JPH0844438A - Power supply device - Google Patents

Abstract

PURPOSE:To hold voltage impressed to both the ends of a load at a fixed level at the time of parallel operation and to suppress the drop of the voltage at the time of interrupting an output from a power supply body. CONSTITUTION:Voltage Vo impressed to both the ends of the load 3 is detected by a voltage detecting circuit 6. Variable command voltage Vr is impressed from a voltage correcting circuit 8 to the power supply body 1 based upon the detected result. When the voltage Vo is dropped, the voltage Vr matched with the drop of the voltage Vo is superposed to the reference voltage of a 1st error amplifier 13. Thereby the body 1 having low output voltage V1 is waited in a no-load state. Even when another power supply body stops operating, the dropped level of the ouput voltage V1 is immediately compensated. Consequently the voltage Vo of the load 3 can be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device capable of parallel redundant operation by a plurality of power supply main bodies.

[0002]

2. Description of the Related Art FIG. 7 shows a circuit configuration diagram when two general power source bodies 1 and 2 are operated in parallel. In FIG. 7, the power source bodies 1 and 2 having the same configuration have a feedback loop. A built-in DC-DC converter (not shown) is provided, and predetermined DC output voltages V1, V2 are output from the respective output terminals + V, -V.
Are supplied to the load 3. In addition, in each power supply main body 1 and 2,
A pair of remote sensing terminals + that correct the voltage drop of the output voltage line between the output terminals + V, -V and the load 3.
S, -S are provided. Remote sensing terminal + S,
The voltage between −S is applied as a detection voltage to one input terminal of an error amplifier (not shown) and compared with a reference voltage applied to the other input terminal of the error amplifier. And
Based on the output from this error amplifier, the power supplies 1 and 2 are controlled so that the voltage between the remote sensing terminals + S and -S is kept constant. On the other hand, in parallel redundant operation in which a plurality of such power supply main bodies 1 and 2 are connected in parallel, if the output from one power supply main body 1 is stopped for some reason, the current does not flow into this power supply main body 1. Backflow prevention diodes 4 and 5 are inserted and connected to the output voltage lines of the power supply bodies 1 and 2, and the diodes 4 and 5 prevent the load 3 and other normal power supply bodies 2 from being affected. .

[0003]

In the above-mentioned conventional parallel redundant operation, the remote sensing lines connected to the remote sensing terminals + S and -S are connected to the anode sides of the diodes 4 and 5 as shown by the solid lines in FIG. And a method of connecting the remote sensing line to the load 3 side as shown by the broken line in FIG. 7. But in the method of
Since the output voltages V1 and V2 are controlled to be constant,
The voltage Vo across the load 3 has a value lowered by the voltage drops VF1 and VF2 generated in the diodes 4 and 5, respectively. Moreover, since the voltage drops VF1 and VF2 of the diodes 4 and 5 greatly vary depending on the output currents I1 and I2 as shown in the graph of FIG. 8, there is a problem that the output accuracy for the load 3 is poor.

On the other hand, in the method 1, the voltage V across the load 3 is
Although o can be made constant, if the output currents I1 and I2 from the respective power supply bodies 1 and 2 are not equally shared, as shown in the graph of FIG. Power is supplied to the power supply main body 1, the oscillation of the power supply main body 1 having a low output voltage V1 is stopped, and the output voltage V1 becomes zero. Moreover, in this state, when the power supply of the power supply main body 2 having a high output voltage V2 is cut off, a large voltage drop indicated by the diagonal line in FIG. 9 occurs until the power supply main body 1 having a low output voltage V1 rises. The influence on the load 3 becomes large.

By the way, the remote sensing terminal + S,
In power supply main units 1 and 2 not equipped with -S, output terminal +
The output voltages V1 and V2 between V and -V are detected, the detected voltage and the reference voltage are error-amplified by an error amplifier (not shown), and the output terminal + is output based on the output from the error amplifier.
Control is performed so that the output voltages V1 and V2 between V and -V are kept constant. However, in this case, the output voltage V
Since the control to keep 1 and V2 constant is performed, the same problem as in the above method occurs and the output accuracy for the load 3 deteriorates.

In order to solve each of these problems, Japanese Patent Laid-Open No. 6-105464 discloses a voltage drop in a backflow prevention diode, and based on this detection result, DC /
There is disclosed a power supply circuit in which a correction resistor is connected in parallel to a part of an output voltage detection resistor of a DC converter so as not to be affected by a voltage drop of a backflow prevention diode. However, in such a method, the connection of the correction resistor is switched according to the change in the voltage across the backflow prevention diode.
When the output is cut off, a delay occurs and a large voltage drop with respect to the load 3 cannot be quickly corrected.

As described above, according to the conventional method, the power supply main body 2
If it is attempted to prevent the voltage across the load 3 from dropping when the output is cut off, the voltage across the load 3 cannot be kept constant even after the output of the power supply main body 2 is cut off, and conversely the output of the power supply main body 2 is cut off. If the voltage across the load 3 is to be kept constant after that, there is a problem that a large voltage drop with respect to the load 3 cannot be quickly corrected when the output of the power supply body 2 is cut off.

