JP3398354B2 - Multi-output power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multi-output power supply device.

[0002]

2. Description of the Related Art For example, in plant equipment, various electric and electronic devices such as a program controller, a sequencer, and a sensor circuit are mounted, and these electric and electronic devices are stable in order to operate an integrated circuit. DC voltage (for example, about 5 to 10 volts) is required. As a power supply device for obtaining a stable DC voltage, a power supply device of a switching system, a dropper system or the like is known. By using these stabilized power supply devices, it is possible to obtain a desired stable DC voltage by transforming, rectifying, and smoothing a commercial power supply voltage such as AC 100 V or 200 V.

Further, when it is necessary to install a large number of electric and electronic devices which require a DC power source, it is necessary to install a stabilized power supply device for each of the devices, thereby increasing the scale of the device. Since it is often disadvantageous in terms of device configuration such as cost increase, a multi-output power supply device capable of obtaining a plurality of output voltages with respect to one input voltage has recently been proposed and put into practical use. .

FIG. 4 is a circuit diagram showing the structure of a conventional multi-output power supply device (in the figure, the case of three outputs is shown).

As shown in the figure, the multi-output power supply device 101
Is an input circuit 102 and a three-channel output circuit 103
To 105, the input circuit 102 and the output circuit 103 to 105
And a transformer TR101 interposed between and. The AC power source E connected to the input circuit 102
By transforming, rectifying, and smoothing the AC voltage supplied from 101, each of the three-channel output circuits 103 to 10
From 5, it is possible to obtain independent DC voltage outputs.

The input circuit 102 rectifies and smoothes the AC voltage supplied from the AC power source E101 and smoothes it (converts it into a DC voltage), and a switching M.
OS-FET 107, overcurrent detector 108, PWM
The control circuit 109 and the transformer TR10.
No. 1 primary coil L101 and MOS-FET 107
And a series connection circuit of the overcurrent detector 108 and the overcurrent detector 108 are connected to the output terminal of the rectifying and smoothing circuit 106. Also, MOS
The gate of the -FET 107 is connected to the PWM control circuit 109 so that the MOS-FET 107 can be switched on and off in synchronization with the pulse signal output from the PWM circuit 109.

The output signal of the overcurrent detector 108 is PWM
The MOS-FE is provided so that the current supplied to the control circuit 109 and flowing through the primary coil L101 does not exceed a predetermined value.
The duty ratio of the pulse signal supplied to T107 is controlled.

The output circuit 103 is a rectifying / smoothing circuit 110 for rectifying and smoothing an AC voltage generated across the secondary coil L102 of the transformer TR101, and an output terminal 103.
When an overvoltage occurs between a and 103b, an overvoltage detector 111 for detecting the overvoltage and the output terminals 103a and 103
Output voltage detector 11 for detecting the voltage value output from b
2 and an overcurrent detector 121 that detects when an electric current supplied to a load (not shown) connected to the output terminals 103a and 103b becomes an overcurrent.

The overvoltage detection signal detected by the overvoltage detector 111, the overcurrent detection signal detected by the overcurrent detector 121, and the output voltage signal detected by the output voltage detector 112 are the photocoupler PC101. , PC10
2 is supplied to the PWM circuit 109.

The output circuit 104 is a transformer TR1.
Mag amplifier 1 connected to the secondary coil L103 of 01
13, rectifying / smoothing circuit 114, and output terminals 104a, 1
Output voltage detector 1 for detecting the voltage value generated between 04b
15, an overcurrent detector 122, and a control circuit 124 that controls saturation and non-saturation of the mag amplifier 113. Similarly, the output circuit 105 includes a mag-amp 116 connected to the secondary coil L104 of the transformer TR101.
Rectifying and smoothing circuit 117 and output terminals 105a, 105
Output voltage detector 118 for detecting the voltage value generated between points b
And an overcurrent detector 123 and a control circuit 125.

In the multi-output power supply device 101 configured as described above, the pulse voltage output from the PWM control circuit 109 causes the MOS-FET 107 to turn on and off at a predetermined timing, thereby rectifying and smoothing. Since the DC voltage output from the circuit 106 is applied to the primary coil L101 of the transformer TR101 in a pulsed manner,
An AC voltage corresponding to the coil winding ratio is generated in each of the secondary coils L102 to L104. The AC voltage is rectified and smoothed by the rectifying / smoothing circuits 110, 114, 117, and then output to each output terminal. In this way, it is possible to separately extract the DC voltage from the output circuits 103 to 105 of a plurality of channels (three channels in this example).

When an overvoltage or overcurrent occurs in the output circuit 103, the occurrence of the overvoltage or overcurrent is detected by the overvoltage detector 111 or the overcurrent detector 121. Since the signal is supplied to the PWM control circuit 109 via the photocouplers PC101 and PC102, in the PWM control circuit 109,
In order to suppress this overvoltage and overcurrent, MOS-FET
Processing for reducing the duty ratio of the pulse signal output to 107 is performed.

Further, when the voltage value generated across the output terminals 103a and 103b fluctuates, this fluctuation is detected by the output voltage detector 112, and this detection signal is sent through the photocoupler PC102 to the PWM control circuit 109. Therefore, the PWM control circuit 109 appropriately adjusts the duty ratio of the pulse signal to be output and controls so that the output voltage becomes a desired voltage.

