JPH1020947A - Redundant stabilized power source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize parallel driving be means of easily balancing current. SOLUTION: The device is used for parallel driving. Stabilized power source circuit 10A and 10B ate provided for current balancing circuits 30A and 30B to which currents for voltage drop are supplied based on output current flowing in one sense terminal of a load 12 and a power supply passage. In the input stage of the current balancing circuit 30A and 30B, output currents flowing in the self and opposite power source passages are added in resistors 34a and 34b. Then, parallel driving is executed by balancing the currents so that the output currents flowing in the stabilized power source circuit 10A and 10B (currents Ia and Ib flowing in the power source passages La' and Lb') become equal. Since the mutual currents are balanced while the current flowing in the opposite side is viewed, both circuits can be driven in parallel even if the currents are not completely balanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a redundant stabilized power supply circuit applicable to an AV server, a computer device, and the like. Specifically, by providing a current balance circuit in each of the stabilized power supply circuits and stabilizing the output voltage while monitoring each output current, a pair of stabilized power supply circuits can be operated in parallel regardless of load fluctuation. It was done.

[0002]

2. Description of the Related Art In an audio / video server (AV server), a computer device, or the like, even when the AC power supplied thereto is momentarily interrupted, the device driving voltage becomes a voltage higher than a specified value during the momentary interruption period. As described above, recently, a stabilized power supply circuit that performs parallel operation has been used.

FIG. 8 is a conventional example showing one example of such a conventional power supply.
ndant) It is called a stabilized power supply circuit.

In FIG. 8, a pair of stabilized power supply circuits 10
Diodes A and 10B are backflow prevention elements, respectively.
a, Db, and is connected to a load (such as an IC circuit) 12.

As a condition for the pair of power supply circuits 10A and 10B to operate in parallel, a difference between these power supply voltages (output voltages) must be normally kept at ± 50 mV, especially ± 30 mV or less. If a potential difference larger than this occurs, the power supply circuit with the lower voltage is cut off. This is because the diode Da or Db connected to the other power supply circuit is cut off by the higher output voltage, so that the cut-off power supply circuit side output voltage is not applied to the load 12.

Therefore, for example, the second stabilized power supply circuit 1
When 0B is cut off and the load 12 is driven only by the first stabilized power supply circuit 10A, the output current becomes Ib = 0, Ia = IL (IL is load current) as shown in FIG. 9A. When the potential difference between the output voltages Va and Vb reverses, Ia =
0, Ib = IL, and the cutoff relation of the power supply circuits 10A, 10B is reversed. Then, as shown in FIG. 9B, Ia
= Ib (= IL) and the load 12 is driven (parallel operation) by both the pair of power supply circuits 10A and 10B.

In the case of FIG. 8, it is necessary to stabilize the output voltage such that the difference between the two output voltages Va and Vb is at least within ± 50 mV in the parallel operation condition. On the other hand, as shown in FIG.
When a and Rb are connected, the period W until the current balance is achieved as shown in FIG. 11 can be made longer than in the case of FIG.

[0008]

In the above-mentioned redundant power supply device 10, the conditions for parallel operation are that the respective output voltages Va and Vb must be substantially equal as described above. However, both potential differences are ± 50m
In order to stabilize the respective output voltages so as to be equal to or lower than V, it is necessary to strictly select the element constants of the stabilized power supply circuits 10A and 10B. Further, even if the load fluctuates, it is necessary to operate in parallel without being affected by this. However, in the conventional example, particularly in the example of FIG. 10 in which a resistor is inserted, there is a problem that the parallel operation is easily affected by a load change.

In view of the above, the present invention has solved such a conventional problem. By adding a current balance function to each of the stabilized power supply circuits, a parallel operation is performed while mutually monitoring output currents. Another object of the present invention is to provide a redundant-type stabilized power supply that realizes stable parallel operation without strict selection of element constants and the like.

[0010]

In order to solve the above-mentioned problems, in a redundant stabilized power supply circuit according to the present invention, two stabilized power supply circuits are supplied to a load in parallel to drive the loads simultaneously. In the redundant type stabilized power supply for parallel operation, each stabilized power supply circuit is provided with a regulator and a current balance in which a voltage drop based on an output current flowing between one sense terminal of the load and the power supply path is supplied. And a voltage drop based on the output current flowing through the other stabilized power supply circuit is added to the input stage of the current balance circuit. It is characterized in that parallel operation is performed while maintaining current balance so as to be equal.

