JPH11168832A - POWER SUPPLY DEVICE AND POWER SUPPLY SYSTEM USING THE SAME - Google Patents

Abstract

(57) [Problem] To compensate for a voltage drop of an output voltage caused by a voltage drop element such as an output diode or a transistor by using a circuit configuration having no short-circuit fault element of a power supply output, and to be independent of a load current. Provided are a power supply unit and a parallel power supply system capable of obtaining a stable output voltage. A device includes an element (diode, transistor, etc.) that approximates the characteristics of a diode with respect to a voltage drop of an output diode, and a means for generating a control voltage for correcting the voltage drop. The voltage obtained by the means is added to a reference voltage for setting an output voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC-DC converter, a DC-DC converter, and other power supply devices for supplying stable DC power to a load, and a power supply system in which the units are connected in parallel as a unit.

[0002]

2. Description of the Related Art Conventionally, a power supply such as an AC-DC or DC-DC converter is generally controlled by detecting an output voltage and feeding back to a main circuit of the power supply in order to keep an output voltage constant. Voltage feedback control is widely used. Here, the main circuit means a circuit having a function of converting AC or DC input power to predetermined DC power (regardless of accuracy). The accuracy does not matter, means that the power supply output is not stabilized or that the power supply is not sufficiently stabilized. Japanese Patent Application Laid-Open No. 58-198122 discloses a configuration of a power supply device connected in parallel using this voltage feedback control (FIG. 12). In the power supply A of FIG. 12, 26 is a switching circuit, 27 is a transformer,
8 is a rectifying and smoothing circuit, 29 is a driving circuit, 30 is a comparator, 3
1 is an error amplifier, 32 is an oscillator, and 33 is a triangular wave generator. A plurality of power supplies (A, B,...) Having the same configuration are connected in parallel to a common circuit by a diode 51 on the output side of the power supply as a wired-OR logic to supply power to the load. It is possible to supply up to a total current of the outputs of all the plurality of power supplies to the load.

The operation of the circuit shown in FIG. 12 will be described. When an unstabilized DC voltage is input, the DC voltage is converted to a desired DC power via an internal switching circuit 26, a transformer 27, and a rectifying / smoothing circuit 28. The output voltage applied to the load via the diode 51 is input to the non-inverting input terminal of the error amplifier 31. A reference voltage Vref for setting an output voltage is input to the inverting input terminal of the error amplifier 31.

An error amplifier 31 compares an error signal obtained by comparing and amplifying the output voltage and the reference voltage with a comparator 30.
To one input. The other input terminal of the comparator 30 receives the triangular wave pulse sent from the triangular wave generator 33 in synchronization with the output of the oscillator 32.

A pulse signal whose time width changes in accordance with the error signal output from the error amplifier 31 is output to the output terminal of the comparator 30. This pulse signal is supplied to the driving circuit 2
9, the output voltage of the power supply device is controlled so that the load voltage always becomes a constant value.

In the power supply device having this circuit configuration, even if some of the power supply units fail during the parallel operation and the output voltage drops due to the failure, if the power supply device whose output has dropped is within the redundancy range, Wired or connected diode 5
1, the power supply of the failed power supply is automatically cut off, so that power is continuously supplied to the load by the remaining power supply.

In an electronic system requiring high reliability of a power supply, for example, a magnetic disk storage device of a RAID system, in order to improve the reliability of the system, the power supply unit is provided with a parallel redundant operation function of a power supply unit and an automatic operation of a faulty power supply. It is required to have a disconnection function, a hot-swap maintenance function of the power supply device, and the like. Further, in terms of a circuit, it is necessary to reduce a short-circuit element of a power supply output and to eliminate a power supply failure potential that causes a power failure (system down) of the entire electronic system.

[0008] In the prior art, a terminal whose output is applied to a load is monitored. For this reason, when the forward voltage of the wired-or-connected diode changes with the change of the load current, the power supply device controls the output voltage to be fed back to the main circuit and to be always constant.
However, in the parallel power supply system having this circuit configuration, if any one of the power supply units connected in parallel short-circuits the voltage detection line for voltage feedback, all other power supply units connected in parallel short-circuit. And the whole parallel power supply system goes down. In other words, it was not a wired-or logic.

