JPH11196529A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply which prevents occurrence of inrush current when power supply is restored after the occurrence of a momentary power failure. SOLUTION: A power supply comprises five major elements; a TRIAC TR1 connected between an AC power supply 1 and a capacitor which transmits or breaks an input from an AC power supply 1, a transistor Q1 which switches on or off a parallel circuit to a resistor R1 and the TRIAC TR1, a resistor R3 connected in series to the parallel circuit between the AC power supply 1 and capacitor C1 which detects the presence of an input from the AC power supply, an input control circuit 11 which compares the input voltage detected with this resistor R3 with a given reference voltage Vr to output an input transmission signal at the time when the input voltage changes from a no- detection state to the state exceeding the given reference voltage Vr, and a delay drive circuit 12 based on the input transmission signal from the input control circuit 11 which switches on the TRIAC TR1 with a given delay time to lead the AC input from the AC power supply 1 to the capacitor C1 without routing the resistor R1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device,
More specifically, the present invention relates to a power supply device having a function of limiting an inrush current generated at the time of an instantaneous power failure.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional power supply device, and FIG. 5 shows operation waveforms of various parts of the conventional power supply device.

[0003] A conventional power supply device shown in FIG.
A parallel circuit of a triac TR1 and a resistor R1 is connected in series, and a voltage supplied from the AC power supply 1 through this series circuit is rectified by a bridge rectifier circuit composed of diodes D1 to D4, and further rectified by a smoothing capacitor C1. A predetermined DC voltage is output after smoothing.

A DC / D converter is connected in parallel with the smoothing capacitor C1.
The C / DC converter 2 is connected, performs DC-DC conversion by the DC / DC converter 2, and supplies a predetermined DC voltage to the load R.

The DC / DC converter 2 has a primary winding N
1, a switching transformer T having a secondary winding N2 and an auxiliary winding N3, a switching element S for switching a DC voltage supplied to the primary winding N1, and a secondary winding N2.
A smoothing diode D0 and a smoothing capacitor C0 for smoothing a pulse voltage induced in the smoothing capacitor C0.
And the load R is connected in parallel.

Further, a rectifying / smoothing circuit comprising a smoothing diode D56 and a smoothing capacitor C53 is connected to the auxiliary winding N3. The triac TR1 is supplied to the gate of the triac TR1 via a resistor R54 to perform an on / off operation of the triac TR1.

In this conventional power supply device, a parallel circuit of the resistor R1 and the triac TR1 is connected to an input line from the AC power supply 1 in order to prevent an inrush current when the AC power supply 1 is turned on. After that, the triac TR1 is turned on after stabilization, so that resistance loss due to the resistance R1 does not occur.

In general, the gate of the triac TR1 is driven by using the induced voltage of the auxiliary winding N3 of the switching transformer T.

[0009]

However, the conventional example shown in FIG. 4 has the following problems.

[0010] As shown in FIG.
If the input is interrupted due to an instantaneous power failure, for example, when the electrical angle returns to 270 degrees, a large voltage difference exists between the AC input immediately after the recovery and the voltage across the smoothing capacitor C1. As an input current to the circuit, as shown in FIG. 5, an input current having a very large peak value which is limited by the resistance value of the resistor R1 and the line impedance (usually 1 Ω or less) flows.

The input current having a large peak value may cause a failure such as an erroneous trip of a breaker or the like used in the input power distribution system, which may be a factor that makes it impossible to restart the operation of the power supply device itself.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply device capable of preventing occurrence of an inrush current when power is turned on or returning after an instantaneous power failure has occurred, and which can exhibit a stable operation. .

[0013]

According to the first aspect of the present invention,
In a power supply device that rectifies and smoothes an AC input from an AC power supply, converts the DC input into a DC voltage by a switching power supply circuit having an input capacitor, and outputs the DC voltage, an ON / OFF drive connected between the AC power supply and the input capacitor is performed. A parallel circuit of an input transmission blocking element for transmitting and blocking input from an AC power supply, and an input suppression element for suppressing input current, and an input transmission blocking element for driving the input transmission blocking element on and off A drive circuit, an input detection circuit that detects the presence or absence of an input from the AC power supply connected in series with the parallel circuit between the AC power supply and an input capacitor, and an input voltage detected by the input detection circuit;
An input control circuit that compares the input transfer signal from the input control circuit with a predetermined reference voltage and outputs an input transfer signal when the input voltage changes from a state where the input voltage is not detected to a state exceeding the predetermined reference voltage; Based on the delay, the input transmission cut-off element is turned on through the input transmission cut-off element driving circuit with a predetermined delay time, and the AC input from the AC power supply is led to the input capacitor side without passing through the input suppression element. A driving circuit.