On the other hand, in the output circuits 104 and 105, when the output voltage fluctuates, this fluctuation occurs in the output voltage detector 1.
15 and 118, and control circuits 124 and 125
Receives the detection signal and adjusts the saturation and non-saturation of the mag-amplifiers 113 and 116 so that the output voltage becomes a desired voltage. Further, when an overcurrent occurs in the output circuits 104 and 105, the overcurrent detectors 122 and 123 detect the occurrence of the overcurrent, and the mag amplifiers 113 and 116 are detected.
Receives this detection signal and controls so as to suppress the current value.

In this way, the output voltage of each of the output circuits 103 to 105 is controlled to a desired voltage, and when an overcurrent occurs, the current value is suppressed to connect the output circuit 103 to 105 or the output circuit. It prevents the load (equipment) from overheating and burning.

However, in the conventional multi-output power supply device 101 configured as described above, when an overcurrent occurs in the output circuits 103 to 105, such as when the load side is short-circuited (short circuit), overcurrent detection is performed. Although this can be detected by the detectors 121 to 123, in the unlikely event that normal overcurrent cannot be detected due to a trouble such as damage to the components constituting the overcurrent detectors 121 to 123,
The circuit patterns of the output circuits 103 to 105 are burnt out,
May damage components. In addition, the load side components may be damaged or burnt.

Particularly in the case of the multi-output power supply device 101,
If a short circuit accident occurs in the output circuit of one channel among the output circuits 103 to 105 of the three channels, all the power on the input circuit 102 side may be concentrated in the output circuit of this channel, resulting in excessive damage.

Therefore, in order to avoid such troubles, in the past, a load side circuit (apparatus) connected to the multi-output power supply device 101 is provided with a fuse for overcurrent protection, a circuit protector, or the like. In order to minimize damage even in the event of overcurrent, measures such as using highly flame-retardant materials and materials that do not cause ignition or combustion are used as parts used in the load side circuit. It was taken.

[0019]

As described above, in the conventional multi-output power supply device 101, the transformer T
Each output circuit 103 to 10 connected to the secondary side of R101
No. 5 has overcurrent detectors 121 to 123, respectively, and when an overcurrent occurs, it has a function of protecting the circuit by suppressing this current, but this protection function is normal. When it does not operate, there is a drawback that the circuit pattern is burnt out or the load side circuit connected to the output circuit is damaged or burnt out.

The present invention has been made in order to solve such a conventional problem, and an object thereof is to provide multiple outputs capable of more reliably limiting the output power of the output circuit to a predetermined value. To provide a power supply device.

[0021]

These objects are achieved by the present invention described in (1) to (8) below.

(1) An output circuit having a transformer having a primary side coil and a plurality of secondary side coils, and having rectifying means is connected to each of the secondary side coils, and each of the output circuits is connected. In the multi-output power supply device for obtaining independent DC power, the output circuits of the plurality of channels are
A first detection unit that detects the output current of the output circuit is provided on the output side of the rectifying unit, and a first output limiting unit that limits the output power of the output circuit to a first value; Second output limiting means for limiting the output power of the output circuit to a second value different from the first value by providing a second detector for detecting the output current of the circuit on the output side of the rectifying means; ,
A multi-output power supply device comprising:

(2) The first output limiting means limits the output power on the secondary side of the transformer, and the second output limiting means outputs the output power on the primary side or the secondary side of the transformer. The multi-output power supply device according to (1) above, wherein

(3) The multi-output power supply device according to (1) or (2), wherein the second value is set to be larger than the first value.

(4) The first value is set to 101 to 500% of the maximum output power that can be constantly taken out, and the second value is 106 of the maximum output power that can be taken out constantly.
The multi-output power supply device according to any one of (1) to (3) above, which is set to ˜600%.

(5) The first output limiting means is for protecting the multi-output power supply device itself, and the second output limiting means is for protecting equipment connected to the output circuit. The multi-output power supply device according to any one of (1) to (4) above.

(6) In any one of the above (1) to (5), the first output limiting means of the first output limiting means and the second output limiting means operates preferentially. Multi-output power supply.

(7) The first output limiting means and the second output limiting means are respectively overcurrent protection circuits,
The above-mentioned having at least one selected from the group consisting of an overvoltage protection circuit having a function of overcurrent protection, an overheat protection circuit, a thermistor, a posistor, a fuse, a three-terminal regulator, a circuit protector, a relay, a fuse resistor and a temperature fuse resistor. The multi-output power supply device according to any one of 1) to (6).

(8) In a transformer having a primary side coil and a plurality of secondary side coils, a pulse voltage is applied to the primary side coil and an output circuit equipped with a rectifying means is provided for each of the secondary side coils. In a multi-output power supply device which is connected to each of the output circuits to obtain independent DC power from each of the output circuits, switching means for applying a DC voltage to the primary side coil in a pulsed manner, and a pulse signal to the switching means Pulse width control means for controlling the duty ratio of the pulse signal, wherein each of the output circuits detects a mag-amp connected to the secondary coil and an output current of the output circuit. A first output control unit for providing a control signal to the mag-amplifier to limit the output power of the output circuit to a first value by providing a detection unit No. 1 on the output side of the rectifying means. Control means and a second detection section for detecting an output current of the output circuit are provided on the output side of the rectifying means, and the output power of the output circuit is set to a second value larger than the first value. And a second output control means for outputting a control signal to the mag-amplifier so as to limit the power supply to the multi-output power supply device.