In the present invention, the output currents Ia and Ib flowing through the load 12 are detected using the line impedances of the power supply paths La 'and Lb'. This is because the voltage drop differs depending on the currents Ia and Ib. Therefore, the output current I
a and Ib can be monitored by the voltage drop.

The output currents Ia and Ib are added to resistors and applied to an operational amplifier of a current balance circuit to control one of the output voltages Va and Vb to balance the output currents Ia and Ib. Then, the output voltages Va and Vb also become constant, so that the pair of stabilized power supply circuits 10A and 10B can be operated in parallel at an output of 50%.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a redundant stabilized power supply circuit according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a connection diagram showing one embodiment of a redundant type stabilized power supply circuit according to the present invention.
1 and second stabilized power supply circuits 10A and 10B connected in parallel to DC power supplies 14a and 14b, respectively.
Having. As the DC power supplies 14a and 14b, those obtained by separately rectifying and smoothing AC power supplies are used. Since the pair of stabilized power supply circuits 10A and 10B have the same configuration,
Only one is illustrated and the other configuration is provided with a related reference,
The explanation is omitted.

Although a series regulator is exemplified as the stabilized power supply circuit 10A, a switching regulator may be used. In this example, a series regulator is used, and the series regulator 16A is connected to the power supply paths La and La 'constituting the stabilized power supply circuit 10A.

In this embodiment, a high-precision series regulator constituted by combining a series regulator and a shunt regulator is exemplified as the series regulator 16A. Therefore, the series transistor (control transistor) Qa is connected to the power supply path La, and the transistor Ta is controlled by the shunt regulator 20A.

As a symbol mark of the shunt regulator 20A, a symbol as shown in FIG. 3 is used. The shunt regulator 20A is, as shown in FIG.
A voltage comparator 22a has a built-in voltage reference source 24a connected to its inverting terminal, and a terminal 26 connected to its non-inverting terminal.
The reference voltage REFa is supplied from a.

The output of the voltage comparator 22a is
As a result, the collector current changes,
The anode-cathode current value (shunt current value) between the positive power supply terminal (cathode K) and the negative power supply terminal (anode A) is controlled by the reference voltage REFa. When the reference voltage REFa increases, the shunt current is controlled to increase accordingly.

Such a shunt regulator 20A
As shown in FIG. 1, the cathode K is connected in series with the resistor 21a such that the cathode K is on the positive power supply side, and further, the cathode K is connected to the base side of the series transistor Ta, so that the overall accuracy is high. A series regulator 16A can be configured.

The series transistor Ta is a diode D
The power supply terminal 17a is connected to the positive power supply terminal 17a through the power supply terminal a, and the power supply terminal 17a is connected to the load 12 via the positive power supply path La. The power supply path La 'on the negative side connected to the load 12 is connected to the DC power supply 1 via a power supply terminal 17b.
4a is connected to the negative side.

The sense (SENS) is further applied from both ends of the load 12.
E) The terminals 18a and 18b are led out, and the voltage across the load 12 is sensed. Therefore, the sense terminals 18a,
The voltage obtained between 18b is first divided by a voltage detecting means 19 comprising three resistors 19a to 19c connected in series to obtain a reference voltage REFa having a predetermined value, which is supplied to a reference terminal of a shunt regulator 20A.

When the drive voltage to the load 12 fluctuates, the fluctuation is sensed and the reference voltage REFa also fluctuates. In response, negative feedback is performed so that the voltage at the load terminal is constant, and the drive voltage is stabilized. It is planned.

In the present invention, a current balance circuit 30A is provided for such a configuration. Current balance circuit 3
0A has an operational amplifier 40A for a single power supply functioning as an error amplifier, and its output is supplied to the anode of the shunt regulator 20A via the resistors 31a and 31b.

The non-inverting terminal of the operational amplifier 40A is connected to the resistor 3
It is connected to the sense terminal 18b via 2a and to the power supply path La 'on the negative power supply terminal 17b side via a resistor 33a. Let the connection point be a.

The point a is connected to a current balance terminal 36a via a current adding resistor 34a, and the inverting terminal is connected to a current balance terminal 36a via a resistor 35a. The connection point between the resistors 34a and 35a is denoted by c.

