JP2003169467A - Operation-control apparatus and switching power-supply unit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the degree of freedom in circuit design and the application range of control output in a switching power-supply unit 11 where an operation control circuit 15 sets the operation of a main output circuit 13 to be in an on-state, a continuous state, and an off-state when an input control signal to a terminal CTR is set to a high level, an open state, and a low level, respectively. <P>SOLUTION: A photothyristor 17 is used for the operation control circuit 15, a diode 17a is driven by the input control signal, and a control output to the main output circuit 13 is led by a thyristor 17b. Therefore, since a gate and a cathode need to be short-circuited to reduce the current between an anode and a cathode to a retention current or lower for turning off a normal thyristor, the cathode to be grounded is set to be the photothyristor 17 for use in a floating state, thus increasing the degree of freedom in circuit design and the application range of control output. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the operation of an electronic device in order to reduce the power consumption of the device when the device is on standby. The present invention relates to a switching power supply device.

[0002]

2. Description of the Related Art Conventional switching power supplies are designed to have maximum efficiency at the rated load, and no measures have been taken for the efficiency with respect to the minimum load and the load during standby. However, in recent years, CO ₂ emission regulations have been called out as a measure against global warming, and especially for electronic devices that are always connected to a power supply, it is an urgent task to reduce the power consumption during standby, which has a large proportion. There is.

Therefore, as a method for reducing the power consumption in the standby mode, a structure of a plurality of power sources in which an independent switching power source dedicated to the standby mode is provided in addition to the main power source, and the single power source is often used. A configuration of a power supply having a system output can be considered. However, the configuration of the multiple power sources is not preferable in terms of mounting area, cost, etc. Therefore, it is desired to use the multi-system output power source.

In the multi-system output power supply, a stabilized output created by a series regulator from the output voltage of the main winding is derived from the standby sub-output, and the switching output is used as a commercial power supply for the sub-output. It is continuously output while connected, and supplies power to the control unit of the load side device. On the other hand, to the main output, a stabilized output created by the main series regulator is derived from the output voltage of the main winding, and in order to reduce the power consumption during the standby, the load side device is reduced. ON / OFF control is performed by a control signal from the control unit. That is, when the ON signal is received from the control unit of the load side device, the main output is turned ON to enter the normal operation state, and when the OFF signal is received, the main output is turned OFF to enter the standby state.

Regarding the handling of the control signal,
Main output is O at High level (5Vor3.3V)
A design such that the main output is kept ON in the open state from the N and High levels and the main output is turned OFF at the Low level (0 Vor GND ground) is often used in power supplies related to OA equipment such as printers. Conventionally, in order to realize such an operation, a switching power supply device 1 as shown in FIG. 7 is used.

This switching power supply device 1 generally has a main switching MOSFET q1 and a PWM control IC.
Primary circuit such as 2 and the like, transformer n, and main output circuit 3
A sub output circuit 4 and an operation control circuit 5 for the main output circuit 3.

The output voltage of the DC power source b after AC rectification and smoothing is smoothed by the primary electrolytic capacitor c1 and given to the series circuit of the primary winding n1 of the transformer n and the main switching MOSFET q1. The main switching MOSF
ETq1 is a PWM control I via a bias resistor r1.
ON / OFF control is performed by the output from the terminal OUT of C2. The PWM control IC 2 is, for example, an F manufactured by Fuji Electric.
It can be realized with A5311, and details of its operation are as follows.
Since it is described in the application note of the IC of Fuji Electric, the details are omitted and the general operation is described below.

The voltage induced in the secondary winding n2 of the transformer n by the switching of the main switching MOSFET q1 is rectified and smoothed by the diode d1 and the secondary electrolytic capacitor c2 in the main output circuit 3, and then output. It is derived as a main output to the load side device via the control MOSFET q2.
The main output is divided by resistors r2 and r3 and input to the reference terminal R of the shunt regulator 6.
The shunt regulator 6 is interposed in series between the main output lines together with the photodiode d2 of the photocoupler pc and the resistor r4. A bias resistor r5 is provided in parallel with the photodiode d2.

The shunt regulator 6 compares the voltage divided by the resistors r2 and r3 of the main output voltage with an internal reference voltage to determine the impedance between the anode and the cathode. Therefore, the value of the current flowing through the photodiode d2 of the photocoupler pc changes according to the voltage of the main output, and is fed back from the phototransistor tr1 of the photocoupler pc to the feedback terminal FB of the PWM control IC2. The PWM control IC2
The terminal RT of is a terminal that determines the oscillation frequency, and is connected to GND via the resistor r6. Therefore, P
The WM control IC 2 internally creates a triangular wave having an oscillation frequency corresponding to the resistor r6, and slices the triangular wave with the voltage of the feedback terminal FB to determine the switching duty of the main switching MOSFET q, thus The voltage of the main output is kept constant.

Power supply input terminal VC of the PWM control IC 2
In C, the voltage generated in the auxiliary winding n3 of the transformer n is
It is input after being rectified and smoothed by the diode d3 and the electrolytic capacitor c3.