In view of the above problems, therefore, the present invention does not stop the oscillation of each power source main body during parallel operation, and responds promptly when the output of one power source main body is shut off to minimize the influence on the load. It is an object of the present invention to provide a power supply device that can suppress the output voltage of one power supply main body and can keep the voltage across the load constant even after the output of one power supply main body is cut off.

[0009]

According to a first aspect of the present invention, there is provided a power supply device which detects a direct current output voltage between output terminals, and amplifies the detected voltage and a reference voltage by a first error amplifier. For preventing backflow between the output terminals of each power source body and the load by connecting in parallel a plurality of power source bodies for controlling the DC output voltage between the output terminals to be kept constant based on the output from the error amplifier In a power supply device in which a diode is inserted and connected, a voltage detection circuit that detects the voltage across the load is connected to the cathode of the backflow prevention diode, and the value is continuously measured according to the detection result from the voltage detection circuit. A voltage correction circuit that supplies a variable command voltage that is variable to one input terminal of the first error amplifier is provided.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a second aspect is provided in which the detection signal from the cathode of the detection backflow prevention diode and the reference voltage from the reference power source are error-amplified. And an anode connected to the output terminal of the second error amplifier, and is connected to one input terminal of the first error amplifier only when the detection signal from the cathode of the backflow prevention diode is lower than a predetermined value. The voltage correction circuit is configured by a diode that injects the variable command voltage to raise a DC output voltage between the output terminals.

According to another aspect of the power supply device of the present invention, the voltage between the remote sensing terminals is detected, and the detected voltage and the reference voltage are error-amplified by the first error amplifier. A plurality of power supply main bodies for controlling so that the voltage between the remote sensing terminals is kept constant based on the output are connected in parallel, and a backflow prevention diode is inserted and connected between the output terminal of each power supply main body and the load. In the power supply device, the remote sensing terminal is connected to the load side, and a voltage detection circuit that detects the voltage across the backflow prevention diode, and its value continuously changes according to the detection result from the voltage detection circuit. And a voltage correction circuit for supplying a variable command voltage that is variable to one input terminal of the first error amplifier.

Further, in addition to the structure of claim 3, the power supply device of claim 4 further comprises a second error amplifier for error-amplifying each detection signal from the anode and the cathode of the backflow prevention diode. An anode is connected to the output terminal of the second error amplifier, and the variable command voltage is injected into one input terminal of the first error amplifier only when the detection signal from the anode of the backflow prevention diode is lower than a predetermined value. Then, the voltage correction circuit is configured by a diode that raises the DC output voltage between the output terminals.

[0013]

According to the structure of the present invention, the voltage detecting circuit detects the voltage across the load, and the variable command voltage corresponding to the variation of the voltage across the load is supplied from the voltage correcting circuit to one of the first error amplifiers of the power supply body. By supplying to the input terminal side of, without stopping the oscillation of each power supply body in parallel operation,
It is possible to stabilize the voltage across the load. In this case, the power supply unit with a low output voltage is waiting in the no-load state, so the power supply of the power supply unit with a high output voltage is cut off,
Even if the remaining output current from the power supply unit flows to the load via the backflow prevention diode, the value of the variable command voltage from the voltage correction circuit changes continuously according to the detection result from the voltage detection circuit. Therefore, the voltage correction circuit immediately outputs the variable command voltage for correcting the decrease in the output voltage of the load. Therefore, when the output of the power supply main body is cut off, it is possible to promptly respond and to minimize the influence on the load. Further, even after the output of the power supply main body is cut off, the voltage across the load is kept constant by the voltage detection circuit and the voltage correction circuit.

According to the second aspect of the present invention, when the terminal voltage of the load is higher than the predetermined value, the current from the main body of the power source is prevented from flowing into the second error amplifier side, and the power source by the voltage correction circuit is blocked. The influence on the main body can be suppressed to the necessary minimum.

According to the third aspect of the present invention, the voltage detection circuit detects the output voltage of the power supply unit with reference to the voltage across the load side, and the voltage correction circuit compares the variable command voltage corresponding to the fluctuation of the output voltage with the comparator. In order to supply power to the input terminal side of the power supply, the variable command voltage according to the output voltage is supplied from each voltage correction circuit to the power supply unit during parallel operation by multiple power supply units, and the oscillation of the power supply unit with low output voltage is stopped. Disappear.
Moreover, even if the power supply from the power supply main body with a high output voltage is cut off during parallel operation, the power supply from the other side is instantaneously switched. Further, since the remote sensing terminal is connected to the load side, the voltage across the load can be kept constant even after the output of the power supply body is cut off.

Further, according to the structure of claim 4, when the terminal voltage of the load is higher than a predetermined value, the power supply unit is connected to the second side.
It is possible to prevent the current from flowing into the error amplifier side, and to suppress the influence of the voltage correction circuit on the power supply main body to the necessary minimum.

[0017]

Embodiments of the present invention will be described below with reference to FIGS. In each of these drawings, the same parts as those in FIG. 7 described above are designated by the same reference numerals, and detailed description of the common parts will be omitted.

