JPH1032921A - System for detecting undercurrent of power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of a power unit by making the power unit invalid when undercurrents are detected in all power supply sections, and valid when an undercurrent is detected in part of a plurality of power supply sections. SOLUTION: When the load current of a power unit becomes smaller than the minimum rated current of the unit, an undercurrent discriminating circuit 21 outputs AND of the undercurrent detecting signals (b) of all switching regulators and high-level undercurrent inhibit signals (e) to the alarm detecting circuits 112 of all switching regulators. The circuit 112 discriminates the undercurrent alarm signal (f) of each switching regulator of a delay circuit 113 as invalid and does not send a low-level alarm signal (c), and the switching regulators 11-11n continue operations. When the output current of only one of the regulators 11 becomes smaller, only the regulator 11 outputs an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a power supply device,
In particular, the present invention relates to an undercurrent detection method during parallel operation.

[0002]

2. Description of the Related Art As a conventional method for detecting an undercurrent of a power supply unit performing a parallel operation, for example, Japanese Unexamined Patent Publication No.
There is a power supply control method disclosed in Japanese Patent Application Laid-Open No. 7-107.

FIG. 3 is a block diagram showing this conventional technique. The power supply control system includes switching regulators 41 to 4n for converting an AC input voltage to a stabilized DC voltage,
The power supply control unit 5 controls the switching regulators 41 to 4n, and a control cable 6 connects the power supply control unit 5 to the power supply control unit 5. The switching regulator 41 includes a control circuit 411, an alarm detection circuit 412, and an AC-DC conversion circuit 413.

In this configuration, when the output current of the switching regulator 41 becomes equal to or less than the set value of the undercurrent detection, a signal b is sent from the control circuit 411 to the alarm detection circuit 412, and the alarm detection circuit 412
And outputs an alarm signal c due to insufficient current. The power control unit 5 checks whether the alarm signal c is output from the other switching regulators 42 to 4n.

As a result, when the alarm signal c is output only from the switching regulator 41, a signal a for turning off the power via the control cable 6 is sent from the power supply control unit 5 to the control circuit 411 in the switching regulator 41. Send out. Upon receiving the signal a, the control circuit 411 stops sending the on-pulse d, and the AC-DC conversion circuit 413
Of the switching transistor Q1 is stopped, and the operation of the switching regulator 41 is stopped. At this time, the other switching regulators 42 to 4n continue to operate.

When the power control unit 5 determines that the alarm signal c is output from two or more switching regulators, the power control unit 5 sends a power-off signal a to all the switching regulators 41 to 4n, The operation of the switching regulators 41 to 4n is stopped.

[0007] In addition to the above-mentioned conventional techniques, a method of attaching a dummy resistor for increasing the load current to the load side is generally used as a countermeasure against an undercurrent caused by a decrease in the load current.

[0008]

A first problem in the above-mentioned prior art is that when the load current becomes lower than the undercurrent value due to the operation state of the load such as a logic device to which power is supplied. Since an undercurrent alarm is output from all the switching regulators, the operation of the power supply stops even though the power supply is not faulty.

The second problem is that a dummy resistor must be mounted on the load side in order to increase the load current and continue the operation of the power supply as a countermeasure against insufficient current due to the decrease in load current. is there.

According to the present invention, in a power supply unit that performs parallel operation, when the load current becomes equal to or less than the shortage current value, the operation of the power supply unit is continued to improve the reliability of the power supply unit and increase the load current. To eliminate the need for a dummy resistor.

[0011]

An undercurrent detection method according to the present invention includes a plurality of power supply units, and a power supply control unit for controlling the plurality of power supply units, and a parallel operation of the plurality of power supply units. In the undercurrent detection method of the power supply device for supplying power to the load, undercurrent detection means for detecting undercurrent of each power supply unit and outputting an undercurrent detection signal, and ANDing the undercurrent detection signal Having an undercurrent determining means, when an undercurrent is detected in all of the power supply units, invalidates the undercurrent, causes the power supply from all of the power supply units to continue to be performed, When a part of the undercurrent is detected, this is made valid, only the power supply part where the undercurrent is detected is shut off, and the power supply from the other power supply parts is continuously performed. .