The operational amplifier 40A constituting the above-described current balance circuit 30A can be one having the configuration shown in FIG. FIG. 11 shows a case where a plurality of PNP transistors are used, and a differential amplifier 41 including transistors Qa and Qb and a transistor Q
c and Qd, which are driven by the same current source 43 and have a transistor Q
A signal to be differentially amplified is given to a terminal 44 derived from c and Qd. A current mirror circuit 45 is connected on the current path of the first differential amplifier 41, and the output of one of the transistors Qe is guided to the output transistor Qf at the last stage connected to the current source 46, and is output from the terminal 47. Output signal V
out is obtained.

As shown in FIG. 5, the current balance circuit 40A is obtained as a linear output signal Vout for an input signal from -V to + V, but has a zero level for a signal below -V. Is clamped to. Therefore, if the voltage level of the input signal is -V or less, 0 volt is output.

As shown in FIG. 1, just like the stabilized power supply circuit 10A including the current balance circuit 30A, the second stabilized power supply circuit 10B is also configured and connected to the same load 12 in parallel. . Although the same reference numerals are given to the same portions as the first stabilized power supply circuit 10A and the description thereof is omitted,
Power supply terminals are denoted by 50a and 50b, and sense terminals are denoted by 51a.
When the current balance terminals are indicated by a and 51b and the current balance terminals are indicated by 36b, the positive power supply terminals 50a and 50b are connected to both ends of the load 12, and the sense terminals 51a and 51b are connected so as to sense the potential between both ends of the load 12.

Now, in the redundant type stabilized power supply device 10 configured as described above, the current balance terminal 36
a, 36b and the output voltage V
When a and Vb are not balanced and Va> Vb, the current Ia becomes the load current IL and Ib = 0 as shown in FIG. However, when the magnitude relationship between the output voltages Va and Vb is reversed, Ib = IL, Ia = 0, and
When the currents are balanced and Ia = Ib, a parallel operation state is set.

When the current balance terminals 36a and 36b are connected at the time when the current is not balanced, the current balance circuits 30A and 30B operate to perform balance control such that Ia = Ib. FIG. 7 shows this balance control.
This will be described with reference to FIG.

As shown in FIG. 7, Va> Vb until time t1.
Since the current balance terminals 36a and 36b are not connected, the currents Ia = IL and Ib = 0.

At the time t1, the current Ia is flowing through the line La ', so that its line impedance Ri (several m
Ω), and at the point a, that is, the current addition point c, the potential is −Vx like (−Ia · Ri). On the other hand, since Ib = 0, the point a ', that is, the point c' has the negative sense potential.

When the current balance terminals are connected to each other at time t1, the potential at point c 'becomes -Vx. As a result, the potential on the negative terminal side of the operational amplifier 40B drops, so that current amplification is performed, and the output current is converted into the voltage V2 by the resistors 31a and 31b, and the shunt regulator 20
B is applied to the anode.

The shunt regulator 20B has a built-in reference power supply 24a. Since the voltage of the reference power supply 24a is raised by the voltage V2, the shunt current flowing through the shunt regulator 20B is reduced. The current increases and the transistor Qb is turned on, and accordingly, the diode Db
, The output voltage Vb rises (see FIG. 7). When the output voltage Vb rises and the diode Db becomes conductive, the output current Ib flows.

When the output current Ib flows through the power supply line Lb ', a negative voltage drop (minus Vx') also occurs between the sense terminal c 'and the point a', which is the first stabilized power supply circuit 10B Minus voltage generated between the side points ac
Vx. As a result, the potential at the point c 'further decreases, the output voltage of the operational amplifier 40B further increases, and the output current Ib increases.

On the other hand, when the potential at the point a falls below -V on the operational amplifier 40A side, its output voltage is clamped to zero as shown in FIG.
A is not affected by the current balance circuit 30A at all. Therefore, the output voltage Va does not change (see FIG. 7). However, since the load current IL is IL = Ia + Ib, the output current I
The other output current Ia decreases as b increases (FIG. 7). Then, as shown in FIG. 7, at time t2 when Ia = Ib, the potentials at points a and a 'are balanced, and c = c' = a =
As a 'comes, the output currents Ia and Ib are balanced to enter the parallel operation state. When the current balance is lost, the same current control is performed again to maintain the equilibrium state.