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION A multi-output power supply device of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

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

As shown in the figure, the multi-output power supply device 1 is
Transformer TR1 and primary coil L of the transformer TR1
1 is connected to the input circuit 2 and three-channel output circuits 3 to 5 connected to the secondary coils L2 to L4 of the three systems of the transformer TR1, and the alternating current connected to the input circuit 2 The AC voltage supplied from the power source E1 is transformed, rectified, and smoothed, and each of the three-channel output circuits 3 to 5 operates independently to output a desired stable DC voltage (electric power).

The input circuit 2 rectifies and smoothes the AC voltage supplied from the AC power source E1 to obtain a DC voltage (converts it into a DC voltage), and a switching M circuit.
OS-FET (switching means) 7 and the input circuit 2
Overcurrent detector 8 that detects when an overcurrent flows to the
And a PWM control circuit (pulse width control means) 9, and a primary side coil L1 of the transformer TR1 and an MO.
A series connection circuit of the S-FET 7 and the overcurrent detector 8 is connected to the output terminal of the rectifying / smoothing circuit 6.

The gate of the MOS-FET 7 is PW.
The MOS-FET 7 is connected to the M control circuit 9 and is turned on / off in synchronization with the pulse signal output from the PWM control circuit 9.

The output of the overcurrent detector 8 is the PWM control circuit 9
The PWM control circuit 9 controls so that the current flowing through the primary coil L1 does not exceed a predetermined value by reducing the duty ratio of the pulse signal to be output when the overcurrent is detected. To do.

The output circuit 3 includes a rectifying / smoothing circuit (rectifying means) 10 for rectifying and smoothing an AC voltage generated across the secondary coil L2 of the transformer TR1, and output terminals 3a, 3b of the output circuit 3. When an overvoltage occurs between them, an overvoltage detector 11 that detects the overvoltage, an output voltage detector 12 that detects the voltage values output from the output terminals 3a and 3b, and a current flowing through the output circuit 3 are overcurrent. And a current detector (first detection unit) 13 that detects the current when the current becomes high, and a current detector (second detection unit) 14 that is arranged in series with the current detector 13. ing.

The current detector 13 is connected to the overcurrent protection circuit 29, and the current detector 14 is connected to the overcurrent protection circuit 30.

The output terminal of the overcurrent protection circuit 29 is connected to the PWM control circuit 9 via the photocoupler PC1 and the output terminal of the overvoltage detector 11 is connected to the photocoupler PC2.
The output terminal of the output voltage detector 12 and the output terminal of the overcurrent protection circuit 30 are both connected to the PWM control circuit 9 via the photocoupler PC3.
It is connected to the.

The overcurrent protection circuits 29 and 30 are as follows.
For example, the characteristics of voltage change with respect to current change are fold-back characteristics ("F" shape), F-shape characteristics ("F" shape), constant current drooping characteristics (constant current drooping type), and shutdown characteristics. Etc.

The output circuit 4 includes a mag-amplifier 15 connected to the secondary coil L3 of the transformer TR1 and a rectifying / smoothing circuit (rectifying means) 16 for rectifying and smoothing the voltage generated in the secondary coil L3. Output terminals 4a, 4 of the output circuit 4
When the output voltage detector 17 that detects the voltage between b, the overvoltage detector 51 that detects the overvoltage in the output circuit 4 when it occurs, and the current flowing in the output circuit 4 becomes the overcurrent, Two systems of current detectors 18 and 19 for detecting this
(First detection unit 18, second detection unit 19).

Further, the output circuit 4 receives the detection signal of the output voltage detector 17 and the detection signal of the current detector 18, and controls the saturation and non-saturation of the mag-amplifier 15, and the current detector. The control circuit 21 controls the saturation and non-saturation of the mag-amplifier 15 in response to the detection signal of 19. The output terminal of the overvoltage detector 51 is
It is connected to the PWM control circuit 9 via the photocoupler PC4.

Similarly to the output circuit 4, the output circuit 5 also rectifies and smoothes the voltage generated in the mag-amp 22 connected to the secondary coil L4 of the transformer TR1 and the secondary coil L4. Rectifying and smoothing circuit (rectifying means) 2
3, an output voltage detector 24 for detecting a voltage generated between the output terminals 5a and 5b of the output circuit 5, and an overvoltage detector 5 for detecting an overvoltage when the output circuit 5 is generated.
2 and two systems of current detectors 25 and 26 (first detecting unit 25 and second detecting unit 26) that detect an overcurrent of the current flowing through the output circuit 5. It has.

Further, the output circuit 5 receives the detection signal of the output voltage detector 24 and the detection signal of the current detector 25 and controls the saturation and non-saturation of the mag-amplifier 22 and the current detector. A control circuit 27 for controlling the saturation and non-saturation of the mag-amplifier 22 in response to the detection signal of 26. The output terminal of the overvoltage detector 52 is
It is connected to the PWM control circuit 9 via the photocoupler PC5.