[0009]

Such a conventional parallel power supply system has a fatal problem from the viewpoint of high reliability.
It cannot be used for electronic systems that require high reliability. Therefore, the voltage detection line necessary for voltage feedback control is
The output diode is connected to the anode side (not the load side but the power supply side) (FIG. 1). As a result, when the voltage sense line of the power supply is short-circuited, in a power supply unit having a short-circuited terminal (hereinafter referred to as a faulty power supply unit), the overcurrent protection circuit operates and the output power is cut off. As a result, the output voltage from the other power supply unit is applied to the terminal of the failed power supply unit. However, the failed power supply unit is connected to the diode output terminal, which is a reverse current limiting element, and the terminal of the failed power supply unit is connected to the internal terminal. The internal resistance has been increased to allow for this. Therefore, by limiting the power inflow from the other power supply units, only the failed power supply unit is separated from the parallel power supply system.

However, in the circuit configuration of FIG. 1, since the target of voltage feedback control is the anode side of the output diode, when the load current increases, the output voltage of the power supply device decreases due to a change in the forward voltage drop of the output diode. . That is, in this configuration, the regulation characteristic of the output voltage is not good with respect to the fluctuation of the load current. Fluctuations in the output voltage of the power supply device are undesirable because they lower the operating margin of the load to which the voltage is supplied.

An object of the present invention is to eliminate a fault element due to a short-circuit of an output of a power supply device and to make it suitable for a highly reliable system shown in FIG.
An object of the present invention is to provide a power supply device having a circuit configuration described in (1), in which a voltage drop of an output voltage caused by a voltage drop element such as a diode in an output stage is corrected, and the regulation characteristics of the output voltage are improved. Another object of the present invention is to provide a power supply device in which the voltage drop correction control operates stably even in a parallel redundant operation of the power supply device (unit).

Other objects of the present invention will become apparent from the description of the present application and the description of the drawings.

[0013]

SUMMARY OF THE INVENTION An output diode, a transistor, and an FET generated by the flow of an output current of a power supply device.
A circuit having substantially the same or similar characteristics to the voltage drop characteristics of the voltage drop element such as a (field-effect transistor) is provided, and a signal (voltage) approximating the voltage drop characteristic of the voltage drop element is provided. This is achieved by correcting the reference voltage.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described. In the following embodiments, an AC-DC converter that converts an alternating current into a direct current will be described. However, these can be similarly realized by using a DC-DC converter that converts a direct current into a direct current having a different voltage. FIG. 2 shows a configuration of an AC-DC converter which forms a main circuit of a power supply device (power supply unit) according to the first embodiment of the present invention. In FIG. 2, 1 is an external AC power supply, 2 is an AC-DC converter having input terminals (two white circles shown on the left of the figure), 3
Is a current detection resistor, 4 is an operational amplifier, 5 is a ground terminal, 6
Is a voltage-current conversion circuit, 7 is a diode, 8 is a reference voltage source, 9 is an adder, 10 is an operational amplifier, 11 is a main circuit,
2 is a signal transmission means, 13 is a diode, 14 is a load,
5 is a DC output terminal.

The external AC power supply 1 is connected to a main circuit 11 inside the AC-DC converter 2. The high potential side output of the main circuit 11 is connected to the non-inverting input terminal of the operational amplifier 10 and the anode side of the diode 13. The low potential side output of the main circuit 11 is connected to the inverting input terminal of the operational amplifier 4 and one of the current detection resistors 3. The cathode side of diode 13 is connected to DC output terminal 15 of AC-DC converter 2. The other of the current detection resistors 3 is connected to the ground terminal 5. The load 14 is connected between the DC output terminal 15 and the ground terminal 5. The non-inverting input terminal of the operational amplifier 4
The output terminal of the operational amplifier 4 is connected to the ground terminal 5,
It is connected to the input of the voltage-current conversion circuit 6.

The output of the voltage-current conversion circuit 6 is connected to the anode of the diode 7 and to one input terminal of the adder 9. The positive terminal of the reference voltage source 8 is connected to another input of the adder 9, and the negative terminal of the reference voltage source 8 is connected to the ground terminal 5. The output of the adder 9 is connected to the inverting input terminal of the operational amplifier 10 and the operational amplifier 1
The output of 0 is connected to the main circuit 11 via the signal transmission means 12.

Here, the operation of this embodiment (FIG. 2) will be described. The AC voltage input from the external AC power supply 1 is AC
-The signal is input to the main circuit 11 inside the DC converter 2 and converted into a DC voltage by the main circuit 11. The DC current output from the main circuit 11 is supplied from the DC output terminal 15 to the load 14 via the diode 13, and flows through a closed loop returning to the main circuit 11 from the ground terminal 5 through the current detection resistor 3. At this time, the output terminal of the main circuit 11 and the DC output terminal 15
, A potential difference determined by the forward voltage drop of the diode 13 is generated. At the same time, the output current of the main circuit 11 flowing to the load 14 also flows to the current detection resistor 3, so that a potential difference determined at both ends of the current detection resistor 3 is determined by the product of the load current and the resistance value of the current detection resistor 3. . The operational amplifier 4 amplifies this potential difference and outputs a voltage proportional to the load current.