1 and 2 show a first embodiment of the present invention corresponding to the first and second aspects. FIG. 1 shows a schematic configuration of a power supply device having two power supply main bodies 1 and 2. In the figure, reference numerals 1 and 2 denote power supply main bodies having the same configuration, and 3 denotes a load common to the power supply main bodies 1 and 2. , Each of the power supply bodies 1 and 2 has an output terminal + V, -V, and an output terminal +
A voltage variable terminal P capable of externally varying the output voltages V1 and V2 between V and -V is provided. On the other hand, 6 and 7 are voltage detection circuits for detecting the voltage Vo across the load 3,
The voltage detection circuit 6 provided on the power supply body 1 side is connected to the cathode of the diode 4, and the voltage detection circuit 7 provided on the power supply body 2 side is connected to the cathode of the diode 5. Further, 8 and 9 are voltage variable terminals P of the power supply bodies 1 and 2.
It is a voltage correction circuit of the same configuration connected to
The variable command voltage Vr, which is continuously variable according to the detection results from the voltage detection circuits 6 and 7, is used as a first error amplifier to be described later.
It is supplied to one of the 13 input terminals.

Next, based on FIG. 2, the circuit configuration of the power supply main body 1 side will be described in detail. In the power supply body 1, 11,
Reference numeral 12 is a resistor for voltage division as an output voltage detecting circuit connected in series between the output terminals + V and -V, and the connection point of the resistors 11 and 12 is connected to the inverting input terminal of the first error amplifier 13. . Further, 14 is a reference voltage generating circuit for supplying a reference voltage to the non-inverting input terminal of the first error amplifier 13, which is
Connect resistors 16 and 17 for voltage division to both ends of the reference power supply 15
The connection point of 16 and 17 is connected to the non-inverting input terminal of the first error amplifier 13. Further, this first error amplifier
Thirteen non-inverting input terminals are connected to the voltage variable terminal P. The first error amplifier 13 error-amplifies the detection voltage obtained by dividing the output voltage V1 between the output terminals + V and -V by the resistors 11 and 12, and the reference voltage from the reference voltage generation circuit 14, and outputs the amplified voltage. The output is output to the control circuit 18. The control circuit 18 is the first error amplifier.
Based on the output from 13, the DC / DC converter (not shown) is controlled so as to keep the output voltage V1 between the output terminals + V and -V constant.

On the other hand, the voltage detection circuit 6 is constituted by connecting a pair of voltage dividing resistors 23 and 24 between the cathode of the backflow prevention diode 4 and the output terminal -V. In addition, the voltage correction circuit 8 connects the connection point of the resistors 23 and 24 to the inverting input terminal, while connecting the reference power supply 31 that outputs the reference voltage VREF to the non-inverting input terminal, and to connect the cathode of the backflow prevention diode 4 to the cathode. The second error amplifier 25 for error-amplifying the detection signal VK from the reference voltage VREF and the reference voltage VREF from the reference power source 31, and the anode of the backflow prevention diode 4 are connected to the anode of the output terminal of the second error amplifier 25. Output voltage V1 by injecting the variable command voltage Vr from the output terminal of the second error amplifier 25 to the non-inverted input terminal of the first error amplifier 13 only when the detection signal VK is lower than a predetermined value, that is, the reference voltage VREF.
And a diode 27 for raising the voltage. Further, a phase compensation circuit composed of a series circuit of a capacitor 32 and a resistor 33 is connected between the inverting input terminal and the output terminal of the second error amplifier 25. Although not shown in detail, the circuit configuration on the power supply main body 2 side is exactly the same as that shown in FIG.

Next, the operation of each structure shown in FIGS. 1 and 2 will be described. The power supply bodies 1 and 2 are connected in parallel to a common load 3, but the power supply bodies 1 and 2 output voltage V1 or output voltage V1 between their own output terminals + V and -V.
The control is performed so that 2 is kept constant. Explaining this with respect to the power supply main body 1, the output voltage V1 between the output terminals + V and -V is divided by the voltage dividing resistors 11 and 12, and
While being applied as a detection voltage to the inverting input terminal of the error amplifier 13, the reference voltage from the reference voltage generating circuit 14 is applied to the non-inverting input terminal of the first error amplifier 13. First
Error amplifier 13 error-amplifies the detected voltage and the reference voltage VREF, and the control circuit 18 controls the output voltage V1 between the output terminals + V and -V on the basis of the output from the first error amplifier 13. I do. The same applies to the power supply main body 2.

On the other hand, the voltage detection circuit 6 divides the cathode voltage of the backflow prevention diode 4 by the resistors 23 and 24, and outputs it as the detection signal VK to the inverting input terminal of the second error amplifier 25 constituting the voltage correction circuit 8. Supply. Here, the second error amplifier 25 uses the stable reference voltage VREF from the reference power source 31.
And the detection signal VK are error-amplified, the voltage level of the output terminal of the second error amplifier 25 is linear and continuous according to the cathode voltage of the backflow prevention diode 4, that is, the voltage Vo across the load 3. Fluctuate.