According to the present invention, an input transmission signal is output when the input voltage changes from a state where the input voltage is not detected to a state exceeding a predetermined reference voltage, and based on the input transmission signal from the input control circuit, a predetermined signal is output. The input transmission cut-off element is turned on via the input transmission cut-off element driving circuit with the delay time of, and the AC input from the AC power supply is led to the input capacitor side without passing through the input suppression element. It is possible to prevent the occurrence of an inrush current at the time of turning on or at the time of return after the occurrence of an instantaneous power failure, and to exert a stable operation.

According to a second aspect of the present invention, there is provided a power supply device for rectifying and smoothing an AC input from an AC power supply by a rectifying and smoothing circuit, and converting and outputting the DC voltage by a switching power supply circuit having an input capacitor. A parallel circuit of an input transmission cut-off element connected between the smoothing circuit and the input capacitor, which transmits and cuts off the input from the AC power supply by being turned on and off, and an input suppression element which suppresses the input current. Turning on the input transmission cutoff element,
An input transmission cutoff element driving circuit that is driven off, an input detection circuit that detects the presence or absence of an input from the AC power supply connected in series with the parallel circuit between the rectifying and smoothing circuit and the input capacitor, An input control circuit for comparing an input voltage to be detected with a predetermined reference voltage and outputting an input transmission signal when the input voltage changes from a state where the input voltage is not detected to a state exceeding a predetermined reference voltage; Based on the input transmission signal from the circuit, the input transmission cutoff element is turned on through the input transmission cutoff element driving circuit with a predetermined delay time, and the DC voltage input from the AC power supply and output from the rectifying and smoothing circuit is output. And a delay drive circuit for guiding the input capacitor side without passing through the input suppressing element.

According to the present invention, the presence or absence of the input of the DC voltage is detected between the rectifying and smoothing circuit and the input capacitor, and when the input voltage is changed from a state where the input voltage is not detected to a state exceeding the predetermined reference voltage. Output the input transmission signal,
Based on the input transmission signal from the input control circuit, the input transmission interrupting element is turned on by a predetermined delay time via the input transmission interrupting element driving circuit, and the DC voltage is applied to the input suppressing element by the input transmission interrupting element. Therefore, when the power is turned on or when the power is restored after an instantaneous power failure, the occurrence of an inrush current can be prevented, and a stable operation can be exhibited.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) As shown in FIG. 1, a power supply device according to Embodiment 1 includes, in an AC power supply 1, a triac TR1 which is an input transmission cutoff element, and an input current suppression for suppressing an input current. A parallel circuit with a resistor R1 as an element is connected in series, and a voltage supplied from the AC power supply 1 through the parallel circuit is passed through a resistor R3 as an input detection circuit to a bridge rectifier circuit including diodes D1 to D4 and a next stage. Is input to a rectifying and smoothing circuit comprising a smoothing capacitor C1 functioning as an input capacitor to the rectifying and smoothing circuit, rectified by the rectifying and smoothing circuit, and output as a predetermined DC voltage.

A DC / DC converter 2 for performing a switching operation and a rectifying / smoothing operation is connected to a stage subsequent to the smoothing capacitor C1. The DC / DC converter 2 performs DC-DC conversion, and a predetermined DC voltage is applied to a load R. Is supplied.

The DC / DC converter 2 has a primary winding N
1, a switching transformer T having a secondary winding N2 and an auxiliary winding N3, a switching element S for switching a DC voltage supplied to the primary winding N1, and a secondary winding N2.
A smoothing diode D0 and a smoothing capacitor C0 for smoothing a pulse voltage induced in the smoothing capacitor C0.
And the load R is connected in parallel.

Further, to the auxiliary winding N3, diodes D5 and D6, which are DC voltage supply circuits, smoothing capacitors C2 and C3, three-terminal regulators IC1 and IC2, and smoothing capacitors C4 and C5 are connected. A predetermined DC voltage VCC is supplied to the three-terminal regulator IC1.

The gate of the triac TR1 is connected via a resistor R4 to the collector of a transistor Q1 as an input transmission cutoff element driving circuit, and the output of the three-terminal regulator IC2 is connected to the emitter of the transistor Q1. I have. A resistor R2 is connected between the gate of the triac TR1 and the output terminal of the triac TR1.