The voltage-current conversion circuit 6 and the diode 7
A circuit for generating a control voltage for correcting a voltage drop caused by the flow of the load current of the diode 13 is configured. The voltage-current conversion circuit 6 outputs a current proportional to the load current according to the output voltage of the operational amplifier 4 (voltage-current conversion), and supplies this to the diode 7. If economy permits, the diode 7 may be of the same type and standard as the diode 13. Normally, a small-signal element having a smaller current capacity than the diode 13 is used for the diode 7. When the output current of the voltage-current conversion circuit 6 flows,
It is important that the voltage drop characteristic of the diode 13 is substantially the same or similar.

The forward voltage generated by the diode 7 is output as a correction voltage for the voltage drop caused by the diode 13, and is added to the voltage command value of the reference voltage source 8 by the adder 9 at the next stage. Therefore, when the transistor 13 'or the like is used instead of the diode 13 (FIG. 3), it is necessary to use an element having substantially the same forward voltage drop characteristic as the transistor 13' or the like instead of the diode 7 (not shown). ).

The operational amplifier 10 (FIG. 2) constantly compares the output voltage of the main circuit 11 with the output voltage of the adder 9, and outputs the error voltage obtained by the comparison via the signal transmission means 12 to the main circuit. Return to 11. When the load current flows and the forward voltage of the diode 7 is input to the adder 9, the output voltage of the main circuit 11 increases by the forward voltage of the diode 7. Therefore, the diode 13 with respect to the load current
The output current value of the voltage-current conversion circuit 6 and the selection of the diode 7 are performed so that the forward voltage of the diode 7 and the forward voltage of the diode 7 with respect to the current output from the voltage-current conversion circuit 6 are substantially the same. Correction control is performed so that the voltage rise of the main circuit 11 cancels the voltage drop of the diode 7.
As a result, a constant voltage that does not depend on the load current is output to the DC output terminal 15, which is the output of the AC-DC converter 2.

According to the present embodiment, the output of the AC-DC converter (on the cathode side of the diode 13) does not have a voltage sense terminal for voltage feedback control, but has a stable and independent load current. Output voltage can be obtained.

In this embodiment, the correction of a voltage drop having a non-linear characteristic has been described on the assumption that the voltage drop element existing between the output of the main circuit 11 and the DC output terminal 15 is a diode. When the voltage drop element is not a diode but a resistor, a resistor is provided in place of the diode 7 in this configuration, and the linear voltage drop characteristic caused by the voltage drop element and the output voltage rise of the main circuit 11 are offset. As described above, if the constant of the resistor is determined, it is possible to correct the voltage drop of the linear characteristic. Even when the voltage drop element has a series characteristic of a diode and a resistor, if a diode and a resistor are provided in series instead of the diode 7, the voltage drop having a linear and non-linear composite Can also be corrected. Furthermore, if the parasitic resistance of the power supply line existing between the DC output terminal 15 and the load 14 is also included in the voltage drop element and taken into consideration, the voltage drop of the power supply line due to the parasitic resistance can be corrected. Thus, stable power supply to the terminal voltage of the load 14 can be realized. In order to secure higher reliability, a plurality of power supply units having the same configuration may be connected in parallel (FIG. 3). Here, 1 is an external input power supply, 11 is a main circuit, and 13 'to 1
3 ″ ′ is a transistor which is a voltage drop element, FET, 12
Is a signal transmission means, 10 is a comparison amplifier, 8 is a voltage source, 14
Is the load. A transistor or FET is used instead of the diode 13 in FIG. Although power supply units (units) using various voltage drop elements are shown connected in parallel, it is not necessary to mix them.

In FIG. 3, the output voltage may be monitored, and the base and gate of the transistor or FET may be turned on and off to cut off the current when the output of the power supply unit (unit) is short-circuited. Incidentally, 13 'indicates an example using a power transistor, 13 "indicates an example using a junction type FET, and 13"' indicates an example using a power MOS-FET. In any case, if an increase in the manufacturing cost of the power supply device is permitted, it is desirable to provide a control circuit 47 for controlling these. In addition, these voltage drop elements also need a function of restricting the reverse current.

Thus, even if the short-circuit element at the power output terminal is eliminated, and even if the voltage sense line is short-circuited, only the failed power supply unit is automatically disconnected from the power supply system by cut-off of the output diode and the like.
No system down occurs in the entire power supply device.

