JPH11191964A - Switching power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply in which reactive power loss is prevented by means of a surge current suppression element in which countermeasures against harmonics are taken for any one of AC 100 V or AC 200 V system. SOLUTION: A switching power supply comprises an AC power supply 1 for AC 100 V and AC 200 V systems, means D and C for rectifying and smoothing the AC power supply 1 to output a DC voltage, resistors R1, R2 for dividing the DC voltage, a transistor Q1 being switched with a voltage detected by the resistors R1, R2, a relay RL being switched through switching control of the transistor Q1, and a choke coil L and a thermistor TH inserted into the AC power supply 1 wherein the DC voltage rectified and smoothed through the means D and C is divided by the resistors R1, R2. In case of an AC 100 V system, the transistor Q1 is turned off to interrupt function of the relay RL and the choke coil L and thermistor TH inserted into the AC power supply 1 are connected. In case of an AC 200 V system, the transistor Q1 is turned on to actuate the relay RL and the choke coil L and thermistor TH inserted into the AC power supply 1 are short-circuited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply, and more particularly, to a switching power supply in which a choke coil for suppressing harmonics and an inrush current suppressing element are inserted in an AC power supply line.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional switching power supply includes a choke coil L inserted into one line of an AC power supply for harmonic countermeasures, and a rectifier for rectifying and smoothing the AC power supply 1 to output a DC voltage. It comprises means D and smoothing means C, and power supply circuit 2.

The harmonic choke coil L inserted in one line of the AC power supply reduces the peak value of the AC current and widens the conduction angle by the inductance, thereby reducing the harmonic component.

Further, as shown in FIG. 5, a thermistor TH inserted in one line of an AC power supply, rectifying means D and smoothing means C for rectifying and smoothing the AC power supply 1 and outputting a DC voltage.
And a power supply circuit 2.

The thermistor TH inserted into one line of the AC power supply suppresses the rush current flowing to the AC input when the power is turned on due to its resistance value.

[0006]

In a conventional switching power supply device, measures against harmonics are performed by using an AC100V system or AC2.
Even if only one of the 00V systems is required, the choke coil for harmonic countermeasures is
It must correspond to a 00V input. When the choke coil for harmonic countermeasures is adapted from the AC100V system to the AC200V system, the current capacity at the time of input of the AC100V system and the inductance at the time of input of the AC200V system are required, so the choke coil L had to be enlarged. .

Further, since a thermistor is inserted into the AC power supply line to suppress the rush current, an invalid power loss occurs.

Therefore, an object of the present invention is to solve the problem of harmonic
An object of the present invention is to provide a switching power supply that realizes harmonic countermeasures without increasing the size of a choke coil for harmonic countermeasures when only one of the C100V system and the AC200V system is required.

Another object of the present invention is to provide a switching power supply capable of preventing the occurrence of ineffective power loss by a thermistor for suppressing an inrush current of an AC power supply line.

[0010]

In order to solve the above-mentioned problems, a switching power supply according to the present invention comprises a 100 V AC.
Rectifier and smoothing means for rectifying and smoothing AC power of a 200 V AC system and outputting a DC voltage, a power supply circuit for switching the DC voltage output from the rectifier and smoothing means, and the AC power supply and rectifier The choke coil inserted therebetween, a voltage dividing resistor connected between the smoothing means and the power supply circuit to divide the DC voltage, and the output voltage divided by the voltage dividing resistor make the AC power supply A
It is characterized by comprising detection means for detecting whether it is a C100V system or an AC200V system, and switch means for short-circuiting the choke coil with an output signal from the detection means.

In order to solve the above-mentioned problems, a switching power supply according to the present invention comprises a choke coil and an inrush current suppressing element inserted between the AC power supply and rectifying means, and an output signal of the detecting means. And a switch means for short-circuiting the choke coil and the rush current suppressing element.

[0012]

Next, a switching power supply according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a switching power supply according to a first embodiment of the present invention.

As shown in FIG. 1, a switching power supply according to a first embodiment of the present invention comprises an AC power supply 1 for supplying AC 100 V and AC 200 V power, and a rectifying and smoothing DC power supply for the AC power supply 1. A rectifier D and a smoother C for outputting a voltage, and resistors R1 and R1 for dividing a DC voltage.
R2, a transistor Q1 for switching control based on the voltages detected by the resistors R1 and R2, a relay RL for switching connection by switching control of the transistor Q1, a choke coil L inserted in one line of the AC power supply, and a thermistor TH. Is done.

The operation of the switching power supply according to the first embodiment of the present invention will be described with reference to the drawings.

The operation of the switching power supply according to the first embodiment of the present invention, as shown in FIG.
The DC voltage rectified and smoothed by the rectifying means D and the smoothing means C is divided by the resistors R1 and R2. When an AC 100 V system is input, the transistor Q1 remains OFF and no current flows through the winding and the relay RL does not operate.

As a result, while the choke coil L and the thermistor TH inserted in one line of the AC power supply remain connected, the transistor Q1 is turned on when the AC 200 V system is next input, and current flows through the winding of the relay RL. And the choke coil L and the thermistor TH inserted into one line of the AC power supply are short-circuited.

Next, a switching power supply according to a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing a switching power supply according to a second embodiment of the present invention.

As shown in FIG. 2, a switching power supply according to a second embodiment of the present invention includes an AC power supply 1 for supplying AC 100 V and AC 200 V power, and a rectifying and smoothing DC power supply for the AC power supply 1. A rectifier D and a smoother C for outputting a voltage, and resistors R1 and R1 for dividing a DC voltage.
R2, a transistor Q1 for switching control based on voltages detected by the resistors R1 and R2, a relay RL for switching connection by switching control of the transistor Q1, and a choke coil L inserted in one line of the AC power supply.