Here, in the output circuit 3, the current detector 13, the overcurrent protection circuit 29 and the PWM control circuit 9 constitute a first output limiting means, and the current detector 14,
Second by the overcurrent protection circuit 30 and the PWM control circuit 9
Output limiting means is configured. Further, the current detector 13 and the overcurrent protection circuit 29 form a first output control means, and the current detector 14 and the overcurrent protection circuit 30 form a second output control means.

In the output circuit 4, the current detector 18,
The control circuit 20 and the mag-amplifier 15 constitute a first output limiting means, and the current detector 19, the control circuit 21 and the mag-amplifier 15 constitute a second output limiting means. Further, the current detector 18 and the control circuit 20 constitute a first output control means, and the current detector 19 and the control circuit 21.
And constitute the second output control means.

In the output circuit 5, the current detector 25,
The control circuit 27 and the mag-amp 22 constitute a first output limiting means, and the current detector 26, the control circuit 28 and the mag-amp 22 constitute a second output limiting means. Further, the current detector 25 and the control circuit 27 constitute a first output control means, and the current detector 26 and the control circuit 28.
And constitute the second output control means.

Next, the operation (operation) of the multi-output power supply device 1 will be described. When an AC voltage of, for example, 100 V or 200 V is output from the AC power source E1, the AC voltage is rectified and smoothed by the rectifying / smoothing circuit 6,
A DC voltage is output from the rectifying / smoothing circuit 6. here,
When the PWM control circuit 9 operates and a pulse signal having a desired duty ratio is output, the pulse signal is applied to the gate of the switching MOS-FET 7, so that the MOS-FET 7 is synchronized with this pulse signal. Then, it turns on and off. As a result, the DC voltage output from the rectifying / smoothing circuit 6 is applied in pulses to the primary coil L1 of the transformer TR1. Therefore, at both ends of each of the secondary coils L2 to L4 of the transformer TR1,
An AC voltage corresponding to the coil winding ratio is generated, and this AC voltage is converted into a DC voltage by the rectifying / smoothing circuits 10, 16 and 23 provided in the output circuits 3 to 5,
It is supplied to the output terminals of the output circuits 3 to 5.

As a result, between the output terminals 3a and 3b, between the output terminals 4a and 4b, and between the output terminals 5a and 5b,
Independent DC voltages are generated, and by connecting a load side circuit (device) (not shown) to each output terminal, the load side circuit can be operated stably.

When the voltage output from the output circuit 3 fluctuates, that is, when the output voltage of 5 V rises to 6 V or drops to 4 V, the output voltage is changed. This voltage fluctuation is detected by the detector 12, and this detection signal is supplied to the PWM control circuit 9 via the photocoupler PC3. Then, the PWM control circuit 9 receives the detection signal, adjusts the duty ratio of the pulse signal to be output, and controls the output voltage to have a desired value.

Further, when the output voltage of the output circuit 3 becomes an overvoltage, the overvoltage detector 11 detects the occurrence of the overvoltage, and thus this detection signal is supplied to the PWM control circuit 9 via the photocoupler PC2. The duty ratio of the output pulse is reduced by the control of the PWM control circuit 9 to reduce the output voltage.

In the load side circuit (equipment) connected to the output terminals 3a and 3b of the output circuit 3, for example, when a short-circuit accident occurs, the current flowing through the output circuit 3 increases to cause an overcurrent. If it becomes, the current detectors 13 of the two systems,
At 14, the occurrence of overcurrent is detected. The overcurrent protection circuit 29 receives the overcurrent detection signal from the current detector 13 and outputs a control signal to reduce the output current,
This control signal is supplied to the PWM control circuit 9 via the photocoupler PC1. Similarly, the overcurrent protection circuit 30 receives an overcurrent detection signal from the current detector 14 and outputs a control signal to reduce the output current. This control signal is sent to the PWM control circuit 9 via the photocoupler PC3. Supplied.

The PWM control circuit 9 receives one of the control signals and reduces the duty ratio of the output pulse signal to reduce the overcurrent generated in the output circuit 3. This causes overcurrent (overpower) in the output circuit 3.
Even if occurs, this overcurrent can be suppressed, and two systems (a system composed of the current detector 13, the overcurrent protection circuit 29, and the photocoupler PC1)
Even if one of the current detector 14, the overcurrent protection circuit 30 and the photocoupler PC3) fails and normal detection and control cannot be performed, the operation of the other system reliably prevents overshoot. Since the current can be blocked, it is possible to prevent the occurrence of troubles such as burnout or damage of the output circuit 3 and the load side circuit connected thereto.

In this case, the system including the current detector 13, the overcurrent protection circuit 29 and the photocoupler PC1, that is, the first power limiting means limits the output power of the output circuit 3 to the first value (output). The current is limited to the current conversion value of the first value), and the system consisting of the current detector 14, the overcurrent protection circuit 30 and the photocoupler PC3, that is, the second power limiting means controls the output power of the output circuit 3. Limit to the second value (limit the output current to the current conversion value of the second value).

On the other hand, in the output circuit 4, since the output voltage is detected by the output voltage detector 17, when a variation occurs in the output voltage generated between the terminals 4a and 4b, this variation is detected by the output voltage detector. It is detected by 17, and this detection signal is supplied to the control circuit 20. Then, the control circuit 20
Controls the saturation and non-saturation of the mag amplifier 15 so that the output voltage becomes a predetermined value.