When the relation of the output voltages is in the relation of Vb> Va, the current balance circuits 30A and 30B operate based on the second stabilized power supply circuit 10B, and the parallel operation state is maintained.

As described above, the current balance circuits 30A, 30
By using B, control is performed so that parallel operation can always be performed. As a result, parallel operation can be realized without taking a perfect current balance. When the current balance is realized, the line impedance can be used, so that the current detection resistor is not required.

Since the current balance circuits 30A and 30B are driven using the operational amplifiers 40A and 40B having a single power supply configuration, the output voltage of the higher output voltage (the larger output current) is fixed, and another output current is set. The transient response becomes quicker because it can be controlled to increase. Since the operational amplifiers 40A and 40B based on the negative voltage side are used, the configuration is simpler than when both the positive and negative voltages are used. Since the number of components of the current balance circuits 30A and 30B themselves is small, the circuit scale for performing parallel operation can be reduced.

[0040]

As described above, according to the present invention, there is provided a redundant operation type stabilized power supply for parallel operation in which two stabilized power supply circuits are supplied to a load in parallel to drive the load simultaneously. By providing a current balance circuit to which a voltage drop based on the output current flowing through the supply path is supplied, and controlling the current balance circuit with a voltage obtained by adding the voltage drop based on the output current flowing through the other stabilized power supply circuit, The output currents are controlled so as to be equal.

According to this, even when the current is not in a perfect current balance state, the current can be easily balanced, so that there is a feature that the parallel operation of the redundant-type stabilized power supply circuit can be realized with a relatively simple configuration. Therefore, the present invention is extremely suitable for application to a power supply device such as an AV server or a computer device as described above.

[Brief description of the drawings]

FIG. 1 is a system diagram of a main part showing an embodiment of a redundant type stabilized power supply device according to the present invention.

FIG. 2 is a configuration diagram of a shunt regulator.

FIG. 3 shows the symbol mark.

FIG. 4 is a connection diagram showing a specific example of a current balance circuit.

FIG. 5 is an explanatory diagram of the operation.

FIG. 6 is a diagram showing a relationship between output currents before current balance is achieved.

FIG. 7 is a diagram showing the relationship between output current and output voltage when current balance is achieved.

FIG. 8 is a system diagram showing a conventional example of a redundant type stabilized power supply device.

FIG. 9 is a diagram illustrating the operation of parallel operation.

FIG. 10 is a system diagram showing another conventional example of a redundant type stabilized power supply device.

FIG. 11 is a diagram illustrating the operation of parallel operation.

[Explanation of symbols]

10: stabilized power supply device, 10A, 10B: stabilized power supply circuit, 12: load, 16A, 16B: series regulator, 18a, 18b: sense end,
20A, 20B ... shunt regulator, 30A,
30B ... current balance circuit, 34a, 34b ...
Current adding circuit, 40A, 40B ... operational amplifier, L
a, La ', Lb, Lb' ... power supply path, Ta, T
b ... series transistor

Claims (3)

[Claims] 1. A redundant type stabilized power supply device for parallel operation, in which two stabilized power supply circuits are supplied to a load in parallel to drive the load at the same time, wherein each of the stabilized power supply circuits has a regulator and a load. A current balance circuit is provided for supplying a voltage drop based on an output current flowing between one of the sense terminals and the power supply path, and an input stage of the current balance circuit flows through the other stabilized power supply circuit. A redundant stabilization method characterized in that a voltage drop based on an output current is added, and a parallel operation is performed while maintaining a current balance so that output currents flowing through the two stabilized power supply circuits are equal. Power supply. 2. The regulator according to claim 1, wherein a series regulator or a switching regulator including a shunt regulator functioning as an error amplifier is used, and a series transistor is controlled by an output of the shunt regulator. 2. The redundant stabilized power supply device according to 1. 3. An error amplifier is provided in the current balance circuit, and a current addition terminal is provided at an input stage of the current balance circuit via a current addition resistor. The current balance circuit is configured so that the output current flowing through its own power supply path is added, and the output current of the one stabilized power supply circuit matches the output current of the other stabilized power supply circuit. 3. The redundant stabilized power supply device according to claim 1, wherein the power supply is operated.