JP2930445B2 - Power supply unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention facilitates the adjustment of the output voltage of each power supply unit in a parallel operation and a parallel redundant operation of a plurality of power supply units. The present invention relates to a power supply unit capable of maintaining functions.

[0002]

2. Description of the Related Art Recently, in an electronic device such as an information processing device, the amount of data to be processed has been increased, and the required power amount has also been increased. As a result, the parallel operation of power supply units for large capacity and high reliability has been increased. doing. The parallel operation of the power supply units includes those with redundancy and those without. FIG. 5 shows a parallel operation without redundancy, and FIG. 6 shows a parallel operation with redundancy. In FIG. 5, the capacity is 5
0A power supply units PWR1 and PWR2 at 100A
Connected in parallel to the load LD1
Is controlled so as to bear each current.

On the other hand, in FIG. 6, power supply units PWR1 and PWR2 each having a capacity of 50A are connected in parallel to a load LD2 of 50A, and each power supply unit bears a current of 25A. With such redundant operation,
Even if one of the power supply units becomes inoperable due to a failure or the like, the other can supply the load current (50 A), thereby improving the reliability of the power supply system. Another redundant power supply unit 50A can be connected in parallel to the parallel system of FIG. 5 to provide a redundant operation system.

In any of the parallel operation systems, in order to further improve the reliability, it is important to adjust the output voltage of each power supply unit and balance the current (CB) for balancing the output current. Various circuit schemes have been devised.

FIG. 7 shows a basic configuration of a parallel operation system of a power supply unit widely used in the related art. The power supply units PWR11, PWR12, and PWR13 have the same internal configuration, and each have an input terminal IN, output terminals + OUT and -OUT, and a CB (current balance) terminal. Each input terminal IN is connected to an input voltage,
Each output terminal + OUT is commonly connected to one terminal of the load R, and each output terminal -OUT is commonly connected to the other terminal of the load R.

Power supply units PWR11, PWR12, P
The output currents of WR13 are Io1, Io2, Io, respectively.
3 is assumed. Power supply units PWR11, PWR12, PW
Each CB terminal of R13 is mutually connected by a common line LN. Each output current Io1, Io2, Io3
When the interval is balanced, no current flows through the line LN, and a state similar to the absence of the line LN is obtained. But,
As will be described later, when an unbalance occurs in the output current, a current flows in either direction in the line LN.
A current balance adjustment circuit in the power supply unit operates to keep the output current in balance.

FIG. 8 is a graph for explaining the current balance.
1 shows an example of a power supply unit. FIG. 9 is an equivalent circuit of the circuit of FIG. In FIG. 8, the DC input voltage is
Is applied to the primary side. The secondary side of the transformer T generates an output voltage between output terminals + OUT and -OUT via a rectifier circuit (diodes D21 and D22, a coil L, and a capacitor C1). Output voltages of the power supply units PWR11 and PWR12 are Vo1 and Vo
Let it be 2. The output voltage (Vo1, Vo2) is equal to the resistance R21
Are input to the (−) terminal of the operational amplifier 11 as output voltages (Vs1, Vs2) detected through the power amplifier. The reference voltage E is connected to the (+) terminal of the operational amplifier 11.

The operational amplifier 11 outputs to the PWM control circuit 12 a voltage proportional to the difference between the voltages at the (-) and (+) terminals. The PWM control circuit 12 performs PWM / FM control of the input current by controlling the transistor Tr based on the value of the output voltage from the operational amplifier 11. Thus, the output current is controlled. The output voltage is determined by the resistor R2
1, is also applied to the series circuit of R22 and R23. A connection point between the resistors R22 and R23 is connected to one end of a capacitor C2 described later. The other end of the capacitor C2 is a current balance terminal (CB1, CB2), a current transformer CT, a diode D23, a resistor R24, a capacitor C
2 detects a voltage proportional to the input current and generates it across capacitor C2. This voltage is applied to PWR11
And in PWR12, respectively, and V _i 1 and V _i 2.