FIG. 4 shows an AC-D constituting a main circuit of a power supply unit (power supply unit) according to a second embodiment of the present invention.
2 shows a configuration of a C converter. 16, 17, and 19 are resistors,
18 is a diode. In addition, the same components as those shown in FIG. 2 are denoted by the same reference numerals. Main circuit 1
1 and the anode of the diode 13
Is connected. One of the resistors 16 is connected to the output of the operational amplifier 4, and the other of the resistors 16 is connected to the anode of the diode 18 and one input terminal of the adder 9. Other configurations are the same as those of the first embodiment shown in FIG.

Here, the operation of this embodiment will be described with reference to FIG. The points different from the first embodiment are 1).
As a voltage drop element, a series circuit composed of a resistor 19 and a diode 13 is used. 2) As a means for generating a control voltage for correcting a voltage drop caused by the resistor 19 and the diode 13, an output voltage of the operational amplifier 4 is used. Resistance 1
6, 17 and a diode 18, and a connection point between the resistor 16 and the diode 18 is used as an input to the adder 9. Other circuit operations are the same as those in FIG.

The operational amplifier 4 generates a voltage proportional to the load current. This voltage is input to a series circuit composed of the resistors 16 and 17 and the diode 18, and a circuit current flows through these series circuits, so that a voltage determined by the product of the circuit current and the resistor 17 and a diode with respect to the circuit current 18
Is a control voltage for correcting a voltage drop caused by the resistor 19 and the diode 13. This added voltage is supplied to a reference voltage source 8 by an adder 9 in the next stage.
Is added to the voltage command value. As a result, the output voltage of the main circuit 11 becomes equal to the voltage generated by the resistor 17 and the diode 1
8 is increased by the sum of the forward voltage 8 and the control in the direction to correct the voltage drop caused by the resistor 19 and the diode 13.

At this time, the linear component of the voltage drop is corrected by approximating the linear voltage drop generated by the resistor 19 with the voltage drop generated by the resistor 17. By approximating the non-linear voltage drop generated by the diode 13 by the forward voltage of the diode 18, the non-linear component of the voltage drop is corrected. This embodiment is different from the first embodiment in that a voltage-current conversion circuit is not required and a simple and low-cost circuit can be realized.

FIG. 5 shows the measurement results of the output voltage characteristics with respect to the load current in the circuit of FIG. The horizontal axis indicates the load current, and the vertical axis indicates the output voltage, 48 indicates the characteristics before the present invention is implemented, and 49 indicates the characteristics of the circuit to which the second embodiment of the present invention is applied. Note that, in the first embodiment shown in FIG. 2, characteristics similar to those of 49 can be obtained. As is apparent from FIG. 5, according to the present invention, the voltage drop correction control works effectively, the voltage drop with respect to the load current is greatly improved as compared with before the invention is implemented, and the load current extends over a wide range. The output voltage is constant.

FIG. 6 shows an AC-D constituting a main circuit of a power supply unit (power supply unit) according to a third embodiment of the present invention.
2 shows a configuration of a C converter. In FIG. 6, 20, 21
Is resistance. In addition, components having the same configuration as the components shown in FIG. 4 are denoted by the same reference numerals. One terminal of the resistor 20 is connected to the diode 18 and the resistor 17. One of the resistors 21 is connected to the resistor 16 and the anode of the diode 18. The other terminal of the resistor 20 is the resistor 2
1 and to one input of adder 9. Other configurations are the same as those of the second embodiment shown in FIG.

The second embodiment differs from the second embodiment in that a resistor 20 and a resistor 21 are provided to divide the forward voltage of the diode 18, and a connection point between the resistors 20 and 21 is added to the adder 9. Connect to input. The forward voltage of the diode 18 is a control voltage for correcting a non-linear voltage drop caused by the diode 13, as in FIG. By dividing the forward voltage of the diode 18 by the resistors 20 and 21, fine adjustment of the correction amount for the non-linear voltage drop of the diode 13 becomes possible.
Other circuit operations are the same as those of the second embodiment shown in FIG. This embodiment is, like the second embodiment, configured so that the cost can be reduced as compared with the first embodiment.

FIG. 7 shows the measurement results of the output voltage characteristics with respect to the load current in the third embodiment. The horizontal axis indicates the load current, and the vertical axis indicates the output voltage. 50 is the characteristic of the third embodiment. As a result of fine-tuning the non-linear voltage drop caused by the forward voltage error between the diode 18 and the diode 13 in FIG. 4, a more constant output voltage was obtained over a wide range of load current. The resistance 1
Depending on the fine adjustment including the constants of 6 and 17, when the output current is 60 A in FIG.
A gradient can be given to the load current so as to increase the output voltage up to that. As a result, the loss of the series resistance due to the wiring from the output terminal of the power supply device to the load can be compensated.