Further, if a trouble such as a short circuit accident occurs in the load side circuit (equipment) connected to the output terminals 4a and 4b of the output circuit 4, an overcurrent may flow in the output circuit 4. become. This overcurrent is detected by the current detectors 18 and 19 of two systems.
Is supplied to the control circuit 20, and the current detector 19
Is supplied to the control circuit 21, the output current (output voltage) of the output circuit 4 is lowered by controlling the saturation or non-saturation of the mag amplifier 15 by either one of the control circuits 20 and 21. Let As a result, the output circuit 4
And, the circuit on the load side connected thereto can be protected.

In this case, the system including the current detector 18 and the control circuit 20, that is, the first power limiting means limits the output power of the output circuit 4 to the first value (the output current is the first value). Current limit value), current detector 19
In the system including the control circuit 21 and the second power limiting means, the output power of the output circuit 4 is limited to the second value (the output current is limited to the current conversion value of the second value).

Similarly to the output circuit 4 described above, in the output circuit 5, when an overcurrent occurs, the current detectors 25 and 26 detect the occurrence of the overcurrent, and the control circuits 27 and 28. Since the saturation or non-saturation of the mag amplifier 22 is controlled by either one of them, the output current of the output circuit 5 can be reduced, and the output circuit 5 and the load side circuit (device) connected thereto can be protected. be able to.

In this case, the system including the current detector 25 and the control circuit 27, that is, the first power limiting means limits the output power of the output circuit 5 to the first value (the output current is the first value). Current limit value), current detector 26
In the system including the control circuit 28, that is, the second power limiting means, the output power of the output circuit 5 is limited to the second value (the output current is limited to the current conversion value of the second value).

In this way, according to the multi-output power supply device 1 of this embodiment, the output circuits 3 to 5 of the respective channels are provided.
However, since each of them is provided with two systems of output limiting means (first output limiting means and second output limiting means), when an overcurrent occurs in the output circuits 3 to 5, it is surely prevented. Even if a trouble occurs in which one of the output limiting means fails, the overcurrent can be surely prevented if the other output limiting means operates normally. This significantly improves reliability and safety.

In the first embodiment described above, in the output circuit 3, the control signal output from the overcurrent protection circuits 29 and 30 is input to the input circuit 2 when an overcurrent occurs in the output circuit 3. The output currents are reduced by feeding back to the PWM control circuit 9 provided in the output circuits 4 and 5, and when an overcurrent occurs in the output circuits 4 and 5, the overcurrent detection signal is output to the mag amp 15. , 22 to suppress the overcurrent, a single output circuit may combine these.

That is, for example, the mag amplifier 15 is controlled by using the detection signal of the current detector 18 of one system of the output circuit 4, and the detection signal of the current detector 19 of the other system is PWM.
The control circuit 9 may be fed back to reduce the output current. In contrast to this, the detection signal of the current detector 18 of one system of the output circuit is fed back to the PWM control circuit 9 to reduce the output current, and the detection signal of the current detector 19 of the other system is used. It is also possible to adopt a configuration in which the mag-amplifier 15 is controlled.

It is also possible to set different current values (overcurrent detection values) when overcurrent is detected in the two current detectors.

For example, the case of the output circuit 4 will be representatively described. The overcurrent detection value by the current detector 18 is set to the current conversion value of the first value, and the overcurrent detection value by the current detector 19 is set as the first value. It is also possible to use a second-value current conversion value that is larger than the above value.

With such a configuration, the current detector 18
And the first output limiting means including the control circuit 20 operates preferentially. That is, the current detector 18 side having the first value of the current conversion value serves as the main output limiting means, and the current detector 19 side having the second value of the current conversion value has the current detector 18 side. It serves as an auxiliary output limiting device that operates when a failure occurs.

Also, the first output limiting means is for protecting the multi-output power supply device 1 itself, and the second output limiting means is the load side circuit (device) connected to the output circuit 4.
Can also be for protection. in this case,
The first output limiting means protects not only the multi-output power supply device 1 itself but also the load side circuit connected to the output circuit 4, and the second output limiting means connects the output circuit 4 to the output circuit 4. It goes without saying that not only the circuit on the load side but also the multi-output power supply device 1 itself is protected.

Although description of the output circuits 3 and 5 is omitted, the same modifications as the output circuit 4 are possible.

Further, the overcurrent detection values in the current detectors of the two systems are set to different values, and the mag-amplifier is controlled by the detection signal of the current detector of one system, and the current detectors of the other system are used. The PWM control circuit 9 may be controlled by the detection signal.

That is, for example, the mag amp 15 is controlled by using the detection signal of the current detector 18 of one system of the output circuit 4, and the detection signal of the current detector 19 of the other system is used by the PWM control circuit 9. A configuration for controlling the output, further, the overcurrent detection value by the current detector 18 is a current conversion value of the first value, and the overcurrent detection value by the current detector 19 is a second value larger than the first value. It is also possible to use the current conversion value of.

With such a configuration, when the value of the current flowing through the output circuit 4 rises and exceeds the current conversion value of the first value, the mag amp 15 outputs the current based on the detection signal from the current detector 18. Acts to reduce the current,
When the current conversion value of the second value is exceeded, the PWM control circuit 9 operates to reduce the output current based on the detection signal from the current detector 19. That is, transformer TR
The operation of limiting the output current (output power) is performed in the order of 1, the secondary side, and the primary side.