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.
And a power supply control unit 2 for controlling these components, and a control cable 3 for connecting the switching regulators 11 to 1n to the power supply control unit 2. The switching regulators 11 to 1n are connected in parallel, and a control circuit 111, an alarm detection circuit 112,
It includes a delay circuit 113 and an AC-DC conversion circuit 114. The power control unit 2 includes an undercurrent determination circuit 2.
1 is provided.

In such a configuration, the ON / OFF control of the switching regulators 11 to 1n is performed by transmitting the power control signal a from the power control unit 2 to the switching regulator 1
1 to 1n, and the ON-pulse d from the control circuit 111 turns ON / OFF the switching transistor Q1 of the AC-DC conversion circuit 114.
This is performed by turning it off.

FIG. 2 is a time chart showing a signal flow according to an embodiment of the present invention.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

First, when the load current decreases due to the operating state of the load such as a logic device, the output currents of all the switching regulators decrease, but the control circuits 111 of all the switching regulators reduce the currents below the minimum rated current. The case where the current value is detected will be described below.

When the control circuit 111 detects a current value smaller than the minimum rated current, the control circuit 111 outputs a high-level undercurrent detection signal b to the switching regulator 1.
1 to the shortage circuit 21 of the power supply control unit 2 via the control cable 3. An undercurrent detection signal b from another switching regulator is transmitted in the same manner. Undercurrent determination circuit 21 of power supply control unit 2
Calculates the logical product of the undercurrent detection signals b from all the switching regulators,
It is determined whether all of 1 to 1n have detected the undercurrent. As a result of the determination, if all the switching regulators have detected the undercurrent, the switching regulators 11 to 11 are transmitted from the undercurrent determination circuit 21 via the control cable 3.
The high-level undercurrent inhibit signal e is input to the 1n alarm detection circuit 112.

On the other hand, the delay circuit 113
The undercurrent detection signal b input to the low current alarm signal f after a predetermined time has elapsed due to the operation of the delay circuit 113.
Is input to the alarm detection circuit 112. The alarm detection circuit 112 uses the undercurrent inhibit signal e previously input from the undercurrent determination circuit 21 to
It is determined that the switching regulator individual undercurrent alarm signal f input from 13 is invalid. As a result, the alarm detection circuit 112 does not send the alarm signal c to the power supply control unit 2, and the switching regulators 11 to 1n continue to operate.

Next, the operation when only one switching regulator is used and the output current decreases due to some abnormality or failure will be described below.

In the switching regulator 11,
The control circuit 111 detects that the current value is smaller than the minimum rated current, and outputs a high-level undercurrent detection signal b to the delay circuit 113 in the switching regulator 11 and the undercurrent determination circuit 21 of the power supply control unit 2. Output. However, in other switching regulators, since the output current is equal to or greater than the minimum rated current, the control circuit 111
Becomes low level. The undercurrent detection signal b from each switching regulator is ANDed in the undercurrent determination circuit 21 of the power control unit 2. As a result, the undercurrent inhibit signal e
Becomes low level, and the low level undercurrent inhibit signal e is input to the alarm detection circuit 112 of each switching regulator.

Since the undercurrent inhibit signal e input to the alarm detection circuit 112 is at a low level, the switching regulator 11 does not invalidate the undercurrent alarm signal f output after a predetermined time has passed by the delay circuit 113, An alarm signal c is sent from the detection circuit 12 to the power control unit 2 via the control cable 3. Upon receiving the alarm signal c, the power control unit 2 controls the power supply O for stopping the operation of the switching regulator 11.
The FF signal a is sent to the control circuit 111. Control unit circuit 1
11 stops the output of the on-pulse d sent to the switching transistor Q1 of the AC-DC conversion circuit 114, and stops the operation of the switching regulator 11.