FIG. 8 shows an AC-DC power supply (power supply unit) constituting a main circuit when a voltage drop element is replaced with an element Q13 'different from a diode in the third embodiment of the present invention. 2 shows a configuration of a converter. Element Q
13 ′ includes a power transistor, a junction type FET,
There is a power MOS-FET. Whichever element is used as the element Q, it is desirable to provide a control circuit 47 for controlling these elements. The nonlinear drop voltage generated in the element Q is approximated by the forward voltage of the element Q'18 'having the same voltage drop characteristics as the element Q. Thereby, the nonlinear component of the voltage drop due to the element Q is corrected. As the element Q ′, an element having the same standard or model as the element Q may be used if an increase in the manufacturing cost of the power supply device is allowed. Usually, the element Q 'is a small signal element having a smaller power capacity than the element Q, and has substantially the same or similar voltage drop characteristics as the element Q when a circuit current flows.

FIG. 9 shows an AC-D constituting a main circuit of a power supply unit (power supply unit) according to a fourth embodiment of the present invention.
This shows a configuration in which a plurality of C converters are connected in parallel. 2
-1, 2-n are AC-DC converters, 9 is an adder, 2
2, 23 are operational amplifiers, 24 is a diode, and 25 is a signal line. In addition, the same components as those shown in FIG. 2 are denoted by the same reference numerals. In FIG. 9, AC-DC
The n converters 2-1 to 2-n have exactly the same circuit configuration, and are connected to the external AC power supply 1 and the load 14 in parallel. Hereinafter, an internal circuit of the AC-DC converter 2-1 will be described.

The output of the operational amplifier 4 is connected to the non-inverting input terminal of the operational amplifier 23 and the inverting input terminal of the operational amplifier 22, and the output of the operational amplifier 23 is connected to the anode of the diode 24. The inverting input terminal of the operational amplifier 23 is connected to the cathode of the diode 24, the non-inverting input terminal of the operational amplifier 22, the input of the voltage-current conversion circuit 6, and the same terminal of the other AC-DC converter and the signal line 25.
Connected by

One input of the adder 9 is connected to the output of the operational amplifier 22, the other input of the adder 9 is connected to the positive side of the reference voltage source 8, and the other input of the adder 9 is connected to the negative voltage.
The output of the current conversion circuit 6 and the anode of the diode 7 are connected. Other configurations are the same as those in FIG.

The operation of this embodiment will be described with reference to FIG. This embodiment is different from the first embodiment in 1).
N-parallel configuration such as the AC-DC converters 2-1 to 2-n; and 2) the output of the operational amplifier 4 is input to the maximum voltage detection circuit including the operational amplifier 23 and the diode 24; Input to the operational amplifier 22 and the output of the operational amplifier 22 to the adder 9; 3)
The voltage of the signal line 25, which is the output of the maximum voltage detection circuit, is input to the operational amplifier 22 and the voltage-current conversion circuit 6, and is also input to another AC-DC converter. Therefore, the differences will be mainly described. The other circuit operations are the same as those of the first embodiment shown in FIG.

The DC current output from the main circuit 11 is supplied to the load 14 from the DC output terminal 15 via the diode 13 and flows from the ground terminal 5 to the closed loop returning to the main circuit 11 through the current detecting resistor 3. . This operation is performed by other AC
The same applies to the -DC converter, and the load 14 can flow up to the total value of the output currents of the AC-DC converters 2-1 to 2-n.

The output current of each AC-DC converter is output to the output terminal of the operational amplifier 4 as a voltage proportional to the output current as described in the first embodiment. The operational amplifier 23 and the diode 24 constitute a so-called maximum voltage detection circuit, and the connection between the AC-DC converters via the signal line 25 causes the highest voltage among the output voltages of the operational amplifier 4 of each AC-DC converter. Is output to the signal line 25. That is, the signal line 25 indicates the maximum value of the output current of each AC-DC converter. In the operational amplifier 22, the voltage of the signal line 25 is applied to the non-inverting input terminal, and the output voltage of the operational amplifier 4 is applied to one inverting input terminal.

Therefore, in the operational amplifier 22, each AC-
The maximum value of the output current of the DC converter and its own AC
These error voltages are added to the voltage command value of the reference voltage source 8 by the adder 9, and the operational amplifier 10 and the signal transmission unit 1
2. Each AC-D is controlled by the voltage feedback control by the main circuit 11.
The output voltage of the main circuit 11 of the C converter changes according to the error voltage so that the output current follows the maximum value. As a result, the output current of each AC-DC converter is made uniform.

