JP2000188863A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device which achieves the reduction of power consumption by a method, wherein a secondary side DC voltage is turned off when a power supply switch is turned off. SOLUTION: When a power supply switch SW1 connected to a primary side is turned off, a turn-off signal is transmitted to a secondary side via a photocoupler PC1, and after the initialization processing of a device is finished through a sequence circuit 8, the signal is fed back to the primary side via a photocoupler PC2 and a control IC IC1 is turned off to stop the operation of a switching transistor Q2. If the signal does not change for a prescribed time, a signal is transmitted to the sequence circuit 8 from a power saving circuit 9, and after the initialization process of the device is finished, transistors Q5 and Q6 are turned off to cause an output voltage V2 to turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device,
In particular, the present invention relates to a power supply device using a switching regulator.

[0002]

2. Description of the Related Art As shown in FIG.
A power switch SW1 connected between the resistor R6 connected to the logic voltage V1 and the ground;
A sequence circuit 108 in which the input Vin is connected to the resistor R6 side of W1, and an output Vou of the sequence circuit 108
It comprises a transistor Q5 whose base is connected to t, and a transistor Q6 whose base is connected to the collector of this transistor Q5 to turn on / off the DC voltage V2 on the secondary side of the transformer 4.

As shown in FIG. 2, the operation of this conventional power supply device is to operate the sequence circuit 108 when the power switch SW1 is off, that is, when the input is at the HIGH level.
After the device initialization process is completed, the sequence circuit 1
By turning off the output of the transistor 08 and turning off the transistor Q6 by turning off the transistor Q5, the control to turn off the DC voltage V2 on the secondary side of the transformer 4 is performed.

[0004]

However, the conventional power supply device only turns off the DC voltage on the secondary side of the transformer when the power supply switch is turned off. Even when the power supply switch is turned off, the control IC on the primary side of the transformer is not used. Has a problem that wasteful power is consumed because the operation is continued and the switching operation is continued.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply device that realizes low power consumption by turning off a DC voltage on the secondary side of a transformer when a power switch is turned off.

[0006]

In order to solve the above-mentioned problems, a power supply device of the present invention comprises a rectifying and smoothing means for rectifying and smoothing an input AC power supply, and a rectifying and smoothing means for rectifying and smoothing the AC power. A switching transistor for switching an AC power supply, and a rectified and smoothed AC power supply switched by the switching transistor is input to a primary winding to output an output voltage to a secondary winding, and is controlled to a tertiary winding. Transformer that generates voltage and 3 of this transformer
First control means for controlling the switching transistor via a control IC by a control voltage generated in the secondary winding, DC generation means for rectifying and smoothing the output voltage sent to the secondary winding, and the transformer First detecting means for detecting the on / off state of the power switch on the primary side and transmitting a detection signal, and a first transmission for transmitting the detection signal transmitted from the first detecting means to the secondary side of the transformer Means, a detection signal transmitted to the first transmission means, a sequence circuit for controlling initialization processing of a device serving as a load on the DC generation means, and a detection signal detected by detecting the initialization processing by the sequence circuit. A second detecting means for transmitting, a second transmitting means for transmitting a detection signal from the second detecting means to the primary side, and the power switch based on the detecting signal transmitted by the second transmitting means. Only when it is off, the control I
A second control means for turning off the operation of C; and a power saving circuit for sending an output signal to the sequence circuit when there is no input signal for a predetermined time, and controlling the DC voltage to be turned off after initialization processing. It is characterized by having been done.

[0007]