In contrast to the above, for example, the output circuit 4
, Using the detection signal of the current detector 18 of one system
The output of the WM control circuit 9 is controlled, and the mag amp 15 is controlled by using the detection signal of the current detector 19 of the other system. Further, the overcurrent detection value by the current detector 18 is set to the first value of the current. It is also possible to use the converted value and the overcurrent detection value of the current detector 19 as the current converted value of the second value larger than the first value.

As described above, the first output limiting means limits the output current (output power) on the primary side or the secondary side of the transformer TR1, and the second output limiting means operates the transformer TR1.
Can be configured to limit the output current (output power) on the primary side or the secondary side of the transformer TR1. Of these, the first output limiting means outputs the output current (output power) on the secondary side of the transformer TR1. ), The second output limiting means outputs the output current (output power) on the primary side or the secondary side of the transformer TR1.
Is preferably configured to limit

In the first embodiment described above, the case where the output circuit provided on the secondary side of the transformer has three channels has been described. However, the present invention is not limited to this, and two channels or It is also possible to have four or more channels.

Further, in the above-described first embodiment, the example in which the output current or the output voltage is reduced when the overcurrent or the overvoltage occurs in the output circuit has been described. However, when the overcurrent or the overvoltage occurs. To each,
It is also possible to adopt a configuration in which the output is stopped.

Here, the above-mentioned first value is preferably set to about 101 to 500% of the maximum power (maximum output power) that the corresponding output circuit can output steadily (continuously). More preferably, it is set to about 101 to 150%.

The second value is preferably set to about 106 to 600% of the maximum power (maximum output power) that the corresponding output circuit can output steadily (continuously), More preferably, it is set to about 106 to 200%. However, the first value and the second value may be reversed or the same.

Specifically, the current conversion value of the first value and the current conversion value of the second value are, for example, 100 V, respectively.
In the case of A limitation, it can be set as shown in Table 1 below, and in the case of 250 VA limitation, it can be set as shown in Table 2 below.

The maximum output currents in Tables 1 and 2 below are maximum currents (maximum output currents) that the output circuit can output steadily (continuously). The maximum output power is represented by a product of an output voltage and the maximum output current, the first value is represented by a product of an output voltage and a current conversion value of the first value, and the second The value is represented by the product of the output voltage and the current conversion value of the second value.

[0083]

[Table 1]

[0084]

[Table 2]

Next, a multi-output power supply device according to the second embodiment will be described. FIG. 2 is a circuit diagram showing the configuration of the multi-output power supply device according to the second embodiment of the present invention.

As shown in the figure, the multi-output power supply 31
Is a transformer TR11, an input circuit 32 connected to the primary coil L11 of the transformer TR11, and a transformer T11.
R11 three-system secondary side coils L12, L13, L14
The three-channel output circuits 33 to 35 connected to the input circuit 2 are used to transform and rectify the AC voltage supplied from the AC power supply E11 connected to the input circuit 2 as in the first embodiment. , And is operated so as to output a desired stable DC voltage (electric power) independently from each of the three-channel output circuits 33 to 35.

The input circuit 32 is the input circuit 2 shown in FIG.
A rectifying / smoothing circuit 36 for rectifying and smoothing the AC voltage output from the AC power supply E11, and a MOS-FET (switching means) 3 for switching.
7, an overcurrent detector 38, and a PWM control circuit 39.

The output circuit 33 includes a mag-amplifier 41 connected to the secondary coil L12 of the transformer TR11, a rectifying / smoothing circuit (rectifying means) 40 installed on the rear side of the mag-amplifier 41, and an output of the output circuit 33. Terminals 33a, 33b
An output voltage detector 42 for detecting a voltage generated between them and an overvoltage detector 43 for detecting an overvoltage of the output voltage are provided. Furthermore, this output circuit 3
3 is a current detector 44, 45 (first detector 44, second detector 45) of two systems for detecting a current flowing in the output circuit 33, and a voltage value detected by the output voltage detector 42. Control circuit 46 for controlling saturation and non-saturation of the mag-amplifier 41 so that the output voltage becomes a desired output voltage, and one current detector 44.
Output current (output power) by controlling the saturation and non-saturation of the mag-amplifier 41 when the occurrence of overcurrent is detected in
The output current (output power) is reduced by controlling the saturation and non-saturation of the mag-amplifier 41 when the occurrence of an overcurrent is detected by the control circuit 47 that controls so as to reduce And a control circuit 48 for controlling the operation.

The output signal of the overvoltage detector 43 is output to the PWM control circuit 39 via the photocoupler PC11. Since the other two output circuits 34 and 35 have the same configuration as the output circuit 33, the suffix "-1" is added to each component of the output circuit 34.
Is attached to the output circuit 35, and the suffix "-2" is attached to the output circuit 35, and the description of the configuration is omitted. In addition, the overvoltage detector 4
Photocouplers PC12 and PC13 are interposed between 3-1 and 43-2 and the PWM control circuit 39.