As shown in FIG. 1, the power supply unit compares the voltage of the AC input detected by the resistor R3 with a predetermined reference voltage (Vr, -Vr), and detects no input voltage. From the state, a predetermined reference voltage (Vr, -Vr
), An input control circuit 11 that outputs an input transmission signal when the state changes to a state exceeding the above condition. Based on the input transmission signal from the input control circuit 11, the triac TR1 is transmitted via the transistor Q1 with a predetermined delay time. A delay drive circuit 12 which is turned on to lead an AC input from the AC power supply 1 to the input capacitor C1 side without passing through the resistor R1.
Is provided.

The input control circuit 11 includes the first comparator IC3, the second comparator IC4, a first reference voltage source (reference voltage Vr) 13, and a second reference voltage source (reference voltage -Vr). 14, the inverting input terminal of the first comparator IC3 and the second comparator IC4.
Are connected in common to the output side of the resistor R1.

The non-inverting input terminal of the first comparator IC3 has a plus terminal of the first reference voltage source 13, and the inverting input terminal of the second comparator IC4 has a minus terminal of the second reference voltage source 14. Are connected, and the minus terminal of the first reference voltage source 13 and the second reference voltage source 1
The plus terminal of 4 is the three-terminal regulator IC1, I
Commonly connected to the connection point of C2.

The delay drive circuit 12 includes an input control circuit 1
1 is input to a non-inverting input terminal, and a voltage obtained by dividing a predetermined DC voltage VCC by resistors R6 and R7 is input to an inverting input terminal.
C5, a resistor R5 which drops a predetermined DC voltage VCC and supplies it to the inverting input terminal of the third comparator IC5,
And a capacitor C6 connected to the inverting input terminal of the comparator IC5 and the ground side of the resistor R7.

Further, the delay drive circuit 12 includes a timer integrated circuit IC6 having a trigger terminal connected to the output side of the third comparator IC5, and a timer integrated circuit IC6.
6 and an inverter IC7 connected through a resistor R12 between the output side of the transistor 6 and the base of the transistor Q1.

A predetermined DC voltage VCC is supplied to the timer integrated circuit IC6.
6 between the input terminal of the DC voltage VCC and the ground terminal.
9 Connects a series circuit of capacitor C7. further,
A resistor R8 is connected between the input terminal of the DC voltage VCC of the timer integrated circuit IC6 and the trigger input terminal, and a capacitor D7 is connected between the trigger input terminal and the ground.
Or connected.

Next, the operation of the power supply device having the above-described configuration will be described.
The operation at the time of the instantaneous power failure of the AC power supply 1 will be described as a seed and also with reference to FIG.

The power supply according to the first embodiment has an AC power supply 1
It is intended to prevent the rush current not only at the time of turning on the power, but also at the time of recovery from the instantaneous power failure.

That is, during normal operation of the power supply device, as shown in FIG. 2, when an input voltage (or input current) is supplied from the AC power supply 1, the input voltage is detected by the resistor R3. The signal is sent to the first comparator IC3 and the second comparator IC4.

The first comparator IC3 and the first comparator IC4 are connected to the input voltage and a predetermined reference voltage (V
r, -Vr) and outputs a low input transmission signal to the third comparator IC5 during normal operation.

As a result, the capacitor C6 is discharged, and the voltage of the capacitor C6 does not exceed the predetermined DC voltage Vcc divided by the resistors R6 and R7.

Accordingly, the output of the third comparator IC5 maintains a high level, the output of the timer integrated circuit IC6 is low, the output of the inverter IC7 goes high, and the base of the transistor Q1 is driven normally. ,
The transistor Q1 turns on and the triac T
The triac TR1 is turned on by driving the gate of R1, and the AC input from the AC power supply 1 is led to the rectifying and smoothing circuit via the triac TR1.

Next, it is assumed that an instantaneous power failure occurs in the power supply device according to the first embodiment. At this time, the resistor R3
When the input voltage is not detected by, as shown in FIG.
Since the capacitor C6 is charged via the resistor R5, the voltage continues to rise. The voltage across the capacitor C6 becomes equal to or higher than the voltage divided by the resistors R6 and R7, and the output of the third comparator IC5 is inverted to go low.

As a result, the trigger input terminal of the timer integrated circuit IC6 is triggered by the output inversion of the third comparator IC5. At this time, the diode D7
This prevents the charging current to the capacitor C7 flowing through the resistor R9.