The above-described control for making the output current of each AC-DC converter follow the maximum current therein to equalize the output of each power supply unit is hereinafter referred to as maximum current follow-up control. The output voltage of each operational amplifier 4 has a value proportional to its own output current. In the maximum current follow-up control, by making this proportional coefficient equal between the AC-DC converters, each output current becomes uniform. Be transformed into

Conversely, if the proportional coefficient is set to a different value in each AC-DC converter, the output current distribution of each AC-DC converter can be changed. For example, in parallel operation of AC-DC converters having different current capacities, it is possible to arbitrarily set an optimal current distribution according to the current capacities of the respective AC-DC converters. Even in such a situation, maximum current follow-up control is possible.

Here, an AC-DC converter having a low current output is denoted by T, and an AC-DC converter having a current output twice as large is denoted by T2. The higher converter is not limited to an output current that is an integral multiple of the lower converter. Each of the voltages appearing at the output terminal of the operational amplifier 4 of T when T outputs the maximum current is equal to the voltage appearing at the output terminal of the operational amplifier 4 of T2 when T2 outputs the maximum current. The proportional coefficient of the output voltage of the operational amplifier 4 is set. In this parallel connection, if the maximum current tracking control is performed, that is, if the signal line 25 shown in the circuit configuration of FIG. 9 is provided, the tracking control based on the maximum output current of T2 can be performed. As a result, T
And a power supply system having T2 as an even number, it is possible to increase the lineup of rated output currents without increasing costs.

Further, simultaneously with the maximum current follow-up control, the voltage-
The circuit including the current conversion circuit 6 and the diode 7 generates a control voltage for correcting a voltage drop caused by the diode 13 as described in the first embodiment.
As a result, the output voltage of the main circuit 11 of each AC-DC converter is controlled so as to increase by the forward voltage of the diode 7. Instead of the diode 13, another transistor or FET as a voltage drop element may be used. 4th
In the embodiment (FIG. 9), unlike the first embodiment, the input of the voltage-current conversion circuit 6 is not the output voltage of the operational amplifier 4 but the voltage of the signal line 25. The voltage of the signal line 25 is the maximum value of the output voltages of the operational amplifier 4 of each power supply unit. AC with maximum current tracking control
When the output current of the DC converter is equalized, the voltage of the signal line 25 becomes equal to the output voltage of the operational amplifier 4, so that the operation of the correction control of the voltage drop caused by the diode 13 in the present embodiment is This is equivalent to the first embodiment.

The voltage rise of the output voltage of each main circuit 11 corresponding to the forward voltage of the diode 7 acts to cancel the voltage drop caused by the diode 13, and each AC-DC
The output voltage of the converter is kept constant with respect to the load current. In addition, the diode 13 according to the present embodiment
In the correction control of the voltage drop caused by the above, the voltage of the signal line 25, that is, the maximum value of the output current of each AC-DC converter is input. As a result, all ACs connected in parallel
Since the same correction control voltage is applied to the -DC converter, the above-mentioned output current distribution control based on the proportional coefficient of the operational amplifier 4 is not affected at all.

According to the present embodiment, the output current distribution control of each of the AC-DC converters connected in parallel enables parallel redundant operation of the power supply device, and at the same time, the output diode is not affected without affecting the control. , The output voltage during parallel redundant operation can be maintained at a constant value without depending on the load current.

In the fourth embodiment, each AC
The -DC converter has a circuit configuration in which the DC output terminal 15 serving as the output of the AC-DC converter does not have a voltage sense line for voltage feedback control. A highly efficient parallel power supply system can be constructed.

Further, the output of the main circuit 11 and the DC output terminal 1
5, the main circuit 11
Backflow of current to the AC-DC converter is prevented, and hot-swap maintenance can be performed during parallel operation of the AC-DC converters.

In the embodiment shown in FIG. 9, a diode is used as a voltage drop element existing between the main circuit 11 and the DC output terminal 15, and correction of a voltage drop having a non-linear characteristic is described. A linear voltage drop caused by a resistor or the like or a voltage drop including a linear component and a non-linear component caused by a diode and a resistor can be corrected in the same manner as in the first embodiment. FIG. 9 illustrates a circuit for correcting a voltage drop caused by a voltage drop element with reference to FIG. 2. In FIG. 9, the correction circuits of FIGS. 4 and 6 may be used. At this time, the effect of correcting the voltage drop is as described in FIGS.