By connecting the CB1 and CB2 terminals to each other, the relationship between the voltages in the circuit of FIG. 8 can be shown as in FIG. The voltage between both ends of each resistor R23 of the power supply units PWR11 and PWR12 is V
When _R 1 and V _R 2, V, _R 1 and V _R 2 varies according to the output voltage of each power supply unit. C
Via terminals B1 and CB2 and point P, V _i 1, V
_{i 2, V R 1, V} R 2 forms a loop, V _i 1 and V _i
2 and V _R 1 and V _R 2 are each opposite direction voltage.

The current balance operation of the circuits shown in FIGS. 8 and 9 will be described. First, the output voltage of the two power supply units PWR11 and PWR12 is Vo1 = Vo1.
When the current is balanced to 2 V _R 1 = V
Is _{R 2, V i 1 = V} i 2, the current Ii = 0 between the terminals CB1, CB2. Therefore, the two power supply units perform the same operation as when the terminals CB1 and CB2 are not connected. Next, when Vo1> Vo2, Io1> Io2
Therefore, V _i 1> V _i 2 and the current Ii flows from CB2 to CB1. In addition, the V _R 1> V _R 2.

As a result, the operational amplifier 11 and the PWM control circuit 12 of the power supply unit PWR11 output the output voltage Vo
1 and the operational amplifier 11 and the PWM control circuit 12 of the power supply unit PWR 12 output the output voltage V
It operates to increase o2. And Vo1 = Vo
2. When Io1 = Io2, the control operation stops. When Vo1 <Vo2, the operation is the reverse of the above. As described above, parallel operation in which the output current is balanced is realized.

FIGS. 10 and 11 show a block diagram and a detailed circuit diagram of an example of a conventional power supply unit. FIG.
11 and FIG. 11, the current detection circuit 1 has an output current I
A voltage Va proportional to out is output. Butt circuit 2 ', the resistor consists R _B, outputs a first end current detection circuit 1, is connected at the other end to CB terminal. Resistor R _B 1
The end is connected to the (-) terminal of the operational amplifier A3 of the comparison circuit 3 via the resistor R5. The other end of the resistor R _B (CB
The (terminal) is connected to the (+) terminal of the operational amplifier A3 via the resistor R6.

The comparison circuit 3 is operated by an operational amplifier A3.
The voltage Va and the voltage V _CB are compared, the difference is amplified, and the voltage Vc
Is output. Vc is a voltage that becomes a high level (“H”) when V _CB > Va. The voltage Vc is determined by the combining circuit 4
Is applied to the (+) terminal of the operational amplifier 11 through the diode D4. Reference voltage generating circuit 7 is a circuit for generating a voltage V _G as a reference for the output voltage, the power supply V _CC, a resistor R11, R12, R13, operational amplifier SR and the variable resistor V. Power Internal ADJ. The value of the output voltage V _G is the resistance V. Set by adjusting ADJ.

The output of the reference voltage generating circuit 7 is connected to the (+) terminal of the operational amplifier 11 through the resistor R9 of the synthesizing circuit 4. Synthesizing circuit 4, based on the output voltage V _G of the output voltage Vc and the reference voltage generating circuit 7 of the comparison circuit 3 generates a reference voltage V _ref, and supplies it to the (+) terminal of the operational amplifier 11. The reference voltage _Vref generated by the synthesis circuit 4 is
When the output voltage Vc of the comparator circuit 3 is 0V, the diode D4 is because it is off, becomes equal to the output voltage V _G of the reference voltage generating circuit 7. However, when Vc becomes “H”,
Diode D4 is turned on, V _ref is the value greater than V _G. The voltage obtained by dividing the output voltage detection circuit 10 by the resistors R1 and R2 is applied to the (-) terminal of the operational amplifier 11. The difference between this voltage and V _ref is amplified and PW
It is sent to the M / FM control circuit.

The operation of each power supply unit during the parallel operation of the power supply units shown in FIGS. 7, 10 and 11 will be described below. (1) Adjustment of output voltage The conventional output voltage adjustment method of the power supply unit performing the parallel operation is performed by monitoring the four points of the voltage Vo at the load end and the output currents Io1, Io2, and Io3 of each power supply unit. Unit output voltage adjustment resistor ADJ is adjusted and each reference voltage _Vref is set.