The output of the inverter IC7 is inverted from the time when the timer integrated circuit IC6 is triggered to be low, whereby the transistor Q1 is turned off, and the gate of the triac TR1 is not driven, so that the triac TR1 is not driven. Is off.

Therefore, when the AC input from the AC power supply 1 is restored, the input voltage is supplied via the resistor R1.

When the input voltage is supplied, the input voltage is detected by the resistor R3, the capacitor C6 is discharged in the same manner as described above, and the third comparator IC
The output of 5 is inverted to high.

At this time, a trigger is applied to the timer integrated circuit IC6 by the output inversion of the third comparator IC5, but the output of the inverter IC7 has a constant value of the voltage of the capacitor C7 due to the delay operation of the timer integrated circuit IC6. The output is kept low for a predetermined delay time until the output becomes, and after the delay time has elapsed, the output is turned high.

As a result, the triac TR1 is kept off for a predetermined delay time and then turned on. Assuming that a predetermined delay time is Tcr, the delay time Tcr is equal to the resistance R9.
Tcr = 1.1 × r9 · c7, where r9 is the resistance of the capacitor and c7 is the capacitance of the capacitor C7.

As described above, even after the input voltage from the AC power supply 1 is recovered, the input current flows through the resistor R1 while the triac TR1 is off, so that the peak value of the input current is suppressed. Erroneous trip of the distribution system can be prevented.

Thereafter, after a predetermined delay time has elapsed, the input current flows stably via the triac TR1.

Embodiment 2 Embodiment 2 of the present invention will be described with reference to FIG.

In the second embodiment, components having the same functions as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The power supply device according to the second embodiment has basically the same configuration as that of the power supply device according to the first embodiment. However, the configuration of the DC voltage supply circuit includes a diode D5, a smoothing capacitor C2, The simplification of the configuration comprising the terminal regulator IC1 and the smoothing capacitor C4;
1, a second comparator IC4, a second reference voltage source (reference voltage -Vr) 14, and resistors R10 and R11.
And a parallel circuit of an input transmission cutoff element (thyristor) SCR1 and a resistor R1 which is an input current suppression element for suppressing an input current.
It is characterized in that a series circuit with the resistor R3 is connected to the subsequent stage of the rectifying and smoothing circuit.

The structure of the delay drive circuit 12 is the same as that of the first embodiment.
Is the same as In FIG. 3, R13 is a resistor connected between the base and the emitter of the transistor Q1.

In the power supply device according to the second embodiment, as in the first embodiment, the inrush current is prevented not only when the AC power is turned on, but also when an instantaneous power failure is restored.

In this power supply, if the input current (DC current) flowing through the resistor R3 is ip and the resistance values of the resistors R10 and R11 are r10 and r11, the second comparator I2
C4 is the input current ip and -vr.r11 / (r10.r3
) Value.

Here, during normal operation of this power supply,
As in the first embodiment, when the input current ip flows, the second
The output of the comparator IC4 goes low, discharging the electric charge of the capacitor C6.

Thus, the voltage of the capacitor C6 does not exceed the predetermined DC voltage Vcc divided by the resistors R6 and R7.

Accordingly, the output of the third comparator IC5 is maintained at a high level, the output of the timer integrated circuit IC6 is low, the transistor Q1 is turned on, and the gate of the input transmission cutoff element SCR1 is driven. The input transmission cutoff element SCR1 is turned on, and the input current is guided to the DC-DC converter 2 via the input transmission cutoff element SCR1.

Next, it is assumed that an instantaneous power failure occurs in the power supply according to the second embodiment. At this time, the resistor R3
When the input current ip is not detected, the voltage of the capacitor C6 is charged via the resistor R5 and the voltage continues to rise. The voltage across the capacitor C6 is equal to the resistance of the resistors R6 and R6.
7, the third comparator IC
The output of 5 is inverted and goes low.

As a result, the trigger input terminal of the timer integrated circuit IC6 is triggered by the output inversion of the third comparator IC5. At this time, the diode D7
This prevents the charging current to the capacitor C7 flowing through the resistor R9.

The output of the inverter IC7 is inverted from the time when the timer integrated circuit IC6 is triggered to be low, whereby the transistor Q1 is turned off and the gate of the input transmission cutoff element SCR1 is not driven. This input transmission cutoff element SCR1 is off.

Therefore, when the AC input from the AC power supply 1 is restored, the input voltage is supplied via the resistor R1.

