JPH033192U - - Google Patents

Description

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.
2 is a diagram for explaining the operation of the constant forward current circuit in FIG. 1, and FIG. 3 is a connection diagram of a voltage detection circuit and a current control circuit provided in place of the constant current circuit in FIG. Figure 4 is a diagram for explaining its operation, Figure 5 is a block diagram of a conventional DC power supply equipped with an inrush current limiting function, and Figure 6 is a diagram for explaining the operation of the circuit shown in Figure 5. FIG. 10... Inrush current limiting circuit, 20... Main transformer, 30... Rectifying and smoothing circuit, 40... Pulse width control circuit, 50... Rectifying and smoothing circuit, 60... Constant current circuit, 70... Voltage detection circuit.

Claims (1)

[Claims for Utility Model Registration] (1) The input AC power source is rectified and smoothed, and the DC voltage is turned on/off by a switching element and applied to the primary winding of the transformer, and the signal generated in the secondary winding is In a power supply device equipped with a switching power supply that obtains a DC voltage by rectification and smoothing, and an inrush current limiting circuit in which a parallel circuit of a current limiting resistor and a switching element is inserted in a current path leading from an input AC power supply to a switching power supply, a transformer is used. A circuit for rectifying and smoothing the output generated in the winding provided in the circuit, and a constant current circuit for making the output of the rectifying and smoothing circuit a constant current are provided, and the power failure current from the power failure current circuit is used as a drive signal for the switch element. An inrush current limiting circuit for a DC power supply, characterized in that: (2) Switching that rectifies and smoothes the input AC power supply, turns the DC voltage on and off using a switching element, applies it to the primary winding of the transformer, and rectifies and smoothes the signal generated in the secondary winding to obtain the DC voltage. In a power supply device equipped with a power source and an inrush current limiting circuit in which a parallel circuit of a current limiting resistor and a switching element is inserted in a current path leading from an input AC power source to a switching power source, the output generated in the winding of the transformer is a rectifying and smoothing circuit; a voltage detecting circuit that detects when the output voltage of the rectifying and smoothing circuit reaches a predetermined voltage; and a current control circuit that controls the current supplied to the switch element according to the output of the voltage detecting circuit. Inrush current limiting circuit for DC power supply.