The operation of the switching power supply according to the second embodiment of the present invention will be described with reference to the drawings.

The operation of the switching power supply according to the first embodiment of the present invention, as shown in FIG.
The DC voltage rectified and smoothed by the rectifying means D and the smoothing means C is divided by the resistors R1 and R2. When an AC 100 V system is input, the transistor Q1 remains OFF and no current flows through the winding and the relay RL does not operate.

As a result, the choke coil L inserted into one line of the AC power supply remains connected,
When the V system is input, the transistor Q1 turns ON,
A current flows through the winding of the relay RL to operate, and the choke coil L inserted into one line of the AC power supply is short-circuited.

Next, a switching power supply according to a third embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram of a switching power supply according to a third embodiment of the present invention.

As shown in FIG. 3, a switching power supply according to a third embodiment of the present invention includes an AC power supply 1 for supplying AC 100 V and AC 200 V power, and a rectifying and smoothing DC power supply for the AC power supply 1. A rectifier D and a smoother C for outputting a voltage, and resistors R1 and R1 for dividing a DC voltage.
R2, a transistor Q1 that performs switching control based on voltages detected by the resistors R1 and R2, a transistor Q2 that inverts a switching control signal of the transistor Q1 and performs switching control, and a relay that switches connection by switching control of the transistor Q2. RL, a choke coil L inserted into one line of the AC power supply, and a thermistor TH.

The operation of the switching power supply according to the third embodiment of the present invention will be described with reference to the drawings.

The operation of the switching power supply according to the third embodiment of the present invention, as shown in FIG.
DC voltage rectified and smoothed by the rectifying means D and the smoothing means C is divided by the resistors R1 and R2. When the AC 200 V system is input, the transistor Q1 remains ON and the transistor Q2 remains OFF, so that no current flows through the winding and the relay RL is turned off. Do not work.

As a result, while the choke coil L and the thermistor TH1 inserted in one line of the AC power supply remain connected, the transistor Q1 is turned off and the transistor Q2 is turned on when the AC100V system is next input, and the winding of the relay RL is turned on. When a current flows through the line, the line operates and the choke coil L and the thermistor TH inserted into one line of the AC power supply are short-circuited.

Next, a switching power supply according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a block diagram showing a switching power supply according to a fourth embodiment of the present invention.

As shown in FIG. 4, a switching power supply according to a fourth embodiment of the present invention comprises an AC power supply 1 for supplying 100 V AC and 200 V AC power, and a rectifying and smoothing DC power supply for the AC power supply 1. A rectifier D and a smoother C for outputting a voltage, and resistors R1 and R1 for dividing a DC voltage.
R2, a transistor Q1 that performs switching control based on voltages detected by the resistors R1 and R2, a transistor Q2 that inverts a switching control signal of the transistor Q1 and performs switching control, and a relay that switches connection by switching control of the transistor Q2. RL and a choke coil L inserted in one line of the AC power supply.

The operation of the switching power supply according to the fourth embodiment of the present invention will be described with reference to the drawings.

The operation of the switching power supply according to the fourth embodiment of the present invention, as shown in FIG.
DC voltage rectified and smoothed by the rectifying means D and the smoothing means C is divided by the resistors R1 and R2. When the AC 200 V system is input, the transistor Q1 remains ON and the transistor Q2 remains OFF, so that no current flows through the winding and the relay RL is turned off. Do not work.

As a result, while the choke coil L inserted in one line of the AC power supply remains connected,
When the V system is input, the transistor Q1 is turned off and the transistor Q2 is turned on, a current flows through the winding of the relay RL, and the choke coil L inserted into one line of the AC power supply is short-circuited.

[0036]

As described above, according to the switching power supply of the present invention, when harmonic countermeasures are required only in one of the AC 100 V system and the AC 200 V system, the input voltage system in which the harmonic countermeasures are required is provided. Since the harmonic countermeasure can be implemented only at the time, there is an effect that the choke coil for the harmonic countermeasure does not need to be enlarged.

Further, according to the switching power supply of the present invention, there is an effect of preventing the occurrence of an invalid power loss due to the rush current suppressing element of the AC power supply line of the input voltage system which does not require measures against harmonics.

[Brief description of the drawings]

FIG. 1 is a block diagram of a switching power supply according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a switching power supply according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a switching power supply according to a third embodiment of the present invention.

FIG. 4 is a block diagram of a switching power supply according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a conventional switching power supply device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 AC power supply 2 Power supply circuit C Smoothing means D Rectifying means L Choke coil TH Inrush current suppressing element (Thermistor) Q1 Detecting means (Transistor) R1, R2 Voltage dividing resistor Q2 Inverting means (Transistor) R3, R4 Inverting means (Resistance) RL Switch means (relay)

Claims (2)

[Claims] 1. A rectifying means and a smoothing means for rectifying and smoothing an AC power supply of 100 V AC and 200 V AC to output a DC voltage, a power supply circuit for switching the DC voltage output from the rectification means and the smoothing means, A choke coil inserted between the AC power supply and the rectifying means, a voltage dividing resistor connected between the smoothing means and the power supply circuit for dividing the DC voltage, and an output voltage divided by the voltage dividing resistor, The AC power supply is AC100V or AC200
A switching power supply device comprising: a detecting means for detecting whether the system is a V-system; and a switch means for short-circuiting the choke coil with an output signal from the detecting means. 2. A choke coil and an inrush current suppressing element inserted between the AC power supply and the rectifying means, and a switch means for short-circuiting the choke coil and the inrush current suppressing element by an output signal of the detecting means. The switching power supply device according to claim 1, wherein: