JPH11136944A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device for positively stopping only a faulty power supply module, when the power supply device is operated in parallel with a plurality of power supply modules. SOLUTION: In a power supply device provided with a plurality of power supply modules A, B, and C that convert a DC voltage into a pulse a pulse voltage by switching operation, transforming the pulse voltage for rectifying and smoothing, and supplying an output voltage to a load, each of the power modules A, B, and C has a current balance circuit 4 that detects balanced and unbalanced states with the output current of other modules, a voltage protection circuit 6 with a comparator IC3 that compares an own output voltage with a preset reference voltage and sends a control signal for stopping own switching operation when the own output voltage exceeds the above reference voltage, and a voltage protection level switching circuit 10 that changes the reference voltage for detecting an abnormal voltage being inputted into a comparator IC1 of the voltage protection circuit 6, based on the result of the unbalanced state of the output current being detected by the current balance circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device,
More specifically, for example, the present invention relates to a power supply device including a plurality of power supply modules connected in parallel and applied to an electronic computer system such as a server computer.

[0002]

2. Description of the Related Art In general, this kind of power supply device usually has various protection functions for the purpose of improving reliability. As a typical example, there is an output overvoltage protection function, which monitors the output voltage of the power supply device and performs an operation of cutting off the voltage supply to the load when the output voltage exceeds a specified voltage.

A conventional example of a power supply device having a plurality of power supply modules connected in parallel and having such an output overvoltage protection function will be described with reference to FIG.

This power supply device includes three power supply modules A, B,
C is used to supply a necessary DC voltage. Since the circuit configurations of the three power modules A, B, and C are the same, the configuration of the power module A will be described below.

The power supply module A includes a transformer 1 for transforming a pulse voltage intermittently supplied from a DC power supply E by a switching operation of a power MOSFET 2, and rectifying and smoothing an AC output output to a secondary side of the transformer 1. And a rectifying / smoothing circuit 3 for supplying a rectified / smoothed DC voltage output from the rectifying / smoothing circuit 3 to the load 50 via a backflow prevention diode D1.

The switching operation of the power MOSFET 2 is controlled by a PWM control circuit 11, whereby the duty ratio of the primary side pulse voltage is controlled,
The average voltage value on the primary side is adjusted. Then, the pulse voltage is transformed by the transformer 1 and sent to the rectifying / smoothing circuit 3.

The power supply module A further includes a current balance circuit 4 for performing an operation of balancing output currents between the power supply modules A, B, and C, and a current control circuit for controlling the PWM control circuit 11 based on an output of the current balance circuit 4. An error amplifier circuit 5 for transmitting a signal and a voltage protection circuit 6 for transmitting a voltage control signal to the PWM control circuit 11 based on a DC voltage supplied from the rectifying and smoothing circuit 3 to the load 50 are provided.

The error amplifier circuit 5 includes an amplifier IC2 for amplifying the output of the current balance circuit 4, a resistor R10 connected to the output side of the amplifier IC2, and a diode D3 for backflow prevention.
A variable resistor VR5 and a resistor R6 connected between an output terminal V0 of the power supply and a ground terminal GND for applying a bias voltage to the output of the amplifier IC2; and an output terminal V0 of the power supply and a ground terminal. A photocoupler 7, a resistor R7, and a series circuit including a shunt regulator IC9 connected between the output terminal V0 and the ground terminal GND. An error between the DC voltage output between the DC voltage and the reference voltage set by the shunt regulator IC 9 is sent to the PWM control circuit 11 via the photocoupler 7 to control the operation of the PWM control circuit 11. ing.

The voltage protection circuit 6 includes a resistor R1, a resistor R2 connected between the output terminal V0 and the ground terminal GND, a resistor R3 to which a predetermined voltage VCC is supplied, and a Zener diode CR1 to generate a reference voltage Vz. Is connected to a plus terminal, a comparator IC1 supplied with a voltage divided by the resistors R1 and R2 to a minus terminal, a resistor R4 connected to an output side of the comparator IC1, and a photocoupler 8, The reference voltage Vz is compared with the divided voltage by the resistors R1 and R2 by a comparator IC1, and the DC voltage output between the output terminal V0 and the ground terminal GND becomes higher than a specified value. The divided voltage of R2 is the reference voltage V
z, the output of the comparator IC1 is set to a low level.
The switching operation of the power MOSFET 2 by the WM control circuit 11 is stopped.

In the same manner as the power supply module A, the other power supply modules B and C supply the rectified and smoothed DC voltage to the common load 50, and execute the same overvoltage protection operation as the power supply module A. It has become. Each of the power supply modules A, B, and C is configured to be detachable from the power supply device main body, and can be individually removed and replaced.