FIG. 10 is a configuration diagram of a fifth embodiment of the present invention, in which a power supply is applied when a system such as a RAID type disk storage device requires high reliability.
The RAID type disk storage device has a configuration in which a plurality of disk storage devices are connected to a parallel redundant power supply system including a plurality of power supply devices, and a plurality of disk storage devices are used as one system. As shown in FIG. 10, in the RAID type disk storage device, data writing is performed as follows.
Control is performed so as to extend over each sequence, and data recovery is possible as long as the number of sequences is within the tolerance of the system when the system goes down in each sequence.

Therefore, in order to ensure the reliability of the storage device system, it is necessary to avoid the system down of each system, and the power supply device has a parallel redundancy function including hot-swap maintenance, and has an output function. Requires a circuit configuration that eliminates terminal short-circuit elements.

Also, with the recent trend toward lower voltages of semiconductor components, the allowable fluctuation range of the power supply voltage tends to be narrower. In order to ensure the reliability of the recorded and reproduced data, it is necessary to suppress fluctuations in the output voltage of the power supply device, which cause a reduction in the operation margin of the circuit. Further, in the RAID device, as shown in FIG. 10, a disk storage device is added, and the load current amount of the power supply device changes greatly. For this reason, in the power supply device, it is necessary to stabilize the output voltage against a change in the load current. In view of these circumstances, the power supply device of the present invention is indispensable for an electronic system that requires high reliability.

[0053]

According to the present invention, the voltage drop of the output voltage of the power supply caused by the output current of the main circuit flowing to the voltage drop element is generated from the signal proportional to the output current of the main circuit. The output voltage of the main circuit is corrected and controlled so as to increase the voltage value by the voltage drop of the voltage drop element by the correction voltage having characteristics similar to the voltage drop. Therefore, the output voltage of the power supply device has an effect of obtaining a constant voltage independent of the load current.

Further, if the parasitic resistance existing between the output of the power supply device and the load is included in the voltage drop element and compensated,
The output voltage can be corrected for the voltage drop of the power supply line.

According to the parallel redundant operation of the power supply units by the maximum current follow-up control, the voltage drop correction control is performed based on the maximum value of the output voltages of the power supply units.
The same correction control is given to all power supply devices. Therefore, the output current distribution for each power supply unit is not affected at all, and a stable output current distribution control and a constant output voltage independent of the load current can be obtained.

Since the circuit configuration does not have a voltage sense line for voltage feedback control on the load side of the voltage output terminal of the power supply device, elements that cause a short circuit fault in the output of the power supply device are reduced. In addition, since the voltage drop element is provided with a backflow limiting means such as a diode, the backflow of current to the power supply main circuit is limited or prevented. , A parallel redundant power supply system with high performance can be constructed.

The control circuit of the power supply device according to the present invention can be realized by semiconductor components, and has effects of not only a circuit using individual components but also miniaturization and cost reduction by an integrated circuit.

Although the present invention is a technique for keeping the output voltage of the power supply device constant, features that are significantly different from those of the prior art will be described as effects different from those described above. FIG. 11 shows a configuration diagram of a power supply circuit. 11, reference numeral 40 denotes a power supply device, 41 denotes an external input power supply, 42 denotes a converter main circuit,
3 is an output diode (voltage drop element Q), 44 is a load,
45 is an external input current source, 46 is a power supply output terminal, and 47 is a ground terminal. In FIG. 11, an external input power supply 41
Is connected to the converter main circuit 42 inside the power supply device 40. The high potential side output terminal of converter main circuit 42 is connected to power supply output terminal 46 via output diode 43. The low potential side output terminal of converter main circuit 42 is connected to ground terminal 47. The load 44 is connected to the power output terminal 4
6 and the ground terminal 47, the external input current source 4
5 is an anode of the output diode 43 and a ground terminal 47.
And the output diode 43 is connected in a direction in which a current flows.

Hereinafter, the features of the present invention will be described in comparison with the prior art. In FIG. 11, a voltage input from an external input power supply 41 is converted into a desired DC voltage by a converter main circuit 42 and applied to a load via an output diode 43. The voltage at the power supply output terminal 46, which is the output of the power supply device, has a voltage value that is lower than the output voltage of the converter main circuit 42 by the forward voltage of the output diode 43.

When the current of the external input current source 45 is zero,
In the prior art, the voltage feedback control of the voltage of the power supply output terminal 46 is performed, and in the present invention, the voltage of the power supply output terminal 46 is kept constant without depending on the load current in both technologies by the voltage drop correction control. This is as described above.