On the other hand, a part of the voltage generated in the secondary winding n2 is stabilized by a sub output circuit 4 realized by a dropper type series regulator or the like, and then, as a sub output serving as a standby power source, It is supplied to the control unit of the load side device. On the other hand, a control signal indicating whether the load side device is in the normal operation state or in the standby state is input from the control unit to the terminal CTR of the operation control circuit 5 and responds to the control signal. Then, the operation of the main output circuit 3 is controlled.

The operation control circuit 5 includes a thyristor 7 to which the control signal is applied to its gate and a bias resistance r thereof.
7, a setting resistor r8 for giving an output voltage from the series regulator 4 to the anode of the thyristor 7, a transistor tr2 controlled by the terminal voltage of the anode of the thyristor 7, and an output voltage from the sub output circuit 4. It is provided with series resistors r9 and r10 provided. The transistor tr2 is connected to the connection point of the series resistors r9 and r10, and the connection point serves as an output terminal to drive the base of the transistor tr3 of the main output circuit 3.

The collector of the transistor tr3 is connected to the gate of the output controlling MOSFET q2 via the resistor r11, and the gate of the MOSFET q2 is connected to the gate of the MOSFET q2.
A bias resistor r12 is provided between the sources.

Therefore, when the terminal CTR is at the high level, the gate of the thyristor 7 is at the high level, the thyristor 7 is turned on, and the base of the transistor tr2 is turned to the low level and turned off, so that the transistor tr3 is on standby. Voltage to the series resistance r9,
The voltage divided by r10 enters the base and is turned on. Therefore, MOSFET q2 is turned on and the main output is turned on. On the other hand, if the terminal CTR is opened from that state, the thyristor 7 continues to be in the ON state.
The SFETq2 is also turned on, and the main output remains on.

On the other hand, when the terminal CTR becomes low level, the holding current of the thyristor 7 becomes large, so that the thyristor 7 cannot be maintained in the ON state and becomes OFF.
Therefore, the base of the transistor tr2 becomes High level and is turned ON, and therefore the base of the transistor tr3 is short-circuited and turned OFF, so that the MOSFET q2 is opened and the main output does not appear. When the terminal CTR is opened from this state, the thyristor 7 remains in the OFF state, so that the MOSFET q2 is also turned off.
And the main output remains off.

[0016]

In the switching power supply device 1 configured as described above, the main output is turned on and off at the High level in response to the control signal to the terminal CTR.
Keeps ON in the open state from the high level, Low
The thyristor 7 is used in order to realize the above-described operation that is turned off at the level. The thyristor is turned on when a voltage is applied to the gate, and in order to be turned off, the gate voltage must be turned off and the current between the anode and the cathode must be equal to or less than the holding current.

However, in this switching power supply device 1, the gate and cathode of the thyristor 7 are short-circuited,
The OFF operation is realized by increasing the holding current. Therefore, the large holding current varies due to variations in temperature and thyristor 7, and in order to ensure reliable operation, the bias resistor r7 and the setting resistor r8 are
There is a problem that a constant must be set in consideration of the variation.

Further, in order to obtain a large holding current as described above, the cathode of the thyristor 7 must be connected to GND, so that the control output from the anode can be changed by changing the oscillation frequency or the output voltage. There is a problem that it is difficult to use for operation.

An object of the present invention is to provide an operation control device and a switching power supply device using the operation control device which can expand the degree of freedom in circuit design and the applicable range.

[0020]

In the operation control device of the present invention, the input control signal indicates the operating state of the controlled circuit.
In an operation control device configured to turn on at an h level, maintain at an open state, and turn off at a low level, a photothyristor is provided, and a diode of the photothyristor is driven by the input control signal. It is characterized in that the control output to the control circuit is derived.

According to the above construction, the standby (sub) output which is always output and the ON / OFF control by the input control signal
The above-described operation is realized in an operation control device, such as a power supply device having a main output to be controlled, whose operation state is such that the input control signal is ON at the High level, maintained in the open state, and turned OFF at the Low level. The thyristor is a photothyristor, the diode of the photothyristor is driven by the input control signal, and the control output to the controlled circuit is derived by the thyristor of the photothyristor.

Therefore, it is turned off in a normal thyristor.
Since it is necessary to short-circuit the gate-cathode in order to make the current between the anode and the cathode less than the holding current, the grounded cathode can be used in a floating state by using the photothyristor. . As a result, the influence of variations in temperature and thyristor is reduced, the redundancy of the controlled circuit for the input is increased, the degree of freedom in circuit design is expanded, and the design can be facilitated. Further, since the thyristor of the photothyristor can arbitrarily take the potential on the cathode side, this control output can be used also for the control of circuits other than the controlled circuit, and the application range can be expanded.

Further, the switching power supply device of the present invention is
The operation control device as the operation control circuit, wherein the controlled circuit is a main output circuit, power is supplied from a sub output circuit which is a standby power supply, and ON / OFF control of the main output circuit is performed in response to the input control signal. Is used.