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

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

A power supply according to an embodiment of the present invention comprises:
As shown in FIG. 1, a rectifying and smoothing means 2 for rectifying and smoothing an input AC power supply 1 by an input diode D1 and an input capacitor C1, and a switching transistor for switching the AC power supply 1 rectified and smoothed by the rectifying and smoothing means 2. Q1 and the rectified and smoothed AC power supply 1 switched by the switching transistor Q1 are input to the primary winding 41 and output voltages V1,
A transformer 4 for transmitting V2 and generating a control voltage in the tertiary winding 44, and a first control for controlling the switching transistor Q1 via the control ICIC1 by the control voltage generated in the tertiary winding 44 of the transformer 4. Control means 31 and 2
DC generation means 51, 52 for rectifying and smoothing the output voltage sent to the next windings 42, 43 by output diodes D3, D4 and output capacitors C3, C4; A first detecting means 61 for detecting an OFF state and transmitting a detection signal;
The first transmission means 71 transmits the detection signal sent from the first transmission means 1 to the secondary side of the transformer 4, and the detection signal transmitted to the first transmission means 71 allows the DC generation means 51, 52 A sequence circuit 8 for controlling the initialization processing, a second detection means 62 for detecting the initialization processing by the sequence circuit 8 and sending out a detection signal, and a detection signal from the second detection means 62 is sent to the primary side. Only when the power switch SW1 is turned off by the second transmitting means 72 for transmitting and the detection signal transmitted by the second transmitting means 72,
Second control means 32 for turning off the operation of control IC IC1
And a power save circuit 9 for sending an output signal to the sequence circuit 8 when there is no input signal for a predetermined time, and controlling the DC voltage V2 to be turned off by the transistors Q5 and Q6 after the initialization processing.

Further, the first control means 31 includes a control ICIC for controlling on / off of the switching transistor Q1.
1 and the AC power supply 1 smoothed by the input capacitor C1 are charged through the starting resistor R1 and
A starting capacitor C2 for smoothing the control voltage generated by the secondary winding 44, a photocoupler PC3 for receiving a ground signal from the control ICIC1 when the AC power supply 1 is input, and an output voltage V1 generated by the DC generation means 51 are connected to resistors R7 and R7. A second control means including a reference voltage ICIC2 biased by R8, a photocoupler PC3 for detecting and emitting light via a resistor R9, and a starting diode D2 for rectifying a control voltage generated by a tertiary winding 44 of a transformer 4. Is the starting voltage Vcc
ICIC1 biased by resistors R3 and R4
, A light-receiving-side photocoupler PC2, and a transistor Q2 that is turned on / off by turning on / off the power switch SW1.

Further, the first detecting means 61 includes a power switch SW1 connected in series to the AC power supply 1 rectified and smoothed by the rectifying / smoothing means 2 through a resistor R2, and a light emission for detecting on / off of the power switch SW1. Side photo coupler P
C2 and a resistor R5 connected in series to the light-emitting side photocoupler PC1. The second detection means 62 includes a transistor Q4 that is turned on / off by a signal from the output Vout of the sequence circuit 8, and an on / off state of the transistor Q4. And a light-emitting side photocoupler PC2 for detecting ON / OFF.

Alternatively, the first transmitting means 71 is formed by a light receiving side photocoupler PC1 connected in series to the output voltage V1 generated by the DC generating means 51 via a resistor R6.
The second transmission unit 72 is configured by a light receiving side photocoupler PC2 that transmits the signal detected by the second detection unit 62 to the primary side.

Next, the operation of the power supply according to one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the operation of the power supply device according to one embodiment of the present invention is such that when the power switch SW1 connected to the primary side is turned off, the light-emitting side photocoupler PC1 is turned on.
Is stopped, the transistor Q2 biased by the resistor R5 is turned off, the signal is not transmitted to the light receiving side photocoupler PC1, the light receiving side photocoupler PC1 is turned off, and the collector terminal of the light receiving side photocoupler PC1 is turned off. HI
GH level.

Thereafter, the input Vin1 of the sequence circuit 8
Also becomes HIGH level and the sequence circuit 8 operates,
When the initialization process of the device is completed, the output Vout of the sequence circuit 8 becomes LOW level, the transistor Q4 is turned off, and the light emission side photocoupler PC2 connected to the logic voltage V1 stops emitting light.

When the output Vout of the sequence circuit 8 goes low, the transistor Q5 is also turned off, the transistor Q6 is turned off, and the output of the output voltage V2 is turned off. The transmission of the signal to the light receiving side photocoupler PC2 on the next side is also stopped, and the light receiving side photocoupler PC2 is turned off and the transistor Q2 is turned off, so that the starting voltage Vcc is turned on by the voltage biased by the resistors R3 and R4. Then, the ON / OFF terminal voltage of the control ICIC1 becomes LOW level, and the operation of the control ICIC1 is stopped.