On the other hand, when a current flows from the anode of the output diode 43 by the external input current source 45 and the forward voltage of the output diode 43 increases, the prior art uses the voltage feedback control to control the voltage of the power supply output terminal 46. However, in the present invention, the voltage of the power supply output terminal 46 decreases as the forward voltage of the output diode 43 increases, so that the prior art and the present invention can be clearly distinguished. The above is one of the features of the present invention, which can be easily confirmed from outside the power supply device as described above.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply device (unit) necessary for a power supply system used in an electronic system requiring high reliability and a parallel connection thereof.

FIG. 2 is a circuit configuration diagram of a power supply device (unit) according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a power supply device (unit) in a case where a diode 13 in FIG. 2 is another voltage drop element.

FIG. 4 is a circuit configuration diagram of a power supply device (unit) according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a measurement result according to the second embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a power supply device (unit) showing a third embodiment of the present invention.

FIG. 7 is a diagram showing measurement results of the embodiment of FIG.

FIG. 8 shows a power supply unit (unit) in which the diode 13 is replaced with a voltage drop element Q or the like in the embodiment of FIG.
FIG. 3 is a circuit configuration diagram of FIG.

FIG. 9 is a circuit diagram showing a power supply device (unit) according to a fourth embodiment of the present invention and a parallel connection thereof.

FIG. 10 shows an electronic system R that requires high reliability.
FIG. 3 is a diagram illustrating a configuration example when the present invention is applied to an AID type disk storage device.

FIG. 11 is a diagram showing a circuit configuration for verifying characteristics of a power supply device (unit) according to the present invention.

FIG. 12 is a circuit configuration showing a conventional power supply unit (unit) and their parallel connection.

[Explanation of symbols]

1. External AC power supply, 2, 2-1 to 2-n AC-D
C converter, 3 ... current detection resistor, 4, 10, 2
2, 23 ... operational amplifier, 5, 47 ... ground terminal,
6, a voltage-current conversion circuit, 7, 13, 18, 24,
36, 43, 51 ... diode, 8 ... reference voltage source,
9 ... Adder, 11, 35 ... Main circuit, 12 ...
.., Signal transmitting means, 13 ′, a voltage drop element Q, 18 ′, which is different from the diode, and elements Q ′, 14, 39, 44, which have the same voltage drop characteristics as the element Q, load, 15.
... DC output terminals, 16, 17, 19, 20, 21 ...
... resistor, 25 ... signal line, 26 ... switching circuit, 27 ... transformer, 28 ... rectifying and smoothing circuit,
29 ... Drive circuit, 30 ... Comparator, 31 ... Error amplifier, 32 ... Oscillator, 33 ... Triangle wave generator, 34, 41 ... External input power supply, 36 '... Transistor, 36 "... Junction Type FET, 36 "'... MO
S-FET, 37 ... Comparison amplifier, 38 ... Voltage source, 40 ... Power supply device, 42 ... Converter main circuit, 45 ... External input current source, 46 ... Power supply output terminal, 47 ... Voltage drop element Control circuit.

Claims (5)

[Claims] An input terminal for inputting AC or DC power, a main circuit connected to the input terminal for converting input power to DC output, and connected between one end of an output of the main circuit and a DC output terminal. A voltage drop element having a function of guiding the output of the main circuit to a DC output terminal and limiting the reverse current, a reference voltage, and a voltage taken from one end of the output of the main circuit, and comparing the result. A first circuit that controls an output of the main circuit by feeding back to the main circuit, a second circuit that generates a signal proportional to an output current of the main circuit, and an output signal of the second circuit. And a third circuit for generating a voltage drop characteristic having substantially the same characteristic as the voltage drop characteristic of the voltage drop element and adding the voltage drop characteristic to a reference voltage of the first circuit. 2. The power supply device according to claim 1, wherein said third circuit generates a voltage drop characteristic having substantially the same characteristic as the voltage drop characteristic of said voltage drop element, and performs fine adjustment thereof. And a power supply device for adding to the reference voltage of the first circuit. 3. The power supply device according to claim 1, wherein the voltage drop element having the function of limiting the backflow is any one of a diode, a transistor, and an FET. 4. A power supply system in which two or more power supply devices of any one of the power supply devices according to claim 1, 2 and 3 are connected in parallel. 5. A power supply system in which two or more power supply devices are connected in parallel by arbitrarily combining the power supply devices according to claim 1, 2, and 3 with an allowance for duplication. A power supply system, wherein each of the one or more power supplies has a signal line interconnecting the two or more power supplies between an output signal of the second circuit and an input of the third circuit.