In other switching regulators, since the undercurrent alarm signal f from the delay circuit 113 of each switching regulator is not sent to the alarm detection circuit 12, the alarm signal c is not sent.
Continue the operation as it is.

As described above, one of the switching regulators 11
The operation in the case where the output current has decreased due to some abnormality or failure has been described for only one of the switching regulators. However, the above description also applies to the case where the output current has decreased in one to (n-1) switching regulators. Applicable. In this case, the operation of one to (n-1) switching regulators whose output current has decreased is stopped, and the other switching regulators continue to operate.

Next, the relationship between the operation of the embodiment of the present invention and the signals a to f will be described with reference to the time chart of FIG.

FIG. 2A shows the case where the load current becomes smaller than the minimum rated current due to the operation of the load such as a logic device when the power control signal a is in the ON state, that is, in the power ON state. The undercurrent detection signal b detected by the control circuit 111 of the regulators 11 to 1n becomes high level. This high level undercurrent detection signal b
Is a delay circuit 113 of each switching regulator,
It is output to the undercurrent judging circuit 21 of the power control unit 2.

The undercurrent determination circuit 21 calculates the logical product of the undercurrent detection signals b from all the switching regulators. As a result, the undercurrent determination circuit 21 outputs the high-level undercurrent inhibit signal e to the alarm detection circuits 12 of all the switching regulators. The alarm detection circuit 12 determines that the switching regulator individual undercurrent alarm signal f sent after a predetermined time from the delay circuit 113 is invalid, and does not send out the low-level alarm signal c. 1n continues the normal ON operation.

FIG. 2B shows a case where only one switching regulator 11 is used and the output current is reduced due to some abnormality or failure. The undercurrent detection signal b sent from the control circuit 111 of the switching regulator 11 is shown in FIG. The level becomes high level.

On the other hand, another switching regulator 12
.About.1n operate normally, and the undercurrent detection signal b sent from the control circuit 111 becomes low level. Undercurrent detection signal b of switching regulators 11-1n
Takes a logical product in the undercurrent judging circuit 21 of the power supply control unit 2. As a result, the undercurrent determination circuit 21 outputs the low-level undercurrent inhibit signal e to the alarm detection circuit 112 of each switching regulator. Thereby, in the switching regulator 11,
The alarm detection circuit 112 does not invalidate the undercurrent alarm signal f delayed for a predetermined time by the delay circuit 113, and sends a low-level alarm signal c to the power supply control unit 2.

Upon receiving this signal, the power control unit 2 sends a power control signal a for stopping the operation of the switching regulator 11 to the control circuit 111. The control circuit 111
The transmission of the on-pulse d is stopped, and the operation of the switching regulator 11 is stopped. In other switching regulators, since the undercurrent alarm b from the control circuit 111 of each switching regulator is at a low level, the normal ON operation is continuously performed.

In the embodiment of the present invention, a switching regulator including an AC-DC conversion circuit as a power supply unit has been described. However, a switching regulator including a DC-DC conversion circuit may be used. It is clear that the present invention can be applied to a power supply device using the power supply unit of (1).

[0032]

As described above, the first embodiment according to the present invention is described.
The effect of (1) is that in a power supply device that performs switching regulator parallel operation, it is possible to prevent the operation of the power supply device from being stopped when the load current decreases due to the operation state of a logic device or the like to which power is supplied. That is, the reliability of the power supply device can be improved.

The second effect is that the dummy resistor used when the load current is small becomes unnecessary.

[Brief description of the drawings]

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

FIG. 2 is a time chart showing a signal flow according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional technique.