(2) Adjustment of output current balance When the output currents Io1, Io2, Io3 of the power supply units PWR11, PWR12, PWR13 are balanced,
Output voltage V _C of the comparator circuit 3 in each of the power supply unit becomes 0V. This is the same as that the CB terminal of each power supply unit is not connected to the CB terminals of other power supply units. Now, for example, if Io1 <Io2, Io3, then in power supply unit PWR11, V _CB > Va, and Vc
Becomes "H". When Vc becomes “H”, the operational amplifier 1
1 and the PWM control circuit 12 operate to increase the current Io1. Thus, the output current Io1,
A balance between Io2 and Io3 is obtained.

[0017]

The above-mentioned conventional parallel operation of power supply units has the following problems. As described above, the adjustment of the output voltage depends on the V.V. of the reference voltage generation circuit 7 of each power supply unit. It is necessary to adjust the ADJ resistance. In this case, the V.V. A
If the DJ is increased at a stretch, the output current will exceed the capability range of the current balance function, and the output current will drop more than one unit. Therefore, the V.V. The adjustment had to be made by repeating the ADJ resistance alternately and little by little. Therefore, the adjustment requires skill and a large number of measuring instruments, and takes a lot of time. Furthermore, as the number of power supply units arranged in parallel increases, the monitoring points, adjustment locations, and adjustment time during adjustment increase, making the operation extremely difficult. Therefore, a circuit system that can easily adjust the output voltage in a short time has been demanded.

The conventional current balance circuit has the following disadvantages. Power supply unit PWR11, PWR
12, if the PWR 13 is operating in parallel, for example, if the PWR 12 goes down, Io2 = 0, Va = 0 of the PWR 12
V. Therefore, PWR11 and PWR13 are Va
> V _CB , Vc became 0 V, and the current balance function was lost. Also, when an overvoltage condition occurs in one power supply unit, the output voltage of the other power supply units also increases due to the operation of the current balance circuit, and as a result, the power supply unit drops to a normal power supply unit. Was. In particular, when the above-mentioned phenomenon occurs during the parallel redundant operation, the addition of the current balance function causes the loss of the redundant function. The present invention eliminates the drawbacks of the above-described prior art, and can adjust the output voltage easily and in a short time. Even if the power supply unit goes down due to a failure or the like, the current balance function is not lost, and In redundant operation,
An object of the present invention is to provide a power supply unit that does not impair the redundancy function.

[0019]

A power supply unit according to the present invention is provided.
DOO, in power supply unit a plurality of power supply units for adjusting the output voltage based on the difference value between the reference voltage and the output voltage is connected in parallel with the load, each of said plurality of power supply units, adjustable Reference voltage generator that generates reference voltage
A raw circuit, and a circuit for transmitting the output voltage of the reference voltage generation circuit to itself and all other power supply units,
It is configured to include a circuit for receiving a reference voltage transmitted from another power supply unit, and a circuit for determining an output voltage based on the received reference voltage. Each of the power supply units includes an output current detection circuit for detecting a first voltage representing an output current value, and a terminal for detecting a second voltage representing an output current of another power supply unit performing parallel operation. Comparing the output current detection circuit and the ideal diode connecting the terminals with the first and second voltages. When the first voltage is smaller than the second voltage, the received reference voltage is compared with the first and second voltages. And a circuit for controlling the output current to be balanced so as to eliminate the difference between the two voltages. Further, each power supply unit is configured to include an upper limit circuit and a lower limit circuit for setting the upper and lower limits of the reference voltage, respectively.