When the input voltage is supplied, the input voltage is detected by the resistor R3, the capacitor C6 is discharged in the same manner as described above, and the third comparator IC
The output of 5 is inverted to high.

At this time, the timer integrated circuit IC6 is triggered by the output inversion of the third comparator IC5. However, the output of the inverter IC7 has a constant value of the voltage of the capacitor C7 due to the delay operation of the timer integrated circuit IC6. The output is kept low for a predetermined delay time until the output becomes, and after the delay time has elapsed, the output is turned high.

Thus, the input transmission cutoff element SCR1
Are kept on for a predetermined delay time and then driven on. Assuming that a predetermined delay time is Tcr, this delay time Tcr
Cr can be expressed by Tcr = 1.1 × r9 · c7, where r9 is the resistance value of the resistor R9 and c7 is the capacitance value of the capacitor C7.

In this way, even after the input voltage from the AC power supply 1 recovers, the input current flows via the resistor R1 while the input transmission cutoff element SCR1 is off.
The peak value of the input current is suppressed, and a power trip or the like can be prevented.

Thereafter, after a predetermined delay time has elapsed, the input current flows stably via the input transmission cutoff element SCR1.

[0062]

According to the first aspect of the present invention, there is provided a power supply device capable of preventing occurrence of an inrush current when power is turned on or returning after an instantaneous power failure has occurred, and which can exhibit stable operation. Can be provided.

According to the second aspect of the present invention, a parallel circuit of an input transmission cutoff element and an input suppression element is connected between the rectifying / smoothing circuit and the input capacitor. It is possible to provide a power supply device capable of preventing occurrence of an inrush current at the time of recovery and exhibiting stable operation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating waveforms of signals of respective units of the power supply device according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a power supply device according to an embodiment of the present invention.

FIG. 4 is a circuit diagram showing a conventional power supply device.

FIG. 5 is an explanatory diagram showing waveforms of signals of respective parts of a conventional power supply device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 AC power supply 2 DC / DC converter 11 Input control circuit 12 Delay drive circuit 13 First reference voltage source 14 Second reference voltage source IC3 First comparator IC4 Second comparator IC6 Timer integrated circuit IC7 Inverter R3 Resistance Q1 Transistor

Claims (2)

[Claims] 1. A power supply device for rectifying and smoothing an AC input from an AC power supply, converting the DC input into a DC voltage by a switching power supply circuit having an input capacitor, and outputting the DC voltage, wherein the power supply device is connected between the AC power supply and the input capacitor. on,
Transmission of input from AC power supply by driving off,
An input transmission cutoff element that performs cutoff, a parallel circuit of an input suppression element that suppresses input current, an input transmission cutoff element drive circuit that turns on and off the input transmission cutoff element, the AC power supply, and an input capacitor. An input detection circuit for detecting the presence or absence of an input from the AC power supply connected in series with the parallel circuit, and comparing an input voltage detected by the input detection circuit with a predetermined reference voltage to determine an input voltage. An input control circuit that outputs an input transmission signal when the input transmission signal changes from a state in which no input signal is detected to a state exceeding a predetermined reference voltage, based on the input transmission signal from the input control circuit, with a predetermined delay time to interrupt the input transmission signal A delay for turning on the input transmission cutoff element through an element drive circuit and leading an AC input from an AC power supply to the input capacitor side without passing through the input suppression element; A power supply device comprising: a driving circuit; 2. A power supply device for rectifying and smoothing an AC input from an AC power supply by a rectifying / smoothing circuit, and converting the input into a DC voltage by a switching power supply circuit having an input capacitor and outputting the DC voltage. A parallel circuit of an input transmission cutoff element for transmitting and blocking an input from an AC power supply by being turned on and off, and an input suppression element for suppressing an input current, the input transmission cutoff element An input transmission cut-off element driving circuit for driving on and off; an input detection circuit for detecting the presence or absence of an input from the AC power supply connected in series with the parallel circuit between the rectifying and smoothing circuit and an input capacitor; The input voltage detected by the detection circuit is compared with a predetermined reference voltage, and when the input voltage is not detected, the predetermined reference voltage is output. An input control circuit that outputs an input transmission signal at the time when the input transmission circuit changes to an input state, and based on the input transmission signal from the input control circuit, interrupts the input transmission via the input transmission interruption element driving circuit with a predetermined delay time. And a delay drive circuit for turning on the element and guiding the DC voltage input from the AC power supply and output from the rectifying / smoothing circuit to the input capacitor without passing through the input suppression element.