According to the above configuration, the switching power supply device can be easily designed, and other control such as changing the oscillation frequency or changing the setting of the output voltage can be performed by the common operation control circuit. Can be realized.

Furthermore, in the switching power supply device of the present invention, the operation control circuit is interposed between the power supply lines from the sub output circuit which is the standby power supply, and the diode 17a of the photothyristor, the resistor R7, and the input. A series circuit including a transistor TR2 to which a control signal is applied to the base and a Zener diode D3 for adjusting the ON voltage of the transistor TR2, a transistor TR3 for connecting the anode of the thyristor 17b of the photothyristor to the standby power supply, and a resistor R8. A bias resistor R9 connecting the base and emitter of the transistor TR3 and the base of the transistor TR3 to GND.
A resistor R10 connected to the transistor TR4, a pull-up resistor R11 connecting the base of the transistor TR4 to the standby power supply, and the transistor TR4.
And a diode D4 for supplying the input control signal to the base of the above, and the control output is derived from the cathode of the thyristor 17b to the main output circuit.

According to the above configuration, when the high level control signal is input, the transistor TR2 is turned on,
Photocurrent flows through the diode 17a of the photothyristor,
The thyristor 17b turns on. Further, the voltage of the standby power supply is applied to the base of the transistor TR4 via the pull-up resistor R11, the diode D4 is turned off, and the transistor TR4 is turned on. Therefore, when the thyristor 17b is turned on, the transistor TR3 is turned on, a voltage is applied to the main output circuit, and the main output circuit is turned on.

When the control signal is opened in this state, the transistor TR2 is turned off and the photocurrent of the diode 17a of the photothyristor stops flowing. However, since the transistor TR4 continues to be turned on, the transistor TR3 is turned on, and therefore the holding current is secured in the thyristor 17b, so that the thyristor 17b is turned on.
Maintain N. Therefore, the main output circuit remains ON.

On the other hand, when a low level control signal is input, the transistor TR2 is turned off and the photocurrent of the diode 17a of the photothyristor also stops flowing. Further, since the diode D4 is turned on, the transistor TR4 is turned off. This allows the thyristor 17
The current flowing in b disappears and the thyristor 17b becomes OF
F, the voltage is not applied to the main output circuit, and the main output circuit is turned off. When the control signal is opened in this state, the diode 17 of the photothyristor is opened.
Since a and the thyristor 17b are kept off, the main output circuit is kept off.

Therefore, the above-described operation of turning on the operation state of the main output circuit when the input control signal is High level, continuing in the open state, and turning off when the input control signal is Low level is performed by the simple operation of the photothyristor, the transistor, the diode and the like. It can be realized by a circuit.

In the switching power supply device of the present invention, the main output circuit further includes a resistor R21 in series with the voltage dividing resistors R2 and R3 for feedback of the output voltage to the primary side, and the resistor R21. And a transistor TR21 connected in parallel with the transistor TR21, and a control output from the operation control circuit is given to the base of the transistor TR21.

According to the above configuration, when the input control signal becomes High level or becomes open from the High level, the transistor TR21 is also turned on by the control output from the operation control circuit, and the terminals of the resistor R21 are short-circuited. As a result, the divided voltage value of the voltage of the main output becomes smaller, which increases the switching duty and raises the voltage of the main output.

On the other hand, when the input control signal is Low
When the level or the Low level is opened, the transistor TR21 is turned off and the resistor R2 is turned on.
1 is inserted, the divided voltage value of the main output increases, and the duty of switching decreases accordingly, and the voltage of the main output decreases.

Therefore, during standby, the voltage applied to the secondary side circuit drops, and the power consumption can be further reduced.

Furthermore, in the switching power supply device of the present invention, in the control circuit for controlling the switching on the primary side, the resistor R3 for setting the oscillation frequency is connected in parallel with the resistor R3.
1, a phototransistor TR31 of the photocoupler PC2 is provided in series with the resistor R31, and the operation control circuit further includes a photodiode D31 of the photocoupler PC2 in series with the thyristor 17b.
Is provided.

According to the above configuration, when the input control signal is at the high level or is opened from the high level and the main output circuit is turned on, the phototransistor TR31 is turned on, and the resistor R31 is connected in parallel with the resistor R6. Is inserted, the resistance value decreases and the switching frequency increases. On the other hand, when the input control signal is at the low level or is opened from the low level and the main output circuit is turned off, the phototransistor TR31 is turned off, the resistor R31 is not inserted, and the oscillation frequency becomes low.

Therefore, the switching frequency during standby can be set separately from the switching frequency determined by the power to be supplied to the load side device when the main output is turned on, and the power consumption during standby can be further reduced. be able to.

Further, the switching power supply device of the present invention is
The secondary side of the transformer has another winding, and the operation state of the output circuit of the winding is also controlled by the operation control circuit.

According to the above configuration, it is possible to turn off the unnecessary output from the separate winding during standby and reduce the power consumption.

Furthermore, the switching power supply device of the present invention is characterized in that a charge extracting circuit is provided at the subsequent stage of the main output circuit, and the operation state thereof is also controlled by the operation control circuit.