[0020]

According to the above configuration, one of the plurality of power supply units is a master, and the other is a slave. The master receives a reference voltage from its own reference voltage generation circuit, and each slave receives a reference voltage from the master reference voltage generation circuit. To connect. By connecting in this manner, the reference voltages of all the power supply units can be simultaneously increased or decreased to the same level by adjusting one reference voltage generating circuit of the master, so that the output voltage can be easily adjusted. Become. Further, by comparing the output current of the power supply unit with the output current of another power supply unit using an ideal diode, even if one of the plurality of power supply units goes down, the remaining power supply units are affected. A normal current balance function can be exhibited without the need. Furthermore,
By the upper limit circuit and the lower limit circuit, the rise or fall of the reference voltage can be suppressed to a specified value or less.
Safe operation can be performed even when the reference voltage is abnormally increased or decreased due to the failure of the reference voltage generation circuit.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 show the configuration of an embodiment of the present invention. FIG. 1 is a diagram showing the parallel operation of three power supply units PWR1, PWR2, PWR3 having the same internal configuration, FIG. 2 is a block diagram showing the internal configuration of each power supply unit, and FIG. 3 is a detailed circuit of each power supply unit FIG. In FIG. 1, each power supply unit has output terminals + OUT and −OUT, a current balance terminal CB, a reference voltage output terminal VBO, and a reference voltage input terminal VBI. + O each
The UT terminal is connected to one end of the load R, and each -OUT terminal is connected to the other end of the load R. Each CB terminal is a common line LN
Connected by Three power supply units PWR1 to PWR3
One of them, for example, PWR1 is a master unit, and the other (PWR2, PWR3) are slave units. In the master unit (PWR1), the VBI and VBO terminals are directly connected. VB of each slave unit
Connect the I terminal to the VBO terminal of the master unit,
The O terminal is left open.

[0022] In Figures 2 and 3, the output current detection circuit 1 outputs the voltage Va proportional to the output current I _out.
The matching circuit 2 includes an operational amplifier A2 and a diode D3.
It is an ideal diode consisting of The output voltage Va of the output current detection circuit 1 is applied to the (+) terminal of the operational amplifier A2. A diode D3 is connected between the output terminal of the operational amplifier A2 and the CB terminal with the direction from the operational amplifier A2 to the CB terminal being the forward direction. The (-) terminal of the operational amplifier A2 is connected to the CB terminal. As the voltage V _CB generated at the CB terminal, the largest Va among the three units is output. The ideal diode configured as described above has Va
In the case of < _VCB , the power supply unit is completely turned off, and the power supply unit is not affected by an external voltage.

Both ends (voltages Va and V _CB ) of the ideal diode 2 are connected to the (-) and (+) terminals of the operational amplifier A3 of the comparison circuit 3 via the resistors R5 and R6, respectively. The operational amplifier A3 amplifies the difference between the voltages Va and V _CB and supplies the amplified difference to the (+) terminal of the operational amplifier A4 through the diode D4 of the synthesis circuit 4. The synthesizing circuit 4 includes a resistor R connected between the (+) terminal of the operational amplifier A4 and the ground.
9, the output voltage Vc of the comparison circuit 3 and VB
The reference voltage _Vref is generated by combining the input voltage of the I terminal with the input voltage.

The reference voltage generating circuit 7 includes a power supply V _CC , resistors R11, R12, R13, and an operational amplifier S with a built-in reference voltage.
R and the voltage adjustment variable resistor ADJ, the variable resistor V. Generating an adjustable reference voltage V _G by ADJ. The output V _G of the reference voltage generating circuit 7, the drive circuit 9
Is transmitted from the VBO terminal to the outside. As described above, in the master unit (PWR1), the VBO terminal and the VBI terminal are directly connected, and the slave unit (PW1) is connected.
The VBO terminal of R2, PWR3) is open. Accordingly, the output V _G of the reference voltage generating circuit 7 of PWR1 is, PW
It is input to R1 itself and the VBI terminals of PWR2 and PWR3.

In each power supply unit, the VBI terminal is connected to the (+) terminal of the operational amplifier A4 of the synthesizing circuit 4 via the receiving circuit 8 and the resistor R10. That is, the synthesizing circuit 4 of all the power supply units PWR1, PWR2, PWR3 is connected to the reference voltage generating circuit 7 of the master unit PWR1.
In the generated reference voltage V _G, to receive as a common reference voltage.