Although the above description is directed to the operation of the overvoltage protection, the same configuration can be applied to the case of detecting the shortage of the output voltage. The circuit element on the load 50 side can be protected.

[0012]

However, the above-described conventional power supply has the following problems.

That is, for the purpose of improving the reliability of the power supply device, the three power supply modules A,
In some cases, the power supply modules A, B, and C are connected in order to balance the supply current from each of the power supply modules A, B, and C to the load 50.
Are provided with a current balance circuit 4, respectively.

The power supply modules A, B, and C are voltage-controlled to supply the same output voltage to the load 50.

Therefore, for example, power supply modules A, B, C
Each of the power modules A,
B and C have the same output voltage. At this time, since each of the voltage protection circuits 6 involves a variation in abnormal voltage (overvoltage) detection, any one of the power modules A, B, and C It is unclear whether A, B, and C have performed the abnormal voltage detection operation. As a result, for example, an abnormal voltage detection operation in the power supply module B other than the actually failed power supply module A may precede an abnormal voltage detection operation in the power supply module A.

In such a case, the power supply module B which has detected the abnormal voltage first is turned off, but the power supply module A which has actually failed continues to operate even in this state. Is not canceled, and the next power supply module C is turned off.

In this way, even if three power supply modules A, B, and C are connected, a plurality of (or all) power supply modules B and C are stopped due to the failure of one power supply module A. The inconvenience of doing so occurs.

The present invention has been made in view of the above circumstances, and provides a power supply device capable of surely stopping only a failed power supply module when a plurality of power supply modules are operating in parallel. It is intended to do so.

[0019]

According to the first aspect of the present invention,
In a power supply device for supplying an output voltage to a load using a plurality of power supply modules connected in parallel, each of the power supply modules detects a balanced state with an output current of another power supply module, and a current balance circuit for detecting an unbalanced state. And, based on the detection result of the imbalance state of the output current by the voltage protection circuit that detects the abnormality of its own output voltage by comparing with a preset reference voltage and stops its own operation, and the current balance circuit, A voltage protection level switching circuit for changing a reference voltage for detecting an abnormal voltage in the voltage protection circuit.

According to the present invention, when one of the plurality of power supply modules connected in parallel fails and the power supply module becomes abnormal, the current balance circuit connects the power supply module to the power supply module. And an imbalance state of the output current with another power supply module is detected. The voltage protection level switching circuit changes the reference voltage for detecting the abnormal voltage of the voltage protection circuit in the failed power supply module based on the detection result of the imbalance state of the output current with another power supply module by the current balance circuit I do. This allows
When a plurality of power supply modules are operating in parallel, only the failed power supply module can be reliably stopped.

According to a second aspect of the present invention, there is provided a power supply apparatus comprising a plurality of power supply modules for converting a DC voltage into a pulse voltage by a switching operation, transforming the pulse voltage, rectifying and smoothing the pulse voltage, and supplying an output voltage to a load. Each of the power supply modules compares an output current of another power supply module with a current balance circuit for detecting an imbalance state, an imbalance state, and its own output voltage with a preset reference voltage. A voltage protection circuit including a comparator for sending a control signal for stopping its own switching operation when the voltage becomes equal to or higher than the reference voltage, and detecting the voltage based on a detection result of an imbalance state of an output current by the current balance circuit. And a voltage protection level switching circuit for changing a reference voltage for abnormal voltage detection input to a comparator of the protection circuit.

According to the present invention, when one of the plurality of power supply modules connected in parallel fails and the power supply module becomes abnormal, the current balance circuit connects the power supply module to the power supply module. And an imbalance state of the output current with another power supply module is detected. The voltage protection level switching circuit detects an abnormal voltage input to the comparator of the voltage protection circuit in the failed power supply module based on the detection result of the imbalance state of the output current with another power supply module by the current balance circuit. The reference voltage for The comparator of the voltage protection circuit compares its own output voltage with the changed reference voltage, and sends a control signal for stopping its own switching operation when its own output voltage becomes equal to or higher than the reference voltage. Thus, as in the case of the first aspect of the invention, when a plurality of power supply modules are operating in parallel, only the failed power supply module can be reliably stopped.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power supply according to an embodiment of the present invention will be described below with reference to FIGS.

The basic configuration of the power supply device of the present embodiment shown in FIG. 1 is the same as that of the conventional power supply device shown in FIG. 3, and the same circuit elements are denoted by the same reference numerals.

The power supply device of the present embodiment supplies a required DC voltage to a load 50 such as a server computer by using three power supply modules A, B, and C.

Since the three power supply modules A, B, and C have the same circuit configuration, the configuration of the power supply module A will be described in detail below.

The power supply module A transforms a pulse voltage supplied intermittently by the switching operation of the power MOSFET 2 from the DC power supply E, and rectifies and smoothes the AC output output to the secondary side of the transformer 1. And a rectifying / smoothing circuit 3 for supplying a rectified / smoothed DC voltage output from the rectifying / smoothing circuit 3 to the load 50 via a backflow prevention diode D1.

The switching operation of the power MOSFET 2 is controlled by a PWM control circuit 11, whereby the duty ratio of the primary side pulse voltage is controlled,
The average voltage value on the primary side is adjusted. Then, the pulse voltage is transformed by the transformer 1 and sent to the rectifying / smoothing circuit 3.

The power supply module A further includes a current balance circuit 4 for performing an operation of balancing output currents between the power supply modules A, B, and C, and a current control circuit that controls the PWM control circuit 11 based on an output of the current balance circuit 4. An error amplification circuit 5 for transmitting a signal; a voltage protection circuit 6 for transmitting a voltage control signal to the PWM control circuit 11 based on a DC voltage supplied from the rectifying and smoothing circuit 3 to the load 50; And a voltage protection level switching circuit 10 connected to the circuit 6.

An error amplifier circuit 5 operates based on the output of the current balance circuit 4 so that the output becomes low level when the output voltage to the load 50 is increased, and the amplifier IC2 operates so that the output becomes high level when the output voltage is decreased. Amplifier IC2
, An output terminal V0 and a ground terminal GN of the power supply.
D and a variable resistor VR5 and a resistor R6 for providing a bias voltage to the output of the amplifier IC2.
The power supply includes a photocoupler 7, a resistor R7, and a shunt regulator IC9 connected in series between an output terminal V0 and a ground terminal GND. The output of the current balance circuit 4 is amplified by an amplifier IC2. , An error between the DC voltage output between the output terminal V0 and the ground terminal GND and the reference voltage set by the shunt regulator IC9 is sent to the PWM control circuit 11 through the photocoupler 7, and the PWM control circuit Eleven operation controls are executed.

The voltage protection circuit 6 includes resistors R1 and R2 connected between the output terminal V0 and the ground terminal GND, a resistor R3 to which a predetermined voltage VCC is supplied, and a zener diode CR1 to generate a reference voltage Vz. Is connected to a plus terminal, a comparator IC1 supplied with a voltage divided by the resistors R1 and R2 to a minus terminal, a resistor R4 connected to an output side of the comparator IC1, and a photocoupler 8, The reference voltage Vz is compared with the divided voltage by the resistors R1 and R2 by a comparator IC1, and the DC voltage output between the output terminal V0 and the ground terminal GND becomes higher than a specified value. The divided voltage of R2 is the reference voltage V
z, the output of the comparator IC1 is set to a low level.
The switching operation of the power MOSFET 2 by the WM control circuit 11 is stopped.

The voltage protection level switching circuit 10 has a negative terminal connected to the output side of the amplifier IC2,
3 and a Zener diode CR1 for generating a reference voltage Vz.
And a resistor R9 connected between the output of the comparator IC3 and the plus terminal of the comparator IC1. The output level of the amplifier IC2 and the reference voltage Vz
Are compared with each other by a comparator IC3.
9 to the plus terminal of the comparison IC 1 and a reference voltage V by a voltage dividing operation by the resistors R8 and R9.
The voltage of the plus terminal of the comparator IC1 to which z is input is changed.

By making the circuit configuration of the voltage protection level switching circuit 10 in this manner, the voltage protection circuit 6 adds the reference voltage of the plus terminal of the comparator IC1 to the current balance circuit 4 in addition to the operation described above. The output voltage of the power supply module A is changed (reduced) in accordance with the output fluctuation of the power supply module A, so that an overvoltage detection operation can be performed even at a level lower than a preset value.

FIG. 2 shows an example of the configuration of the current balance circuit 4. As shown in FIG. The current balance circuit 4 converts the anode voltage of the backflow prevention diode D3 provided in the power supply module A and the anode voltage of the backflow prevention diode of each of the other power supply modules B and C into a resistor R11,
The signal is detected by a circuit composed of R12 and R13 and input to the positive terminal and the negative terminal of the comparator IC1.

The other power supply modules B and C shown in FIG.
In the same manner as in the power supply module A described above, each of the rectified and smoothed DC voltages is supplied to a common load 50,
An overvoltage protection operation similar to that of the power supply module A is executed. In addition, each power supply module A, B, C
Is configured to be detachable from the power supply body,
It can be removed and replaced individually.