According to the above configuration, the main output circuit is O
When it becomes FF, the charge extracting circuit operates, the charge of the main output can be quickly extracted, and the output voltage can be rapidly reduced.

Further, the switching power supply device of the present invention is
The secondary side of the transformer has a separate winding, and one of the output circuit of the winding and the main output circuit is supplied with the control output from the operation control circuit, and the other is controlled by the control output from one. It is characterized by

According to the above construction, it is possible to provide a time difference in the operation timing between the load of the separate winding and the load of the main output.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing an electrical configuration of a switching power supply device 11 according to the first embodiment of the present invention.

The switching power supply device 11 generally includes a main switching MOSFET Q1 and a PWM control IC.
12, a primary side circuit, a transformer N, a main output circuit 13, a sub output circuit 14, the main output circuit 13
And the operation control circuit 15 of FIG.

The output voltage of the DC power source B after AC rectification and smoothing is smoothed by the primary electrolytic capacitor C1 and given to the series circuit of the primary winding N1 of the transformer N and the main switching MOSFET Q1. The main switching MOSF
ETQ1 is PWM control I via bias resistor R1.
ON / OFF control is performed by the output from the terminal OUT of C12. The PWM control IC 12 can be realized by, for example, FA5311 manufactured by Fuji Electric.

The voltage induced in the secondary winding N2 of the transformer N by the switching of the main switching MOSFET Q1 is rectified by the diode D1 and the secondary electrolytic capacitor C2 in the main output circuit 13.
After being smoothed, it is derived as a main output to the load side device via the output control MOSFET Q2.
The main output is divided by resistors R2 and R3 and input to the reference terminal R of the shunt regulator 16. The shunt regulator 16 includes a photo coupler P.
With the photodiode D2 of C1 and the resistor R4,
The main output lines are interposed in series. A bias resistor R5 is provided in parallel with the photodiode D2.

The shunt regulator 16 compares the voltage division value of the main output voltage by the resistors R2 and R3 with an internal reference voltage to determine the impedance between the anode and the cathode. Therefore, the value of the current flowing through the photodiode D2 of the photocoupler PC1 changes according to the voltage of the main output, and is fed back from the phototransistor TR1 of the photocoupler PC1 to the feedback terminal FB of the PWM control IC 12. The terminal RT of the PWM control IC 12 is a terminal that determines the oscillation frequency, and is connected to GND via the resistor R6. Therefore, the PWM control IC 12 determines a switching duty of the main switching MOSFET Q by internally creating a triangular wave having an oscillation frequency corresponding to the resistor R6 and slicing the triangular wave with the voltage of the feedback terminal FB, Thus, the voltage of the main output is kept constant.

Power supply input terminal V of the PWM control IC 12
The voltage generated in the auxiliary winding N3 of the transformer N is rectified and smoothed by the diode D5 and the electrolytic capacitor C3, and then input to CC.

On the other hand, a part of the voltage generated in the secondary winding N2 is stabilized by a sub output circuit 14 realized by a dropper type series regulator or the like, and then, as a sub output serving as a standby power source, It is supplied to the control unit of the load side device. On the other hand, from the control unit to the operation control circuit 15
A control signal indicating whether the load side device is in a normal operating state or in a standby state is input to the terminal CTR of, and the operation of the main output circuit 13 is controlled in response to the control signal. .

The above-mentioned configurations of the primary side control section and the secondary side main voltage setting section are the same as those of the switching power supply device 1 shown in FIG. It should be noted that in the present invention, the operation control circuit 15 uses a photothyristor 17 instead of the thyristor 7. The operation control circuit 15 includes the photothyristor 17, transistors TR2 to TR4, and resistors R7 to R11.

A series circuit of a diode 17a of the photothyristor 17, a resistor R7, a transistor TR2 and a zener diode D3 is interposed between the power supply lines from the sub output circuit 14 which is a standby power supply, and the transistor TR2 is provided. The control signal is applied to the base of the. The Zener diode D3 has the H level of the control signal.
Turning on the transistor TR2 for high level voltage
It is provided for adjusting the voltage. In the thyristor 17b of the photothyristor 17, the anode is the transistor T
It is connected to the standby power supply through R3 and the resistor R8, and the cathode is connected to the base of the transistor TR5 of the main output circuit 13.

The collector of the transistor TR5 is connected to the gate of the output controlling MOSFET Q2 via the resistor R12, and the gate of the MOSFET Q2 is
A bias resistor R13 is provided between the sources.

The base and emitter of the transistor TR3 are connected by a bias resistor R9, and the transistor T3
The base of R3 is composed of a resistor R10 and a transistor TR4.
It is connected to GND through. The transistor T
The base of R4 is connected to the standby power supply by a pull-up resistor R11, and a diode D4 is further provided.
From the anode through the cathode to the terminal CTR.