[Explanation of symbols]

 11 to 1n Switching regulator 111 Control circuit 112 Alarm detection circuit 113 Delay circuit 114 AC-DC conversion circuit 2 Power supply control unit 21 Undercurrent determination circuit 3 Control cable

Claims (7)

[Claims] An undercurrent is detected in each of a plurality of power supply units for supplying power to a load by parallel operation, an undercurrent detection signal is output, and a logical product of the plurality of undercurrent detection signals is obtained. A power supply unit that detects an undercurrent, invalidates the detected power, and continuously supplies power from all power supply units. 2. An undercurrent detection signal is output from each of a plurality of power supply units that supply power to a load by parallel operation, and an undercurrent detection signal is output. If an undercurrent is detected in a part of the power supply unit, this is enabled, only the power supply unit where the undercurrent is detected is shut off, and the power supply from the other power supply unit is continued. An undercurrent detection method for a power supply device. 3. A plurality of power supply units for supplying power to a load in a parallel operation, each of the plurality of power supply units detecting an undercurrent, outputting an undercurrent detection signal, and calculating a logical product of the plurality of undercurrent detection signals. If an undercurrent is detected in one of the power supply units, this is invalidated, the power supply from all power supply units is continued, and if an undercurrent is detected in some of the power supply units. A method for detecting an undercurrent in a power supply device, wherein only a power supply unit in which an undercurrent is detected is shut off, and power is continuously supplied from another power supply unit. 4. An undercurrent detection of a power supply device including a plurality of power supply units and a power supply control unit for controlling the plurality of power supply units, and supplying power to a load by operating the plurality of power supply units in parallel. In the method, there is an undercurrent detection unit that detects an undercurrent of each power supply unit and outputs an undercurrent detection signal, and an undercurrent determination unit that calculates a logical product of a plurality of the undercurrent detection signals. An undercurrent detection method for a power supply device, wherein when an undercurrent is detected by a power supply unit, the power supply unit invalidates the undercurrent and continues power supply from all power supply units. 5. An undercurrent detection of a power supply device that includes a plurality of power supply units and a power supply control unit that controls the plurality of power supply units, and supplies power to a load by operating the plurality of power supply units in parallel. In the method, there is an undercurrent detection unit that detects an undercurrent of each power supply unit and outputs an undercurrent detection signal, and an undercurrent determination unit that obtains a logical product of the plurality of undercurrent detection signals. If an undercurrent is detected in a part of the power supply unit, this must be enabled, only the power supply unit in which the undercurrent is detected is shut off, and power is continuously supplied from other power supply units. An undercurrent detection method for a power supply device. 6. An undercurrent detection of a power supply device including a plurality of power supply units and a power supply control unit for controlling the plurality of power supply units, and supplying power to a load by parallel operation of the plurality of power supply units. In the method, there is an undercurrent detection unit that detects an undercurrent of each power supply unit and outputs an undercurrent detection signal, and an undercurrent determination unit that calculates a logical product of a plurality of the undercurrent detection signals. If the power supply unit detects an undercurrent, it invalidates this.If the power supply unit continues to supply power from all the power supply units, and if some of the power supply units detect the undercurrent, An undercurrent detection method for a power supply device, wherein this is made effective, and only a power supply unit in which an undercurrent is detected is shut off, and power is continuously supplied from another power supply unit. 7. An undercurrent detection of a power supply device including a plurality of power supply units and a power supply control unit for controlling the plurality of power supply units, and supplying power to a load by parallel operation of the plurality of power supply units. In the method, an undercurrent is detected, an undercurrent detection signal is output to the delay circuit of the power supply unit and the power control unit, and the operation of the power supply unit is stopped by a power-off signal from the power control unit. A control circuit of the power supply unit; a delay circuit of the power supply unit that delays the undercurrent detection signal for a predetermined time and outputs the undercurrent alarm signal to an alarm detection circuit of the power supply unit; The logical product of the undercurrent detection signals from the respective power supply units is taken, an undercurrent determination signal is output to the alarm detection circuit of the power supply unit, and output from the alarm detection circuit of the power supply unit. Allah The power supply control section for outputting a power supply off signal to a control circuit of the power supply section in response to the alarm signal; and the alarm signal to the power supply control section based on the undercurrent alarm signal and the undercurrent determination signal. An undercurrent detection method for a power supply device, comprising: an alarm detection circuit of the power supply unit for determining whether to output.