Next, the operation of the above-described power supply device of the present embodiment will be described mainly on the operation of switching the overvoltage protection level of the voltage protection circuit 6 by the voltage protection level switching circuit 10.

It is assumed that a DC voltage is supplied to the common load 50 by any one of the three power supply modules A, B, and C.

In this state, the operation when the power supply module A fails (assuming here that the variable resistor VR5 is disconnected) will be described below.

In this state, the variable resistor VR5
As a result, the output voltage of the power supply module A rises, a higher voltage is supplied to the plus terminal of the amplifier IC2 through the current balance circuit 4 than before the failure, and the output of the amplifier IC2 becomes High level. The output of the comparator IC3 of the voltage protection level switching circuit 10 connected to the output side of the above becomes low level.

The output of the comparator IC3 is connected to the resistor R8.
, R9, the voltage at the plus terminal of the comparator IC1 to which the reference voltage Vz is input is reduced by the operation of the resistance voltage dividing circuit.

As a result, the reference voltage at the plus terminal of the comparator IC1 becomes lower than the initial reference voltage Vz. As a result, the output voltage of the power supply module A is lower than the preset DC voltage. The overvoltage of the power supply module A can be detected at the voltage level.

At this time, the output voltage of another power supply module B or power supply module C connected in parallel to the power supply module A tries to become the same output voltage as that of the power supply module A. The output of the amplifier IC2 of the module C becomes a low level. As a result, the output of the comparator IC3 becomes High level, and the voltage of the plus terminal of the comparator IC1 remains at the reference voltage Vz.
The overvoltage detection voltage is maintained at a higher level than the power supply module A described above.

With the above operation, the overvoltage detection voltage of the failed power supply module A is low, whereas the overvoltage detection voltage of the other power supply module B or C is high. During the ascending process, the power supply module A stops (turns off) due to overvoltage detection.

As a result, the failed power supply module A is disconnected from the load 50, and the protection voltage supplied from the power supply module B or the power supply module C to the load 50 becomes a normal voltage.

As described above, according to this power supply, in a power supply operating in parallel with a plurality of power supply modules A to C, only the failed power supply module A is reliably stopped, and the other power supply modules are stopped. The load 50 can be driven by the B or the power supply module C without any trouble. That is, by detecting the operation state of the current balance circuit 4 at the time of redundancy and switching the overvoltage detection level of the voltage protection circuit 6 according to the state, only the failed power supply module A is cut off.

In the above-described embodiment, the operation of the overvoltage protection has been described. However, the same configuration can be applied to the case of detecting the shortage of the output voltage. The power supply device and the circuit element on the load 50 side can be protected.

[0047]

According to the present invention, when a failure occurs in any one of a plurality of power supply modules connected in parallel and this power supply module becomes abnormal, only the failed power supply module is reliably detected. A power supply device that can be stopped can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a current balance circuit in the power supply device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing a conventional power supply device.

[Explanation of symbols]

 Reference Signs List A power module B power module C power module 1 transformer 2 power MOSFET 3 rectifying and smoothing circuit 4 current balance circuit 5 error amplifier circuit 6 voltage protection circuit 7 photocoupler 8 photocoupler 10 voltage protection level switching circuit 11 PWM control circuit 50 load

Claims (2)

[Claims] 1. A power supply device for supplying an output voltage to a load using a plurality of power supply modules connected in parallel, wherein each of the power supply modules determines whether the output current of another power supply module is balanced or unbalanced. A current balance circuit for detecting, a voltage protection circuit for detecting an abnormality of its own output voltage by comparing it with a preset reference voltage and stopping its operation, and detecting an imbalanced state of output current by the current balance circuit A voltage protection level switching circuit for changing a reference voltage for detecting an abnormal voltage in the voltage protection circuit based on a result. 2. A power supply device comprising: a plurality of power supply modules for converting a DC voltage into a pulse voltage by a switching operation, transforming the pulse voltage, rectifying and smoothing the pulse voltage, and supplying an output voltage to a load. A current balance circuit that detects a state of imbalance or imbalance with the output current of another power supply module, compares its own output voltage with a preset reference voltage, and its own output voltage is equal to or higher than the reference voltage. A voltage protection circuit including a comparator that sends a control signal for stopping its own switching operation when the current balance circuit detects an imbalanced state of the output current by the current balance circuit. And a voltage protection level switching circuit for changing a reference voltage for detecting an abnormal voltage to be input.