The operation control circuit 15 configured as described above.
When a high level control signal is input to the terminal CTR, the transistor TR2 is turned on, a photocurrent flows through the diode 17a of the photothyristor 17, and the thyristor 17b is turned on. Further, the voltage of the standby power supply is applied to the base of the transistor TR4 via the pull-up resistor R11, the diode D4 is turned off, and the transistor TR4 is turned on. Therefore, when the thyristor 17b is turned on, the transistor TR3 becomes O.
Then, a voltage is applied to the base of the transistor TR5 through the resistor R8, the transistor TR3 and the thyristor 17b, the transistor TR5 is turned on, and the MOSFE is turned on.
TQ2 also turns on. This causes the main output to go to terminal M.
It is output to AIN and supplied to the load side device.

When the terminal CTR is opened in this state, the transistor TR2 is turned off and the photocurrent of the diode 17a of the photothyristor 17 stops flowing. However, since the transistor TR4 continues to be turned on, the transistor TR3 is turned on, and therefore the holding current is secured in the thyristor 17b.
7b remains ON. Therefore, the transistor TR
5 and MOSFET Q2 also turn on, main output turns on
To maintain.

On the other hand, when a low level control signal is input to the terminal CTR, the transistor TR2 is turned off and the photocurrent of the diode 17a of the photothyristor 17 also stops flowing. Further, since the diode D4 is turned on, the transistor TR4 is turned off. As a result, the current flowing through the thyristor 17b disappears, the thyristor 17b turns off, the transistor TR5 and the MOSFET Q2 turn off, and the main output turns off.

When the terminal CTR is opened in this state, the diode 17a and the thyristor 17b of the photothyristor 17 are kept off, so that the transistor TR5 and the MOSFET Q2 are also kept off and the main output is kept off.

As described above, in the switching power supply device 1 having the standby sub output circuit 14 which always outputs and the main output circuit 13 which is ON / OFF controlled by the input control signal, the operation control circuit 15 of the present invention is In order to realize an operation in which the input control signal is turned on at a high level, maintained at an open state, and turned off at a low level, a thyristor for realizing such an operation is called a photothyristor 17, and the photothyristor is controlled by the input control signal. The diode 17a is driven, and the control output to the main output circuit 13 is derived by the thyristor 17b.

Therefore, in a normal thyristor, it is turned off.
In order to make the current between the anode and the cathode equal to or less than the holding current, it is necessary to short-circuit the gate and the cathode. Therefore, the cathode that is grounded can be used in the floating state by using the photothyristor 17. it can. As a result, the influence of variations in temperature and thyristor is reduced, the redundancy for the input of the main output circuit 13 is increased, the degree of freedom in circuit design is expanded, and the design can be easily performed.

Further, the operation state of the main output circuit 13 is
The above-described operation of turning on the input control signal at the high level, maintaining the open state, and turning off at the low level is performed by the photothyristor 17 and the transistors TR2 to TR.
4 and the diodes D3 and D4.

FIG. 2 shows the second embodiment of the present invention.
The explanation is based on the following.

FIG. 2 is a block diagram showing an electrical configuration of the switching power supply device 21 according to the second embodiment of the present invention. This switching power supply device 21 is similar to the switching power supply device 11 described above, and corresponding parts are designated by the same reference numerals and description thereof is omitted. It should be noted that in the switching power supply device 21, in the main output circuit 23, the resistor R21 is further provided in series with the resistors R2 and R3, and the transistor TR21 is connected in parallel to the resistor R21. . The base of the transistor TR21 has the transistor TR
A control output is given from the thyristor 17b of the photothyristor 17 in common with the base of FIG.

Therefore, when the terminal CTR is at the High level or is opened from the High level, the thyristor 17b is turned on and the transistor TR21 is also turned on, and the terminals of the resistor R21 are short-circuited. As a result, the voltage of the main output is 2.5 (1+
R2 / R3).

On the other hand, when the terminal CTR becomes low level or is opened from the low level, the thyristor 17b is turned off, the transistor TR21 is also turned off, and the resistor R21 is inserted. As a result, the voltage of the main output is 2.5 (1 + R2 /
(R3 + R21)).

Therefore, during standby, the PWM control IC 12
By the operation of, the voltage applied to the secondary side circuit is lowered, and the power consumption can be further reduced. The control of such two transistors TR21 and TR5 is
This can be realized by arbitrarily taking the potential on the cathode side of the thyristor 17b of the photothyristor 17, and the applicable range of the control signal can be expanded.

FIG. 3 shows the third embodiment of the present invention.
The explanation is based on the following.

FIG. 3 is a block diagram showing an electrical configuration of the switching power supply device 31 according to the third embodiment of the present invention. This switching power supply device 31 is similar to the switching power supply device 11 described above, and corresponding parts are designated by the same reference numerals and description thereof is omitted. It should be noted that in the switching power supply device 31, the operation control circuit 35 further includes the photodiode D31 of the photocoupler PC2 in addition to the configuration of the operation control circuit 15 described above. Correspondingly, in the primary side circuit, P
Triangle wave oscillation frequency setting terminal RT of WM control IC 12
The resistor R6 connected to is provided with a resistor R31 in parallel, and the phototransistor TR31 of the photocoupler PC2 is provided in series with the resistor R31.

