JPH0339382U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a switching power supply circuit with a protection circuit showing an embodiment of this invention, Fig. 2 is a waveform diagram for explaining the operation of the switching power supply circuit, and Figs. 3 and 4 are: FIG. 2 is a circuit diagram showing a conventional switching power supply circuit with a protection circuit. 1...Transformer, 2...Control circuit, 3...Rectifier circuit, 4...Overvoltage detection circuit, 6a, 6b...Output terminal, 7...Reset switch, SCR...Thyristor, _Q2 , _Q3 ... transistor.

Claims (1)

[Claims for Utility Model Registration] A DC voltage source, a switching circuit that switches the output from the DC voltage source, a transformer that receives the switched signal through an input winding and derives it from the output winding, and a transformer that receives the switched signal from the output winding. A rectifier circuit that rectifies the output, an output abnormality detection circuit that detects an abnormality in the output from the rectifier circuit, and a voltage supply level to the control circuit that is turned on in response to an abnormality detection signal of the output abnormality detection circuit. a control circuit that controls the switching operation of the switching circuit and stops the switching operation of the switching circuit when the voltage supply level becomes low due to the ON of the thyristor; a voltage level detection circuit that detects whether the voltage level supplied to the control circuit is higher or lower than a predetermined level; A switching power supply circuit with a protection circuit, characterized in that it is equipped with a reset circuit that disables the operation of the reset switch and enables the operation of the reset switch when the voltage level is lower than a predetermined level.