JPH0556631A - Dc power supply - Google Patents

Abstract

PURPOSE:To obtain a DC power supply possible to set the release starting point as desired for a rush-current preventive circuit and to an optimum time. CONSTITUTION:Voltage-dividing resistors 12, 13 are connected between the output line of a rectifier circuit and a ground, and the divided voltage is applied to the gate of a thyristor 5 constituting an rush preventive circuit while a gate capacitor 14 for adjusting the rise time of applied voltage is connected between the gate and the ground. Accordingly, when the value of the gate capacitor 14 is varied, a time when the thyristor 5 is turned ON can be changed regardless of the operation of a switching regulator circuit 10, thus setting the release starting point as desired for the rush-current preventive circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply device equipped with an inrush current prevention circuit.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram of a conventional DC power supply device, in which 1 is an AC input voltage, 2 is a rectifying bridge diode,
Reference numeral 3 is a smoothing capacitor, 4 is a rush current preventing resistor, 5 is a thyristor, 6 and 7 are bias resistors, 8 is a smoothing capacitor, 9 is a rectifying diode, 10 is a switching regulator circuit, and 11 is a transformer.

Next, the operation will be described. The AC input voltage 1 is converted into a DC voltage by the rectifying bridge diode 2 and the smoothing capacitor 3. The switching regulator circuit 10 detects this DC voltage, oscillates it, and applies it to the transformer 11. The waveform oscillated by the transformer 11 is detected by the rectifying diode 9 and smoothed by the smoothing capacitor 8, and the gate applied voltage of the thyristor 5 is set by the bias resistors 6 and 7. This voltage causes the anode of the thyristor 5 and the lead to conduct, and the operation of the inrush current prevention circuit is canceled (during normal operation). Immediately after the power is turned on, the inrush current passes through the smoothing capacitor 3,
Limited by the inrush current prevention resistor 4.

[0004]

The conventional DC power supply device is configured as described above, and it is difficult to optimally set the gate operation start time of the thyristor by the operation start time of the switching regulator circuit. . Further, when the gate start operation is slow, there is a problem that a large amount of current flows in the rush current prevention resistor and the resistor is destroyed.

The present invention has been made to solve the above problems, and a voltage can be applied to the gate of a thyristor irrespective of the operation of the switching regulator circuit, and the release point of the inrush current prevention circuit can be set. An object is to obtain a DC power supply device that can be easily set.

[0006]

In the DC power supply device according to the present invention, the voltage dividing resistor connected to the output line of the rectifying circuit and the divided voltage are input to the gate of the thyristor constituting the inrush current preventing circuit. Along with this, a capacitor for setting the gate voltage rise time connected to the gate is provided.

[0007]

In the capacitor for setting the gate voltage rise time according to the present invention, the rise time of the voltage applied to the gate of the thyristor can be changed by changing its value. The release point of the prevention circuit can be set at a desired time.

[0008]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to FIG.
Will be described. In the figure, the difference from the conventional example of FIG. 2 is that a voltage dividing resistor formed of a series body of resistors 12 and 13 is connected between the positive terminal of the smoothing capacitor 3 and ground, and this voltage dividing The connection ends of the resistors 12 and 13 are connected to the gate of the thyristor 5, and a gate voltage setting capacitor (hereinafter, referred to as “gate capacitor”) 14 that determines the rising characteristic of the gate voltage between the gate and ground. It is a point equipped with.

Next, the operation will be described. The DC voltage converted by the rectifying bridge diode 2 and the smoothing capacitor 3 is divided by the voltage dividing resistors 12 and 13,
It is added to the gate capacitor 14. By changing the value of the gate capacitor 14, the rise time of the voltage applied to the gate of the thyristor 5 can be changed.
The time for which the inrush voltage prevention circuit is released can be set arbitrarily.

Although the gate voltage of the thyristor is controlled in the above embodiment, the gate voltage of the triac may be controlled, and the same effect can be obtained.

[0011]

As described above, according to the present invention, the voltage dividing resistor is connected to the output line of the rectifier circuit, and this divided voltage is input to the gate of the thyristor which constitutes the inrush prevention circuit, and at the same time Since the rise time of the gate voltage of the thyristor can be set arbitrarily by changing the value of this gate capacitor, the optimum release point of the inrush current prevention circuit is
There is an effect that it can be set regardless of the operation of the switching regulator circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional DC power supply device.

[Explanation of symbols]

 2 Rectifier bridge diode 3 Smoothing capacitor 5 Thyristor 10 Switching regulator circuit 11 Transformer 12, 13 Voltage dividing resistor 14 Gate voltage rise time setting capacitor

Claims (1)

[Claims] 1. In a DC power supply device which converts an AC input voltage into a DC voltage and which is provided with an inrush current prevention circuit, a voltage dividing resistor connected to an output line of a rectifying circuit and the divided voltage. A DC power supply device comprising: a thyristor forming a rush prevention circuit, and a capacitor connected to the gate and setting a rise time of a gate voltage.