At this time, the terminal voltage Vo of the load 3 is high,
When the voltage level of the output terminal of the second error amplifier 25 is lower than the reference voltage from the reference voltage generation circuit 14, the diode 27 of the voltage correction circuit 8 becomes non-conducting state and the inversion of the first error amplifier 13 occurs. The reference voltage of the reference voltage generation circuit 14 is directly applied to the input terminal. On the other hand, when the terminal voltage Vo of the load 3 decreases and the voltage level of the output terminal of the second error amplifier 25 becomes higher than the reference voltage from the reference voltage generating circuit 14, the diode 27 is turned on this time. , Load 3
The variable command voltage Vr corresponding to the variation of the terminal voltage Vo of
It is superimposed on the reference voltage of the reference voltage generation circuit 14. Therefore, the control circuit 18 of the power supply main body 1 performs control so as to increase the output voltage V1 only when the diode 27 of the voltage correction circuit 8 becomes conductive.

By the way, in the case of a power supply device which does not have the voltage detection circuit 6 and the voltage correction circuit 8, each of the power supply bodies 1 and 2
Performs control to keep the output voltage Vo between its own output terminals + V and -V constant, the voltage Vo across the load 3 fluctuates due to the voltage drops VF1 and VF2 of the diodes 4 and 5, and the output current I1. , I2 decreases as I2 increases. However, when the voltage detection circuit 6 and the voltage correction circuit 8 are provided in each of the power supply bodies 1 and 2 as in the present embodiment, as the voltage Vo across the load 3 decreases, the voltage correction circuit 8 changes the voltage variable terminal. The variable command voltage Vr output to P rises so that the variation of the voltage Vo across the load 3 is corrected,
The output voltages V1 and V2 between the output terminals + V and -V rise. Therefore, the voltage drop VF1, of the diodes 4, 5
It is possible to correct VF2 and keep the voltage Vo across the load 3 constant.

The output voltage V between the output terminals + V and -V
1 and V2 are different for each of the power supply main bodies 1 and 2, but if the output voltage V2 of the power supply main body 2 is higher than the output voltage V1 of the power supply main body 1, the power supply main body having a high output voltage V2. 2 through diode 5 to load 3 output current I2
Is supplied. On the other hand, the power supply body 1 having a low output voltage V1
Does not supply the output current I2 unless the voltage Vo across the load 3 becomes lower than the output voltage V1 by the voltage drop VF1 of the diode 4. However, in this embodiment, the voltage detection circuit 6 and the voltage correction circuit 8 correct the voltage drops VF1 and VF2 of the diodes 4 and 5 to keep the voltage Vo across the load 3 constant, so that the output voltage V1 It is possible to make the power supply main body 1 having a low power consumption stand by in an unloaded state without supplying the output current I2. Therefore,
In this state, even if the power supply of the power supply main body 2 having a large output voltage V2 is cut off, the voltage detection circuit 6 immediately detects a decrease in the output voltage Vo of the load 3 due to the voltage drop VF1 of the diode 4. Since the voltage correction circuit 8 immediately outputs the variable command voltage Vr for correcting the amount of decrease in the output voltage Vo of the load 3, the output voltage Vo of the load 3 does not drop significantly and the remaining power source body 1 continues to load the load. 3 is controlled to be maintained at a predetermined terminal voltage Vo.

As described above, in the power supply device of this embodiment, the voltage detecting circuits 6 and 7 for detecting the voltage Vo across the load 3 are connected to the cathodes of the backflow preventing diodes 4 and 5, and the voltage detecting circuits 6 and 7 are connected. A voltage correction circuit for supplying a variable command voltage Vr whose value is continuously variable according to the detection result from 7 to one input terminal of the first error amplifier 13 is provided. 6 and 7, the voltage Vo across the load 3 is detected, and the variable command voltage Vr commensurate with the variation in the voltage Vo across the load 3 is supplied from the voltage correction circuits 8 and 9 to the first error amplifier 13 of the power supply bodies 1 and 2. By supplying the voltage to one input terminal side, it is possible to stabilize the voltage Vo across the load 3 without stopping the oscillation of the power supply bodies 1 and 2 in parallel operation. In this case, the power supply main body 1 having a low output voltage V1 is standing by in an unloaded state, so that when the power supply of the power supply main body 2 having a high output voltage V2 is cut off, the output current I1 from the power supply main body 1 passes through the diode 4. Load 3
Flow into the variable command voltage Vr from the voltage correction circuit 8.
Since its value continuously changes according to the detection result from the voltage detection circuit 6, the voltage correction circuit 8 immediately loads the load 3
The variable command voltage Vr that corrects the decrease in the output voltage Vo is output. Therefore, there is no delay caused by the switching of the correction resistance as in the conventional case, and it is possible to quickly respond to the output cutoff of the power supply main body 2 and minimize the influence on the load 3. Further, even after the output of the power supply main body 2 is cut off, the voltage Vo across the load can be kept constant by the voltage detection circuit 6 and the voltage correction circuit 8.