Therefore, when the terminal CTR is at the High level or opened from the High level, the phototransistor TR31 is turned on, the resistance R31 is inserted in parallel with the resistance R6, and the resistance value is lowered, so that the oscillation frequency is increased. Get higher This is the PWM control IC1
In 2 is a capacitance CT that determines the oscillation frequency.
This is because the oscillation frequency of C is determined by the time constant of RT × CT.

On the other hand, when the terminal CTR is at the Low level or is opened from the Low level, the phototransistor TR31 is turned off and only the resistor R6 is provided at the terminal RT, and the oscillation frequency is lowered. Thus, the switching frequency during standby can be set separately from the switching frequency determined by the power to be supplied to the load side device when the main output is turned on, and the power consumption during standby can be further reduced. .

FIG. 4 shows the fourth embodiment of the present invention.
The explanation is based on the following.

FIG. 4 is a block diagram showing an electrical configuration of a switching power supply device 41 according to the fourth embodiment of the present invention. The switching power supply device 41 is similar to the switching power supply device 31 described above, and corresponding parts are designated by the same reference numerals and the description thereof will be omitted. It should be noted that in this switching power supply device 41, the transformer Na
Is provided with a separate winding N4, and the output voltage of the winding N4 is rectified and smoothed by a diode D41 and an electrolytic capacitor C41, and then passed through an output circuit 44 realized by a series regulator having an ON / OFF function. The operation state of the output circuit 44 is controlled by the operation control circuit 35.

The ON / OFF control terminal of the output circuit 44 is open when the output is ON, and when the output is down to GND, the output is OFF.
Becomes The ON / OFF control terminal is a transistor T
This transistor T is connected to GND via R41.
The base of R41 is connected to the standby power supply via a resistor R41. The phototransistor TR31 of the photocoupler PC2 is connected in parallel between the base and the emitter of the transistor TR41.

Therefore, when the terminal CTR becomes High level or is opened from High level, the phototransistor TR31 is turned on, whereby the base of the transistor TR41 becomes Low level and the transistor TR41 is turned off. The output from the output circuit 44 is turned on.

On the other hand, when the terminal CTR becomes low level or is opened from the low level, the phototransistor TR31 is turned off, whereby the base of the transistor TR41 becomes high.
The transistor TR41 is turned on and the transistor TR41 is turned on, and the output from the output circuit 44 is turned off.

As a result, unnecessary output from the separate winding N4 during standby can be turned off, and power consumption can be reduced.

FIG. 5 shows the fifth embodiment of the present invention.
The explanation is based on the following.

FIG. 5 is a block diagram showing an electrical configuration of a switching power supply device 51 according to the fifth embodiment of the present invention. The switching power supply device 51 is similar to the switching power supply devices 11 and 31 described above. It should be noted that, in this switching power supply device 51, a charge extracting circuit 56 that rapidly lowers the output voltage when the main output is turned off to enter the standby state is provided in the subsequent stage of the main output circuit 13. It is that you are. The charge extracting circuit 56 includes an electrolytic capacitor C51 for stabilizing the main output, a short-circuit resistor R51 for short-circuiting the terminals of the electrolytic capacitor C51, a transistor TR51 provided in series with the short-circuit resistor R51, and the transistor A pull-up resistor R52 that connects the base of TR51 to the standby power supply and a phototransistor TR31 of the photocoupler PC2 that is connected in parallel between the base and emitter of the transistor TR51 are configured.

Therefore, when the terminal CTR becomes High level or is opened from the High level, the phototransistor TR31 is turned on, whereby the base of the transistor TR51 becomes Low level and the transistor TR51 is turned off. The short-circuit resistor R51 is not inserted between the terminals of the electrolytic capacitor C51, and the main output is turned on.

On the other hand, when the terminal CTR becomes low level or is opened from the low level, the phototransistor TR31 is turned off, whereby the base of the transistor TR51 becomes high.
When the transistor TR51 becomes level, the transistor TR51 is turned on, the short-circuit resistor R51 is inserted between the terminals of the electrolytic capacitor C51, the main output is turned off, and the electric charge thereof is quickly extracted, so that the output voltage is rapidly reduced. .

FIG. 6 shows the sixth embodiment of the present invention.
The explanation is based on the following.

FIG. 6 is a block diagram showing an electrical configuration of a switching power supply device 61 according to the sixth embodiment of the present invention. The switching power supply device 61 is similar to the switching power supply device 41 described above. It should be noted that, in the switching power supply device 61, when the separate output by the separate winding N4 of the transformer Na is provided, there is a time difference in operation timing between the separate output and the main output. is there. In the example of FIG. 6, the separate output side is switched first, and then the main output side is switched.

Therefore, on the other output side, a charging circuit in which a resistor R61 and an electrolytic capacitor C61 are connected in series is provided between the standby power source and GND, and further, in parallel with the electrolytic capacitor C61. The photodiode D61 of the photocoupler PC3 is connected, and the discharge resistor R62 is connected. On the other hand, in the main output circuit 63,
Instead of the transistor TR5, the photo coupler P
A C3 phototransistor TR61 is provided.

