JPS6340188U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a switching power supply according to an embodiment of the present invention, Fig. 2 is a circuit diagram of another embodiment, and Fig. 3 is a circuit diagram of a switching power supply according to an embodiment of the present invention.
The figure is a circuit diagram of a conventional example. 1 is a converter transformer, 2 is an input power supply, 3 is a main winding, 4 is a base winding, 5 is an output winding, 6 is a switching transistor, 12 is a base winding induced voltage detection means, 13 is a base current supply stop means.

Claims (1)

[Claims for Utility Model Registration] A main winding whose one end is connected to the input power supply, a base winding whose one end voltage changes in accordance with voltage changes induced in the main winding, and an output winding. a converter transformer, a collector/emitter connected in series with the main winding, and the other end of the starting resistor, the other end of which is connected to the one end of the base winding and the input power source; and a direct current converting circuit connected to the output winding, the switching transistor having a base connected to the input power source via the starting resistor. In a switching power supply configured to be activated by a base current and to be switched on or off according to a change in the induced voltage in the base winding, the induced voltage in the base winding is equal to or higher than a predetermined value. base winding induced voltage detection means for detecting; and a base current supply connected to the base of the switching transistor and operating in response to the detection output of the base winding induced voltage detection means to stop supplying base current to the switching transistor. A switching power supply characterized by comprising a stopping means.