Further, in this embodiment, the second error amplifier 25 for error-amplifying the detection signal VK from the cathodes of the backflow preventing diodes 4 and 5 and the reference voltage VREF from the reference power supply 31.
An anode is connected to the output terminal of the second error amplifier 25, and only when one of the first error amplifier 13 has a detection signal VK lower than a predetermined value from the cathodes of the backflow preventing diodes 4 and 5. It is characterized in that the voltage correction circuits 8 and 9 are constituted by a diode 27 which injects the variable command voltage Vr into the input terminal and raises the DC output voltages V1 and V2 between the output terminals + V and -V. In this case, in addition to the above-described actions and effects, when the terminal voltage Vo of the load 3 is higher than a predetermined value, the inflow of current from the power supply bodies 1 and 2 to the second error amplifier 25 side is blocked, The influence of the voltage correction circuits 8 and 9 on the power supply bodies 1 and 2 can be suppressed to the necessary minimum.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted to avoid duplication. In this embodiment, the voltage correction circuits 8 and 9 of the power supply bodies 1 and 2 are used.
In addition, a common voltage detection circuit 6 that outputs a detection signal VK from the cathodes of the diodes 4 and 5 is provided. Further, the voltage correction circuits 8 and 9 include a common reference power supply 31.
The operation of this embodiment is exactly the same as that of the first embodiment, but the voltage detection circuit 6 and the reference power supply 31 are commonly used, so that the circuit configuration can be simplified.

In the first and second embodiments,
The reference voltage VREF of the reference power supply 31 may be supplied from either one of the power supply bodies 1 and 2. For example,
By using the reference power supply 15 of the reference voltage generation circuit 14, the reference power supply 31 can be omitted and the circuit configuration can be further simplified. Further, although the variable command voltage Vr for increasing the reference voltage is supplied to the non-inverting input terminal of the first error amplifier 13, the variable command voltage is applied to the inverting input terminal to which the detection voltage from the resistors 11 and 12 is applied. The voltage Vr may be supplied. In this case, when the output voltage Vo of the load 3 drops, it is necessary to supply the variable command voltage Vr so as to drop the detection voltage from the connection point of the resistors 11 and 12. Further, since the voltage detection circuits 6 and 7 are composed of the pair of resistors 23 and 24, the value of the output voltage Vo of the load 3 for injecting the variable command voltage Vr into the power supply body 1 side can be arbitrarily and easily changed by this. You can

Another advantage of the first and second embodiments is that the power supply bodies 1 and 2 which do not have the remote sensing terminals + S and -S as shown in FIG. The object of the invention is to be achieved. Also, the power supply main bodies 1 and 2 equipped with the remote sensing terminals + S and -S
Even if the remote sensing wire is output terminal + V,-
If connected to V respectively, the power supply bodies 1 and 2 will output terminals + V,
Since the control is performed so as to keep the output voltage Vo between −V constant, the same operation and effect as those of the above-described respective embodiments can be obtained. That is, the circuit configurations of the first and second embodiments can be applied to any of the power supply bodies 1 and 2 regardless of the presence or absence of the remote sensing terminals + S and -S.

Next, a third embodiment of the present invention will be described with reference to FIGS.
It will be explained based on. In FIG. 4 showing a schematic configuration of a power supply device, reference numerals 1 and 2 denote power supply bodies having the same configuration, 3 denotes a load common to the power supply bodies 1 and 2, and a remote sensing terminal
S and -S are connected to the load 3 side which is the cathode side of the backflow preventing diodes 4 and 5. In addition to the output terminals + V and -V and the remote sensing terminals + S and -S, the power supply bodies 1 and 2 have an output voltage V between the output terminals + V and -V.
There is provided a voltage variable terminal P capable of changing 1 and V2 from the outside. On the other hand, 6 and 7 are voltage detection circuits for detecting the voltages across the anode and cathode of the diodes 4 and 5, respectively. Further, reference numerals 8 and 9 denote voltage correction circuits having the same configuration, which are connected to the voltage variable terminals P of the power supply bodies 1 and 2, and are continuously variable according to the detection results from the voltage detection circuits 6 and 7. The variable command voltage Vr is supplied to one input terminal of a first error amplifier 13 described later.

Next, with reference to FIG. 5, the circuit configuration on the power supply main body 1 side will be described in detail. In the power supply body 1, 11,
12 is a resistor for voltage division as a load end voltage detection circuit connected in series between the remote sensing terminals + S and -S,
The connection point of the resistors 11 and 12 is connected to the inverting input terminal of the first error amplifier 13. Further, 14 is a reference voltage generating circuit for supplying a reference voltage to the non-inverting input terminal of the first error amplifier 13, and this is a voltage dividing resistor 16 at both ends of a reference power source 15.
17 is connected, and the connection point of the resistors 16 and 17 is connected to the first error amplifier 13
It is configured by connecting to the non-inverting input terminal of. Further, the non-inverting input terminal of the first error amplifier 13 is the voltage variable terminal P
Connected to. The first error amplifier 13 error-amplifies the detection voltage obtained by dividing the voltage Vo between the remote sensing terminals + S and -S by the resistors 11 and 12, and the reference voltage from the reference voltage generation circuit 14, The output is output to the control circuit 18. Based on the output from the first error amplifier 13, the control circuit 18 controls a DC / DC converter (not shown) so as to keep the voltage Vo across the load 3 to which the remote sensing terminals + S and -S are connected constant. .