Therefore, when the terminal CTR is at the High level or is opened from the High level, the output circuit 44 is first turned on, whereby the charging voltage of the electrolytic capacitor C61 rises and reaches the predetermined level, the photocoupler PC3. Through MOSFET Q2
Is turned on, and the main output is turned on.

On the other hand, when the terminal CTR is at the Low level or is opened from the Low level, the output circuit 44 is first turned off, whereby the charging voltage of the electrolytic capacitor C61 is lowered, and the predetermined value is set. When the level falls below the level, M is passed through the photo coupler PC3.
The OSFET Q2 is turned off and the main output is turned off.

In this way, there can be a time difference between the switching timings of the operations of the two output circuits 63 and 44.

[0087]

As described above, according to the operation control apparatus of the present invention, the operating state of the controlled circuit is changed by the input control signal being High.
In an operation control device configured to turn on at an h level, maintain at an open state, and turn off at a low level, a thyristor that realizes the above operation is a photothyristor, and a diode of the photothyristor is driven by the input control signal, The control output to the controlled circuit is derived by the thyristor of the photothyristor.

Therefore, in the case of a normal thyristor, it is necessary to short-circuit the gate and the cathode in order to make the current between the anode and the cathode less than the holding current in order to turn it off. Therefore, the cathode that is grounded is connected to the photothyristor. By doing so, it can be used in a floating state. As a result, the influence of variations in temperature and thyristor is reduced, the redundancy of the controlled circuit for the input is increased, the degree of freedom in circuit design is expanded, and the design can be facilitated. Further, since the thyristor of the photothyristor can arbitrarily take the potential on the cathode side, this control output can be used also for the control of circuits other than the controlled circuit, and the application range can be expanded.

Further, the switching power supply device of the present invention is
As described above, the controlled circuit is the main output circuit,
Power is supplied from the sub output circuit, which is a standby power supply, and the main output circuit is turned ON / O in response to the input control signal.
The above operation control device is used as an operation control circuit for FF control.

Therefore, the switching power supply device can be easily designed, and other control such as changing the oscillation frequency or changing the setting of the output voltage can be realized by the common operation control circuit. it can.

Furthermore, in the switching power supply device of the present invention, as described above, the operation control circuit is interposed between the power supply lines from the sub output circuit which is the standby power supply, and the diode 17a of the photothyristor, Resistance R
7. A series circuit including a transistor TR2 to which the input control signal is applied to the base and a Zener diode D3 for adjusting the ON voltage of the transistor TR2, and a transistor for connecting the anode of the thyristor 17b of the photothyristor to the standby power supply. TR3 and resistance R
8, a bias resistor R9 connecting the base and emitter of the transistor TR3, and the transistor TR3.
A resistor R10 and a transistor TR4 for connecting the base of the transistor TR4 to GND, a pull-up resistor R11 for connecting the base of the transistor TR4 to the standby power supply, and a diode D4 for applying the input control signal to the base of the transistor TR4. The thyristor 17
A control output is derived from the cathode of b to the main output circuit.

Therefore, the operating state of the main output circuit is
The above operation of turning on the input control signal at the high level, maintaining the open state, and turning off at the low level can be realized by the photothyristor and a simple circuit such as a transistor and a diode.

Further, the switching power supply device of the present invention is
As described above, the main output circuit further includes the resistor R21 in series with the voltage dividing resistors R2 and R3 for feedback of the output voltage to the primary side, and the resistor R2.
1 has a transistor TR21 connected in parallel, and supplies a control output from the operation control circuit to the base of the transistor TR21.

Therefore, when the input control signal becomes High level or becomes open from the High level, the duty of switching rises and the voltage of the main output becomes high, and the input control signal becomes Low level or the Low level. When it becomes open from, the duty of switching decreases and the voltage of the main output decreases. In this way, the voltage applied to the secondary circuit during standby can be reduced, and power consumption can be further reduced.

Furthermore, in the switching power supply device of the present invention, as described above, the resistor R6 for setting the oscillation frequency of the control circuit for controlling the switching on the primary side is connected in parallel with the resistor R6.
31, a phototransistor TR31 of the photocoupler PC2 is provided in series with the resistor R31, and the operation control circuit further has a photodiode D3 of the photocoupler PC2 in series with the thyristor 17b.
1 is set.

Therefore, when the input control signal is at the High level or is opened from the High level and the main output circuit is turned on, the phototransistor TR31 is turned on and the resistor R31 is inserted in parallel with the resistor R6. When the resistance value is decreased, the switching frequency is increased, the input control signal is at the Low level or opened from the Low level, and the main output circuit is turned off, the phototransistor TR31 is turned off.
Then, the resistor R31 is not inserted, and the oscillation frequency becomes low. Thus, the switching frequency during standby can be set separately from the switching frequency determined by the power to be supplied to the load side device when the main output is turned on, and the power consumption during standby can be further reduced. .

