the operating range. CONSTITUTION:An output voltage V and a reference voltage E are input to the first comparator 12, and an error signal is input to the second comparator 14. The frequency of the current which passes a diode 6 is detected by a detector 15, input to the comparator 14, the output is applied to a pulse generator 7, and the prescribed DC voltage V is obtained at an output terminal 11 by controlling a transistor 4. In this case, the tertiary winding 3c is provided in a high frequency transformer 2, and the third comparator 16 is further provided. Thus, the output of the comparator 12 is compared with the output V of the second reference voltage source 17, and when a load 21 becomes light, a DC current is supplied through a transistor 18 to the winding 3c. Thus, the oscillating operation of the generator 7 does not stop even if becoming no load state, and the controllable operating range can be increased. |