Next, the operation (operation) of the multi-output power supply device 31
Will be described. The MOS-FET 37 shown in FIG.
Since the ON / OFF is switched by the pulse signal output from the PWM control circuit 39, the DC voltage output from the rectifying / smoothing circuit 36 becomes a pulse voltage signal and is applied to the primary side coil L11 of the transformer TR11. It As a result, an AC voltage corresponding to the winding ratio is generated in each of the secondary coils L12 to L14. The AC voltage generated in the secondary coil L12 of the output circuit 33 is rectified by the rectifying / smoothing circuit 40 and then supplied to a load side circuit (device) (not shown) connected to the output terminals 33a and 33b.

Here, when the output current of the output circuit 33 becomes an overcurrent, the occurrence of the overcurrent is detected by the current detectors 44 and 45 of the two systems, and this detection signal is used as the detection signal.
7,48. Then, the control circuits 47 and 48
Under one of the controls, the saturation and non-saturation of the mag-amplifier 41 are controlled to limit the current flowing through the output circuit 33. As a result, similar to the first embodiment, it is possible to prevent the occurrence of troubles such as burnout and damage of the circuit. In addition, as in the first embodiment, two systems of current detectors 44,
Even if one of the 45 and the control circuits 47, 48 fails, the operation of the current detector and the control circuit of the other system can reliably prevent the overcurrent.

When an overvoltage occurs in the output circuit 33, the occurrence of the overvoltage is detected by the overvoltage detector 43, and this detection signal is detected by the photocoupler PC11 as P
The PW is fed back to the WM control circuit 39.
The M control circuit 39 can reduce the output voltage by reducing the duty ratio of the pulse signal to be output, and can avoid the overvoltage.

Further, when the output voltage of the output circuit fluctuates, this is detected by the output voltage detector 42, and the control circuit 46 controls the saturation and non-saturation of the mag-amplifier 41 to keep the output voltage constant. Is done.

In this way, in the multi-output power supply device 31 according to the second embodiment, the output circuits 33 to 35 have two systems of current detectors 44, respectively, as in the first embodiment. 45, control circuits 47, 48 are installed,
Since it is configured to limit the current (output power) flowing through the output circuits 33 to 35 based on the overcurrent detection signal of one of the systems, even if the current detector or the control circuit of one system fails. Even if it does, it is possible to reliably prevent the overcurrent, and it is possible to avoid troubles such as burning or damage of the circuit patterns of the output circuits 33 to 35 and the load side circuits connected to the output circuits 33 to 35. .

The multi-output power supply device of the present invention has been described above based on the illustrated embodiments. However, the present invention is not limited to these, and the configuration of each part is an arbitrary configuration having the same function. Can be replaced.

For example, in each of the above-described embodiments, the current detector and the overcurrent protection circuit of two systems are used to detect the occurrence of the overcurrent flowing in the output circuit and prevent it. The invention is not limited to this, and various modifications are possible.

For example, the first output limiting means and the second output limiting means respectively include an overcurrent protection circuit, an overvoltage protection circuit having an overcurrent protection function, an overheat protection circuit, a thermistor (for example, a PTC thermistor), It may have at least one selected from the group consisting of a posistor, a fuse, a three-terminal regulator (for example, a three-terminal regulator equipped with an overcurrent protection circuit), a circuit protector, a relay, a fuse resistor, and a temperature fuse resistor. it can.

The first output limiting means and the second output limiting means may be of the same type or of different types.

FIGS. 3A to 3F are circuit diagrams showing a modified example of the output limiting means. FIG. 10A shows an example in which the detection unit of one output limiting means is constituted by the current detector 61 and the other output limiting means is constituted by the fuse 62.

FIG. 10B shows an example in which the detection section of one output limiting means is constituted by the current detector 61, and the other output limiting means is constituted by the thermistor 63 or a posistor (not shown).

FIG. 10C shows an example in which the detection section of one output limiting means is composed of a current detector 61, and the other output limiting means is composed of a three-terminal regulator 64 equipped with an overcurrent protection circuit. . In this case, it is preferable to set the current value (power value) set on the three-terminal regulator 64 side smaller than the current value (power value) set on the current detector 61 side.

FIG. 10D shows an example in which the detector of one of the output limiting means is constituted by the current detector 61, and the other output limiting means is constituted by the circuit protector 65 or a breaker (not shown).

FIG. 10E shows an example in which the detector of one of the output limiting means is constituted by the current detector 61 and the other output limiting means is constituted by the fuse resistor 66.

FIG. 15F shows an example in which the detection section of one output limiting means is constituted by the current detector 61, and the other output limiting means is constituted by the temperature fuse resistor 67.

Even with the configuration shown in FIGS. 3 (a) to 3 (f), since the double output power limiting function is exerted, the output power (output current) is surely limited to the predetermined value. be able to.

In each of the above-described embodiments, the switching type multi-output power supply device has been described, but the present invention is not limited to this, and is also applied to a dropper type multi-output power supply device, for example. be able to.

[0107]

[0108]

As described above, according to the multi-output power supply device of the present invention, since it has the first output limiting means and the second output limiting means, the multi-output power supply device itself and its output are provided. It is possible to reliably protect the load side circuit (device) connected to the circuit. That is, the reliability of the multi-output power supply device is remarkably improved, and the safety is remarkably improved.

Further, even if the power is concentrated on the output circuit of one channel, the multi-output power supply device itself can be surely protected, so that it is assumed that the power is concentrated on the output circuit of one channel. Since it is not necessary to have the capacity, the device can be downsized and the cost can be reduced.