On the other hand, the voltage detection circuit 6 is constructed by connecting a pair of resistors 21 and 22 for voltage division and resistors 23 and 24 to the cathode and anode of the backflow prevention diode 4. In the voltage correction circuit 8, the connection points of the resistors 21 and 22 are connected to the inverting input terminal, the connection points of the resistors 23 and 24 are connected to the non-inverting input terminal, and the anode and cathode of the backflow prevention diode 4 are connected. Via a second error amplifier 25 for error-amplifying the respective detection signals VA and VK from, a resistor 26 for generating a variable command voltage Vr connected to the output terminal of the second error amplifier 25, and a resistor 26. And an anode is connected to the output terminal of the second error amplifier 25, and the first detection signal VA from the anode of the backflow prevention diode 4 is lower than a predetermined value.
Of the error amplifier 13 and the diode 27 for injecting the variable command voltage Vr into the non-inverting input terminal. Although not shown in detail, the circuit configuration on the power supply main body 2 side is exactly the same as that shown in FIG.

Next, the operation of the above configuration will be described with reference to the graph of FIG. Each power supply body 1, 2
Since the remote sensing lines from the remote sensing terminals + S and -S are connected to the load 3 side, control is performed so as to keep the voltage Vo across the load 3 constant. That is, the voltage Vo across the load 3 is divided by the voltage dividing resistors 11 and 12 and applied to the inverting input terminal of the first error amplifier 13 as a detection voltage, and at the same time, the reference voltage generating circuit.
The reference voltage from 14 is applied to the non-inverting input terminal of the first error amplifier 13. The first error amplifier 13 error-amplifies the detected voltage and the reference voltage, and the control circuit 18 performs control to stabilize the voltage Vo across the load 3 based on the output from the first error amplifier 13.

On the other hand, the voltage detection circuit 6 outputs the anode voltage and the cathode voltage of the backflow prevention diode 4 to the resistors 21,
The voltage is divided by 22 and resistors 23 and 24, and the detection signal V is input to each input terminal of the second error amplifier 25 that constitutes the voltage correction circuit 8.
Although supplied as A and VK, the cathode voltage of the backflow prevention diode 4 on the load 3 side is kept substantially constant by the control of the power supply bodies 1 and 2, so that the output terminal of the second error amplifier 25 is backflowed. The voltage level thereof varies linearly and continuously according to the anode voltage of the prevention diode 4, that is, the output voltage V1 of each power supply body 1. At this time, when the output voltage V1 of the power supply main body 1 rises and the voltage level of the output terminal of the second error amplifier 25 becomes lower than the reference voltage from the reference voltage generation circuit 14, the diode 27 of the voltage correction circuit 8 is generated.
Becomes non-conductive, and the reference voltage of the reference voltage generating circuit 14 is directly applied to the inverting input terminal of the first error amplifier 13. On the other hand, when the output voltage V1 of the power supply body 1 decreases and the voltage level of the output terminal of the second error amplifier 25 becomes higher than the reference voltage from the reference voltage generation circuit 14, the diode 27 is turned on this time. Then, the variable command voltage Vr corresponding to the variation of the output voltage V1 is superimposed on the reference voltage of the reference voltage generation circuit 14. Therefore, the control circuit 18 of the power supply main body 1
Controls to increase the output voltage V1 only when the diode 27 of the voltage correction circuit 8 is turned on.

In the case of a power supply device which does not have the voltage detection circuit 6 and the voltage correction circuit 8, if the remote sensing terminals + S and -S are connected to the load 3 side, the output currents I1 and I2 of the power supply bodies 1 and 2 will be equalized. Unless shared, the output voltage V2
Power is supplied from the power supply main body 2 having a high output voltage to the load 3, and the oscillation of the power supply main body 1 having a low output voltage V1 is stopped. However, when the voltage detection circuit 6 and the voltage correction circuit 8 are provided in each of the power supply bodies 1 and 2 as in this embodiment, the output current I
Even if 1 and I2 are not evenly shared, as shown in the graph of FIG. 6, in the power supply main body 1 having a low output voltage V1, the output voltage V1 rises due to the variable command voltage Vr from the voltage correction circuit 8 and oscillation occurs. Output terminal + V, without stopping
A predetermined output voltage V1 is generated at -V. Therefore, in this state, the power supply main body 2 having a large output voltage V2
Even if the power supply is cut off, the power supply main body 1 stands by in a state where the oscillation is not stopped. Therefore, the output voltage V1 is slightly decreased immediately after the cutoff, and the output voltage V1 is decreased immediately thereafter. Is detected by the voltage detection circuit 6, and the voltage correction circuit 8 immediately outputs the variable command voltage Vr for correcting the decrease in the output voltage V1. In the end, there is no large drop in the output voltage V1 and the remaining power source body 1 continues. Control for maintaining the load 3 at a predetermined terminal voltage Vo is performed.