Further, the switching power supply device of the present invention is
As described above, another winding is provided on the secondary side of the transformer, and the operation state of the output circuit of the winding is also controlled by the operation control circuit.

Therefore, it is possible to turn off the unnecessary output from the separate winding during standby and reduce the power consumption.

Furthermore, as described above, the switching power supply device of the present invention is provided with the charge extracting circuit at the subsequent stage of the main output circuit, and the operation state thereof is also controlled by the operation control circuit.

Therefore, when the main output circuit is turned off, the charge extracting circuit operates, the electric charge of the main output can be quickly extracted, and the output voltage can be rapidly reduced.

Further, the switching power supply device of the present invention is
As described above, the separate winding is provided on the secondary side of the transformer, and one of the output circuit of the winding and the main output circuit is provided with the control output from the operation control circuit, and the other is provided with the control output from the one. Controlled by.

Therefore, there can be a time difference in the operation timing between the load of the separate winding and the load of the main output.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a switching power supply device according to a first embodiment of the present invention.

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

FIG. 3 is a block diagram showing an electrical configuration of a switching power supply device according to a third embodiment of the present invention.

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

FIG. 5 is a block diagram showing an electrical configuration of a switching power supply device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing an electrical configuration of a switching power supply device according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing an electrical configuration of a typical conventional switching power supply device.

[Explanation of symbols]

11, 21, 31, 31, 41, 51, 61 Switching power supply device 12 PWM control IC 13, 23, 63 Main output circuit 14 Sub output circuit 15, 35 Operation control circuit 16 Shunt regulator 17 Photothyristor 17a Diode 17b Thyristor 44 Output circuit 56 Charge extraction circuit B DC power sources C1 to C3, C41, C51 Electrolytic capacitors D1, D4, D5, D41 Diodes D2, D31, D61 Photodiode D3 Zener diode N, Na Transformer N1 Primary winding N2 Secondary winding N3 Auxiliary winding Line N4 Separate winding PC1, PC2 Photo coupler Q1 Main switching MOSFET Q2 MOSFET (for output control) R1, R5, R9, R13 Bias resistance R2, R3 Resistance (voltage dividing resistance) R4, R6, R7, R8, R10, R21, R31
Resistors R11, R52 Pull-up resistor R51 Short-circuit resistor R62 Discharge resistor TR1, TR31 Phototransistor TR2-TR5, TR21, TR41, TR51 Transistor

Claims (8)

[Claims] 1. An operating state of a controlled circuit is ON when an input control signal is at a high level, continuous when it is in an open state, and Lo.
An operation control device for turning off at a w level, comprising: a photothyristor, driving a diode of the photothyristor by the input control signal, and deriving a control output to the controlled circuit by the thyristor of the photothyristor. An operation control device characterized by: 2. The controlled circuit is a main output circuit, and power is supplied from a sub output circuit which is a standby power supply, and the main output circuit is turned on / off in response to the input control signal.
A switching power supply device using the operation control device according to claim 1 as an operation control circuit for F control. 3. The operation control circuit, a diode TRa of the photothyristor interposed between power supply lines from the sub output circuit which is a standby power supply, a resistor R7, and a transistor TR2 to which the input control signal is applied to the base. And a series circuit including a Zener diode D3 for adjusting the ON voltage of the transistor TR2, a transistor TR3 and a resistor R8 for connecting the anode of the thyristor 17b of the photothyristor to the standby power supply, and a base-emitter of the transistor TR3. Bias resistor R9 connecting between them, resistor R10 connecting the base of the transistor TR3 to GND, and transistor TR4
A pull-up resistor R11 for connecting the base of the transistor TR4 to the standby power supply, and a diode D4 for supplying the input control signal to the base of the transistor TR4. 3. The switching power supply device according to claim 2, wherein the control output is derived to the output circuit. 4. The main output circuit is connected in series with voltage dividing resistors R2 and R3 for feedback of an output voltage to the primary side,
4. The resistor R21 is further provided, and a transistor TR21 connected in parallel with the resistor R21 is provided, and a control output from the operation control circuit is given to the base of the transistor TR21. Switching power supply. 5. In a control circuit for controlling switching on the primary side, a resistor R31 is provided in parallel with a resistor R6 for setting the oscillation frequency, and a phototransistor TR31 of a photocoupler PC2 is provided in series with the resistor R31. The operation control circuit further includes the thyristor 17
5. The switching power supply device according to claim 3, wherein a photodiode D31 of the photocoupler PC2 is provided in series with b. 6. The secondary winding of the transformer has a separate winding, and the operating state of the output circuit of the winding is also controlled by the operation control circuit. Switching power supply. 7. The switching power supply device according to claim 2, further comprising a charge extracting circuit provided at a stage subsequent to the main output circuit, the operation state of which is controlled by the operation control circuit. 8. A secondary winding of the transformer has a separate winding, and in one of the output circuit of the winding and the main output circuit, the control output from the operation control circuit is given, and the other is provided from one side. The switching power supply device according to claim 2, wherein the switching power supply device is controlled by a control output.