Further, even if power is concentrated on the output circuit of one channel, the circuit on the load side can be surely protected, so that the number of parts of the circuit on the load side can be reduced, downsizing and cost reduction can be achieved. be able to.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a configuration of a multi-output power supply device according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a modified example of the output limiting means.

FIG. 4 is a circuit diagram showing a configuration of a conventional multi-output power supply device.

[Explanation of symbols]

1 Multi-output power supply device 2 Input circuit 3-5 Output circuit 3a, 3b, 4a, 4b, 5a, 5b Output terminal 6 Rectification smoothing circuit 7 MOS-FET 8 Overcurrent detector 9 PWM control circuit 10 Rectification smoothing circuit 11 Overvoltage detection Unit 12 Output voltage detector 13, 14 Current detector 15, 22 Mag amplifier 16, 23 Rectification smoothing circuit 17, 24 Output voltage detector 18, 19, 25, 26 Current detector 20, 21, 27, 28 Control circuit 29, 30 Overcurrent Protection Circuit 31 Multiple Output Power Supply Device 32 Input Circuits 33-35 Output Circuits 33a, 33b Output Terminal 36 Rectification Smoothing Circuit 37 MOS-FET 38 Overcurrent Detector 39 PWM Control Circuit 40 Rectification Smoothing Circuit 41 Mag Amplifier 42 Output Voltage Detection Device 43 Overvoltage detector 44, 45 Current detector 46-48 Control circuit 51, 52 Overvoltage detector 61 Current detector 6 Fuse 63 Thermistor 64 3 terminal regulator 65 Circuit protector 66 Fuse resistance 67 Temperature fuse resistance E1, E11 AC power supply TR1, TR11 Transformer L1 Primary side coil L2 to L4 Secondary side coil PC1 to PC5, PC11 to PC13 Photo coupler 101 Multiple output Power supply device 102 Input circuits 103 to 105 Output circuits 103a, 103b, 104a, 104b, 105a,
105b Output terminal 106 Rectification smoothing circuit 107 MOS-FET 108 Overcurrent detector 109 PWM control circuit 110 Rectification smoothing circuit 111 Overvoltage detector 112 Output voltage detector 113 Mag amp 114 Rectification smoothing circuit 115 Output voltage detector 116 Mag amp 117 Rectification smoothing circuit 118 Output voltage detector 121-123 Overcurrent detector E101 AC power supply TR101 Transformer L101 Primary coil L102-L104 Secondary coil PC101, PC102 Photo coupler

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Claims (8)

(57) [Claims] 1. An output circuit having a transformer having a primary side coil and a plurality of secondary side coils, the output circuit having a rectifying means is connected to each of the secondary side coils to be independent of each of the output circuits. In the multi-output power supply device for obtaining the DC power described above, each of the output circuits of the plurality of channels is provided with a first detection unit for detecting an output current of the output circuit on the output side of the rectifying means, First output limiting means for limiting the output power to a first value and a second detector for detecting an output current of the output circuit are provided on the output side of the rectifying means, and the output power of the output circuit is A second output limiting means for limiting the second value different from the first value; 2. The first output limiting means limits the output power on the secondary side of the transformer, and the second output limiting means limits the output power on the primary side or the secondary side of the transformer. The multi-output power supply device according to claim 1, which is limited. 3. The multi-output power supply device according to claim 1, wherein the second value is set to be larger than the first value. 4. The first value is set to 101 to 500% of the maximum output power that can be constantly drawn, and the second value is 106 to 60 of the maximum output power that can be constantly drawn.
The multi-output power supply device according to claim 1, wherein the multi-output power supply device is set to 0%. 5. The first output limiting means is for protecting the multi-output power supply device itself, and the second output limiting means is for protecting a device connected to an output circuit. The multi-output power supply device according to claim 1, wherein the multi-output power supply device is a device. 6. The multi-output power supply according to claim 1, wherein the first output limiting means of the first output limiting means and the second output limiting means operates preferentially. apparatus. 7. The first output limiting means and the second output limiting means.
The output limiting means of are respectively an overcurrent protection circuit, an overvoltage protection circuit having an overcurrent protection function, an overheat protection circuit, a thermistor, a posistor, a fuse, a three-terminal regulator,
At least one selected from the group consisting of circuit protectors, relays, fuse resistors and thermal fuse resistors
7. The multi-output power supply device according to claim 1, which has one. 8. A transformer having a primary side coil and a plurality of secondary side coils, wherein a pulse voltage is applied to the primary side coil and an output circuit having a rectifying means is provided for each of the two output circuits.
In a multi-output power supply device that is connected to each secondary coil to obtain independent DC power from each output circuit, a switching unit that applies a DC voltage to the primary coil in a pulsed manner, and a pulse signal to the switching unit. And a pulse width control means for controlling the duty ratio of the pulse signal, wherein each of the output circuits has a mag-amp connected to the secondary coil and an output current of the output circuit. First output control means for outputting a control signal to the mag-amplifier so as to limit the output power of the output circuit to a first value by providing a first detection section for detecting on the output side of the rectification means; A second detector for detecting the output current of the output circuit is provided on the output side of the rectifying means, and the output power of the output circuit is
A second output control means for outputting a control signal to the mag-amplifier so as to limit it to a second value larger than the first value.