The output voltage _Vref of the synthesizing circuit 4 is input to the (+) terminal of the operational amplifier 11. The operational amplifier 11 is connected to the output voltage detected by the output voltage detection circuit 10 and V _ref.
And supplies the difference to the PWM / FM control circuit 12. The PWM / FM control circuit 12 controls the output voltage using this voltage. An upper limiter 5 and a lower limiter 6, which will be described in detail later, are connected to the output terminal of the synthesizing circuit 4 so as to clamp the upper and lower limits of the voltage _Vref .

The operation will be described below. (1) Adjustment respective power supply units of the output voltage has an adjustable reference voltage V _G, respectively. The single PWR1 in this as a master and supplies a reference voltage V _G of the master reference voltage input terminal V _B I of the power supply unit of the master itself and the other slave,
Thus, the output voltage of each power supply unit is controlled by a master reference voltage V _G. That is, the adjustment resistance V.V. of the master power supply unit PWR1. By adjusting the ADJ, the output voltages of a plurality of power supplies can be simultaneously increased or decreased to the same level. Therefore, the adjustment can be performed very easily and in a short time.

[0028] (2) the balance of the output current First, when the output current of the power supply unit PWR1~PWR3 are balanced, the output V _C of the comparator circuit 3 becomes 0V. Therefore, each power supply unit performs the same operation as when the CB terminal is not connected. Next, when the output current of one power supply unit is larger than that of the other power supply units, for example, when Io1, Io2 <Io3, Va of PWR3 is applied to the CB terminal of each power supply unit. You.
Therefore, in PWR1 and PWR2, VCB> Va, and as a result, Vc becomes “H” and _Vref increases. Therefore, PWR1 and PWR2 are controlled in the direction of increasing the output voltage. As a result, Io1 = Io2 = Io
The output voltage is controlled to be 3. Thus, parallel operation in which the output current is balanced is realized.

Next, if one power supply unit, for example, PWR2 goes down during operation, Io2 = 0 and Va = 0V of PWR2. However, Va of the larger value is applied to the CB terminals of PWR1 and PWR3, so that the current balance function works between the power supply units PWR1 and PWR3. (3) When the operation reference voltage generating circuit 7 of the upper limiter is defective V _G rises abnormally,
Each power supply unit performs control to raise the output voltage on the basis of the V _G. Further, when an overvoltage state occurs in one power supply unit, there is a possibility that the other power supply units will also be in an overvoltage state by the function of the current balance circuit in the above item (2). The upper limiter 5 is a circuit intended to stop the rise of the output voltage at a certain level. Assuming that the output voltage of the power supply is 5V and R1 = R2, _Vref = 2.5V
Becomes Here, assuming that the upper limit value of the output voltage is 5.2 V, E5 is set to 2.6 V, and this is supplied to the (+) terminal of the operational amplifier 11 through the ideal diode circuit (A5, D5). When V _ref is 2.6 V or less, the ideal diode circuit is turned off. When V _ref > 2.6V, the ideal diode circuit is turned on and V _ref is clamped at 2.6V. Therefore, the output voltage can be suppressed to 5.2 V or less.

[0030] (4) failure operating reference voltage generator circuit 7 of the lower limiter If the V _G drops abnormally, each power supply unit performs control to decrease the output voltage based on the V _G, stops the operation of the load There was a possibility. The lower limiter 6 is a circuit aiming to stop this decrease in output voltage at a certain level. Assuming that the lower limit value of the output voltage is 4.8 V, E6 is set to 2.4 V, and this is connected to the (+) terminal (V _ref ) of the operational amplifier 11 through the ideal diode circuits (A6, D6). When normal control is being performed, the ideal diode circuit is off. When V _ref <2.4V, the ideal diode circuit turns on and clamps V _ref to 2.4V. Therefore, it is possible to prevent the output voltage from lowering to 4.8 V or less.

As described above, according to the present embodiment, the output voltages of a plurality of power supply units can be adjusted easily and in a short time by adjusting one location. Further, even if the power supply unit stops due to a failure during the parallel operation, normal current balance control can be performed among the remaining power supply units. Furthermore,
The upper and lower limits of the reference voltage are suppressed by a preset value, and there is no abnormal increase or decrease.