The control ICIC1 has an ON / OFF terminal which is turned on when HIGH and turned off when LOW.
Is stopped, the operation of the switching transistor Q1 is also stopped, the power switch SW1 connected to the primary side is turned on, the light-emitting side photocoupler PC1 detects and emits light, and a bias voltage is applied to the resistor R5 to apply a bias voltage to the transistor. When Q2 is turned on, the base and the emitter of the transistor Q3 are short-circuited, the transistor Q3 is turned off, the control ICIC1 is turned on and the switching transistor Q1 starts operating, and the secondary winding is passed through the primary winding 41 of the transformer 4. Voltages are generated in the DC generation means 51 and 42.
Is output and transmitted to the light receiving side photocoupler PC1 via the light emitting side photocoupler PC1.

Further, the signal transmitted from the light receiving side photocoupler PC1 turns on the light receiving side photocoupler PC1.
When the collector terminal of the light-receiving-side photocoupler PC1 goes low and the input Vin1 of the sequence circuit 8 goes low / the output Vout goes high, the transistor Q4 turns on and the light-emitting side photocoupler PC2 detects and emits light. A signal is transmitted to the light receiving side photocoupler PC2 on the next side, and the light receiving side photocoupler PC2 on the primary side is turned on. However, the operation does not change because the transistor Q2 is turned on first, and the transistor Q4 is turned on. At the same time, the transistor Q5 is turned on, and the transistor Q6 is also turned on to output the output voltage V2.

Therefore, if the signal does not change for a predetermined time,
From the power save circuit 9, the input Vi of the sequence circuit 8
When a signal is input to n2 and the sequence circuit 8 completes device initialization processing and completes, when the output Vout of the sequence circuit 8 becomes LOW level, the transistor Q
5 and the transistor Q6 are turned off to turn off the output of the output voltage V2, and when the output Vout of the sequence circuit 8 becomes LOW level, the transistor Q4 is turned off and the output voltage V
Even if the light emission side photocoupler PC2 connected to 1 stops emitting light and the primary light reception side photocoupler PC2 is turned off, the operation is not affected because the transistor Q2 is on.

[0020]

As described above, according to the power supply device of the present invention, when the power switch connected to the primary side is turned off, a signal is transmitted to the secondary side via the photocoupler and the sequence is performed. After the device is initialized through the circuit, the signal is fed back to the primary side via the photocoupler,
The control IC is turned off to stop the operation of the switching transistor. If there is no change in the signal for a predetermined time, a signal is sent from the power save circuit to the sequence circuit, and the output voltage is turned off after the completion of the device initialization processing. This has the effect of realizing low power consumption.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 AC power supply 2 Rectifying and smoothing means 31 First control means 32 Second control means 4 Transformers 51, 52 DC generation means 61 First detection means 62 Second detection means 71 First transmission means 72 Second transmission means 8 Sequence circuit 9 Power Save circuit 41 Primary winding 42, 43 Secondary winding 44 Tertiary winding C1 Input capacitor C2 Starting capacitor C3, C4 Output capacitor D1 Input diode D2 Starting diode D3, D4 Output diode IC1 Control IC IC2 Reference voltage IC Q1 Switching Transistor Q2, Q3, Q4, Q5, Q6 Transistor R1 Start-up resistance R2-R9 Resistance PC1-PC3 Photocoupler

Claims (1)

[Claims] 1. A rectifying and smoothing means for rectifying and smoothing an input AC power supply, a switching transistor for switching the AC power supply rectified and smoothed by the rectifying and smoothing means, and a rectification and smoothing switched by the switching transistor. A transformer that inputs the AC power to the primary winding, sends an output voltage to the secondary winding, and generates a control voltage in the tertiary winding, and a control voltage generated in the tertiary winding of the transformer. First control means for controlling the switching transistor via a control IC, DC generation means for rectifying and smoothing the output voltage sent to the secondary winding, and turning on a power switch on the primary side of the transformer. A first detecting means for detecting the detection signal / off and transmitting a detection signal; and a second detecting means for transmitting the detection signal transmitted from the first detecting means to the secondary side of the transformer. (1) a transmission circuit, a sequence circuit for controlling an initialization process of a device serving as a load of the DC generation unit based on the detection signal transmitted to the first transmission device, and an initialization process performed by the sequence circuit; A second detector for transmitting a signal, a second transmitter for transmitting a detection signal from the second detector to the primary side, and the power switch is turned off by the detection signal transmitted by the second transmitter. Second control means for turning off the operation of the control IC only when the input signal is ON, and sending an output signal to the sequence circuit when there is no input signal for a predetermined time, and controlling to turn off the DC voltage after initialization processing. And a power saving circuit.