As described above, the power supply device according to the present embodiment detects the voltage between the remote sensing terminals + S and -S and outputs the detected voltage and the reference voltage to the first error amplifier according to the third aspect. A plurality of power supply main bodies 1 and 2 that perform error amplification at 13 and control so as to keep the voltage between the remote sensing terminals + S and -S constant based on the output from the first error amplifier 13.
Are connected in parallel, and the output terminals + V,
In the power supply device in which the backflow prevention diodes 4 and 5 are inserted and connected between -V and the load 3, the remote sensing terminals + S and -S are connected to the load 3 side and the backflow prevention diodes 4 and 5 are connected. The voltage detection circuits 6 and 7 for detecting the both-end voltage and the variable command voltage Vr which continuously changes according to the detection results from the voltage detection circuits 6 and 7 are supplied to one input terminal of the first error amplifier 13. Voltage correction circuit 8,
9 and 9 are provided. That is, the voltage detection circuit 6,
7, the output voltages V1 and V2 are detected with reference to the load-side voltage Vo on the load 3 side, and the variable command voltage Vr corresponding to this is detected from the voltage correction circuits 8 and 9 according to the variation of the output voltages V1 and V2. By supplying the error amplifier 13 to the one input terminal side of the error amplifier 13, parallel operation for stabilizing the voltage Vo across the load 3 can be performed without stopping the oscillation of the power supply body 1 having a low output voltage V1. . Moreover, since the value of the variable command voltage Vr from the voltage correction circuits 8 and 9 is continuously variable according to the detection result from the voltage detection circuits 6 and 7, there is a delay due to the switching of the correction resistors as in the conventional case. There is no occurrence of
It is possible to minimize the influence on the load 3. At this time, the terminal voltage Vo of the load 3 can be kept constant from the remaining power supply body 1.

Further, the present embodiment corresponds to the fourth aspect, and a second error amplifier 25 for error-amplifying the detection signals VA and VK from the anode and cathode of the backflow preventing diodes 4 and 5, respectively. The anode is connected to the output terminal of the second error amplifier 25, and the variable command is given to one input terminal of the first error amplifier 13 only when the detection signal VA from the anodes of the backflow prevention diodes 4 and 5 is lower than a predetermined value. The voltage correction circuits 8 and 9 are configured by the diode 27 that injects the voltage Vr. Therefore, in this case, the above-mentioned claim 3
In addition to the action and effect of the
When 1 and V2 are higher than a predetermined value, the flow of current from the power supply bodies 1 and 2 to the second error amplifier 25 side is blocked, and the voltage correction circuits 8 and 9 affect the power supply bodies 1 and 2. Can be minimized.

In this embodiment, the variable command voltage Vr for raising the reference voltage is supplied to the non-inverting input terminal of the first error amplifier 13, but the detection voltage from the resistors 11 and 12 is applied. The variable command voltage Vr may be supplied to the inverting input terminal. In this case, it is necessary to supply the variable command voltage Vr so that the detection voltage from the connection point of the resistors 11 and 12 is reduced when the output voltage V1 is reduced. Further, as an effect of the embodiment, since the voltage detection circuit is provided with the pair of voltage dividing resistors 21 and 22 and the resistors 23 and 24 at both ends of the backflow prevention diode 4, the variable command voltage Vr is thereby supplied. The value of the output voltage V1 injected to the first side can be arbitrarily and easily changed. In this case, in consideration of the voltage drop VF1 of the backflow prevention diode 4, when the output voltage V1 becomes lower than the value obtained by adding the cathode voltage of the backflow prevention diode 4 and the voltage drop VF1, the variable command voltage Vr is set. It is preferable to set each resistor 21 to 24 so as to inject.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the gist of the present invention.

[0041]

According to the power supply device of the present invention, the DC output voltage between the output terminals is detected, and the detected voltage and the reference voltage are error-amplified by the first error amplifier. Based on the output of the plurality of power source main body connected in parallel to control to maintain a constant DC output voltage between the output terminals,
In a power supply device in which a backflow prevention diode is inserted and connected between the output terminal of each power supply main body and a load, a voltage detection circuit that detects the voltage across the load is connected to the cathode of the backflow prevention diode. , A voltage correction circuit that supplies a variable command voltage whose value varies continuously according to the detection result from the voltage detection circuit to one input terminal of the first error amplifier, Without stopping the oscillation of each power supply body during operation,
It is possible to promptly respond to the output cutoff of one power supply main body to minimize the influence on the load, and further to keep the voltage across the load constant even after the output cutoff of the one power supply main body.

According to a second aspect of the present invention, there is provided a second error amplifier for error-amplifying the detection signal from the cathode of the backflow prevention diode and the reference voltage from the reference power source, and the second error amplifier. The output terminal of the first error amplifier is injected with the variable command voltage only when the anode is connected to the output terminal of the output terminal and the detection signal from the cathode of the backflow prevention diode is lower than a predetermined value. Since the voltage correction circuit is composed of a diode that raises the DC output voltage between the power supply units, it does not stop the oscillation of each power supply unit during parallel operation, and responds quickly when the output of one power supply unit is shut off. As a result, the effect on the load can be minimized, and the voltage across the load can be kept constant even after the output of one of the power supplies is cut off. The impact of by the correction circuit to power the body can be kept to a necessary minimum.