FIG. 4 shows another embodiment of the present invention. FIG.
, The power supply units PWR1, PWR2, PW
The VBI terminal of R3 is connected to the power control device 15. Thus, the reference voltage V _G of the entire power supply unit can be dispensed from a device other than the power supply unit. Of course, in this case, the present invention is not limited to the power supply control device 15.

[0033]

According to the present invention, Te power unit odor <br/>, can be the adjustment of one location, to adjust the output voltages of all the power supply units. Therefore, adjustment of the output voltage can be performed easily and in a short time, which contributes to efficient operation of the power supply system. Also, during the parallel operation, even if the power supply unit fails, a normal current balance operation is performed among the remaining power supply units. Therefore, it contributes to the improvement of the reliability of the power supply system of the parallel operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram of each power supply unit of FIG. 1;

FIG. 3 is a circuit diagram of each power supply unit of FIG. 1;

FIG. 4 is a diagram showing another embodiment of the present invention.

FIG. 5 is a diagram showing parallel operation of the power supply units.

FIG. 6 is a diagram showing a parallel redundant operation of the power supply unit.

FIG. 7 is a diagram illustrating an example of a conventional technique.

FIG. 8 is a diagram for explaining current balance.

FIG. 9 is a diagram showing an equivalent circuit of the circuit of FIG. 8;

FIG. 10 is a block diagram of each power supply unit of FIG. 7;

FIG. 11 is a circuit diagram of each power supply unit of FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Output current detection circuit 2 Matching circuit (ideal diode) 2 'Matching resistance 3 Comparison circuit 4 Synthesis circuit 5 Upper limiter 6 Lower limiter 7 Reference voltage generation circuit 8 Receiving circuit 9 Drive circuit 10 Output voltage detection circuit 11 Operational amplifier 12 PWM control circuit 13, 14 operational amplifier 15 power supply control device A1 to A9 operational amplifier CB, CB1, CB2 current balance terminal C1, C2 capacitor CT transformer D1 to D6, D21 to D24 diode L coil LN connection line + OUT, -OUT output terminal Io1, Io2, Io3, I _R , I _out , I _i currents PWR1, PWR2, PWR3, PWR11, PWR1
2, PWR13 power supply unit R, LD1, LD2 load R0~R13, R24~R30, R _B resistor SR op T transformer VBI reference voltage input terminal VBO reference voltage output terminal V. ADJ adjusting variable resistor Vo1, Vo2, Vo3 output voltage V _i 1, V _i 2, the voltage V _R 1 of Va detected input voltage V _CB CB _{terminal, V R 2, V S 1} , V S 2, V S 3 , V _S 4, V
_CC voltage V _ref, V _G reference voltage

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02J 1/10 G05F 3/16 H02M 3/00

Claims (4)

(57) [Claims] 1. The method according to claim 1 , wherein the difference between the reference voltage and the output voltage is different.
Multiple power supply units for adjusting the output voltage
In the connected power supply, each of the plurality of power supply units has an adjustable reference voltage.
And a reference voltage generating circuit for generating the output voltage of the reference voltage generating circuit.
The circuit that transmits to one power supply unit and the circuit that receives the reference voltage transmitted from another power supply unit
And a circuit for determining an output voltage based on the received reference voltage.
A power supply unit comprising: 2. An output current detector for detecting a first voltage representing an output current value in each of the plurality of power supply units.
Displays the output current of the circuit and the other power supply units that are operating in parallel.
A second voltage detecting terminal, and an ideal die connecting the output current detecting circuit and the terminal.
It compares the diode, the first and second voltage, the first voltage and the second electrodeposition
If the received reference voltage is less than the first and second
2 so that there is no difference between the two voltages.
And a circuit that controls so as to balance the output current.
The power supply unit according to claim 1,
G. 3. The power supply unit according to claim 2 , wherein:
To suppress the rise of the reference voltage to a preset value
2. The electronic device according to claim 1, further comprising a limit circuit.
Source unit. 4. Each of the plurality of power supply units includes:
It is necessary to reduce the reference voltage to a preset value.
2. The electronic device according to claim 1, further comprising a limit circuit.
Source unit.