Further, in the power supply device according to the third aspect, the voltage between the remote sensing terminals is detected, the detected voltage and the reference voltage are error-amplified by the first error amplifier, and the voltage from the first error amplifier is detected. A plurality of power supply main bodies for controlling so that the voltage between the remote sensing terminals is kept constant based on the output are connected in parallel, and a backflow prevention diode is inserted and connected between the output terminal of each power supply main body and the load. In the power supply device, the remote sensing terminal is connected to the load side, and a voltage detection circuit that detects the voltage across the backflow prevention diode, and its value continuously changes according to the detection result from the voltage detection circuit. Since a voltage correction circuit that supplies a variable command voltage that is variable to one input terminal of the first error amplifier is provided, oscillation of each power supply body during parallel operation is achieved. It is possible to minimize the influence on the load without interrupting the output of one of the power supplies, and to quickly respond to the output of one of the power supplies. Can be kept constant.

According to a fourth aspect of the power supply device of the present invention, a second error amplifier for error-amplifying each detection signal from the anode and the cathode of the backflow prevention diode, and an anode at the output terminal of the second error amplifier. Is connected and the detection signal from the anode of the backflow prevention diode is lower than a predetermined value, the variable command voltage is injected into one input terminal of the first error amplifier to output a DC output voltage between the output terminals. Since the voltage correction circuit is configured with a diode that raises the voltage, it does not stop the oscillation of each power supply main unit during parallel operation, and it responds quickly to the load when the output of one power supply main unit is cut off. Can be minimized, and the voltage across the load can be kept constant even after the output of one of the power supplies is cut off.
It is possible to minimize the influence of the voltage correction circuit on the power supply main body.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a power supply device showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a main part of the same as above.

FIG. 3 is a circuit configuration diagram of a power supply device showing a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a power supply device showing a third embodiment of the present invention.

FIG. 5 is a circuit diagram of a main part of the same.

FIG. 6 is a graph showing a variation in output voltage of each power supply main body.

FIG. 7 is a circuit diagram of a conventional power supply device.

FIG. 8 is a graph showing a voltage drop of a backflow prevention diode with respect to an output current.

FIG. 9 is a graph showing a variation in output voltage of each power source main body.

[Explanation of symbols]

 1, 2 Power supply body 3 Load 4,5 Backflow prevention diode 6,7 Voltage detection circuit 8, 9 Voltage correction circuit 13 First error amplifier 25 Second error amplifier 27 Diode 31 Reference power supply + S, -S Remote sensing terminal + V, -V output terminal

Claims (4)

[Claims] 1. A direct current output voltage between output terminals is detected, and the detected voltage and a reference voltage are error-amplified by a first error amplifier, and the output voltage between the output terminals is increased based on an output from the first error amplifier. In a power supply device in which a plurality of power supply main bodies for controlling so as to keep the DC output voltage constant are connected in parallel, and a backflow prevention diode is inserted and connected between the output terminal of each of the power supply main bodies and a load, A voltage detection circuit that detects the voltage across the load is connected to the cathode of the prevention diode, and a variable command voltage whose value continuously changes according to the detection result from the voltage detection circuit is used as the first error amplifier. A power supply device comprising a voltage correction circuit for supplying to one of the input terminals. 2. A second error amplifier for error-amplifying a detection signal from the cathode of the backflow prevention diode and a reference voltage from a reference power source, and an anode connected to an output terminal of the second error amplifier. A diode for injecting the variable command voltage into one input terminal of the first error amplifier to raise the DC output voltage between the output terminals only when the detection signal from the cathode of the backflow prevention diode is lower than a predetermined value. The power supply device according to claim 1, wherein the voltage correction circuit is configured by 3. A voltage between the remote sensing terminals is detected, the detected voltage and the reference voltage are error-amplified by a first error amplifier, and the voltage between the remote sensing terminals is detected based on the output from the first error amplifier. In a power supply device in which a plurality of power supply main bodies for controlling so as to keep the voltage constant are connected in parallel, and a backflow prevention diode is inserted and connected between the output terminal of each of the power supply main bodies and the load, the remote sensing terminal is connected. A voltage detection circuit that is connected to the load side and that detects a voltage across the backflow prevention diode, and a variable command voltage whose value continuously changes according to the detection result from the voltage detection circuit And a voltage correction circuit which supplies the voltage to one input terminal of the error amplifier. 4. A second error amplifier that error-amplifies each detection signal from the anode and cathode of the backflow prevention diode, and an anode connected to the output terminal of the second error amplifier, Only when the detection signal from the anode is lower than a predetermined value, the voltage is corrected by a diode that injects the variable command voltage into one input terminal of the first error amplifier to raise the DC output voltage between the output terminals. The power supply device according to claim 3, wherein the power supply device comprises a circuit.