JPH0568325A - Circuit protector - Google Patents

Abstract

PURPOSE:To provide a circuit protector which enables highly reliable detection of an overcurrent without a fear of its malfunctioning to abnormality occurring on the side of load, in the power system of an electronic computer. CONSTITUTION:Voltage digital data proportionate to the current supplied to the circuit on load side are preserved in a resistor 308 through an A/D converter 307 from a resistor 302, and the materialization of the condition of the current break is judged by a break condition judging circuit 304, on the bases of the overcurrent judgment results in each of an alarm judging circuit 305 and a limit judging circuit 306 and the error condition lead out results accompanying the operation error of the circuit on load side from each of the first load error lead-out line 321 and the second load error lead-out line 322. And the off signal of a power transistor 301 is given from power system controller 50 to a transistor control circus 303 to break the current supply from the power line 311 on the power source side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention cuts off the supply of an electric current to an electronic circuit formed on a printed board of an electronic device when the electric current is excessively large, thereby causing a fatal damage to the electronic circuit. The present invention relates to a circuit protection device that prevents

[0002]

2. Description of the Related Art For example, an electronic circuit is formed on a printed circuit board which constitutes a large number of modules inside an electronic computer. The electronic circuit is formed between a power supply section and a load side electronic circuit in this electronic computer. Monitor the fluctuation of the flowing current value,
There is provided a circuit protection device that prevents the electronic circuit from being fatally damaged or causing a fire by cutting off the supply of an excessive current.

That is, due to an abnormality in a component forming an electronic circuit on the load side with respect to the power source, an excessive current may flow into the circuit to generate heat, leading to smoking or ignition. In order to prevent this, conventionally, the following circuit protection means has been used.

The first circuit protection means is provided with an overcurrent detection circuit on the power supply side, and when the overcurrent detection circuit detects that a current exceeding a certain value is flowing, the power supply itself outputs its output. Cut off. The second circuit protection means is provided with a breaker for the output of the power supply, and cuts off the current supply to the load side by detecting an overcurrent at the breaker. The third circuit protection means is
A breaker is provided at the load side input section, and the current supply is cut off by detecting overcurrent at this breaker.

In general, in electronic equipment, especially in a typical electronic computer, even if they are of the same model, the number of modules and printed boards differ depending on the system scale, and the user initially has a small system configuration. It is often introduced and the scale is expanded in accordance with the expansion of business. For this reason,
It is desirable that the power supply of the electronic computer can withstand future system expansion, and normally the power supply capacity (rated current) is based on the load current with the maximum number of modules.
Is set.

Here, in the above-mentioned first circuit protection means, that is, the circuit for protecting the circuit by detecting the overcurrent flowing to the load side by detecting the overcurrent of the current, the current flowing when the load side becomes abnormal becomes the power source. It is necessary to exceed the overcurrent detection value, and this overcurrent detection point is usually 1
It is often set to about 10 to 120%.

However, as described above, for a power supply having a large capacity assuming the maximum system scale,
In the case of an electronic computer with a small-scale system configuration connected to the load side, even if an abnormality occurs in the load side circuit and a current that greatly exceeds the steady current of the load flows, the overcurrent detection value of the power supply is In some cases, the current may not be exceeded, and current supply may not be cut off, resulting in circuit damage.

Therefore, a power supply for the electronic computer is provided independently for each very small circuit block, and an overcurrent detection point that slightly exceeds the rated current for each block is set for each power supply. It may be possible to install an overcurrent detection circuit, but the system configuration becomes complicated and addition is complicated, and the risk of power shutdown due to malfunction increases in proportion to the number of installations, and reliability is impaired. There is.

It is possible to change and set the overcurrent detection point of the power supply side overcurrent detection circuit according to the actual load current corresponding to the actual system scale. It is necessary to change the overcurrent detection point, and even if the power supply unit of the same type cannot be used for other computer systems as it is, compatibility cannot be maintained. It is necessary to reset the current detection point, which is very troublesome to handle and is prone to human error.

On the other hand, the second and third circuit protection means, that is, the circuit protection means provided with a breaker on the power source side or the load side, is essentially the same as the above-mentioned means for protecting by the overcurrent detection of the power source. However, if you try to make the overcurrent detection point of the breaker correspond to the steady current on the load side, it is necessary to install a breaker independently for each small block in the system, which complicates the system configuration. In addition, there is a problem that reliability is deteriorated due to an increased risk of malfunction.

[0011]

That is, from the viewpoint of protecting an electronic circuit, a circuit that detects an overcurrent and cuts off the current supply is installed everywhere in the system, that is, in each small block. Although fine-grained protection is possible, increasing the number of installations increases the risk of malfunctions, that is, the risk of interrupting the supply current regardless of whether or not the circuit is operating. To achieve this, the reliability of overcurrent detection in the overcurrent detection / cutoff circuit itself must be ensured.

The present invention has been made in view of the above problems,
To provide a circuit protection device that enables reliable overcurrent detection without fear of malfunction due to an abnormality that occurs on the load side even when a large power supply is provided in consideration of system configuration expansion. To aim.

[0013]

That is, a circuit protection device according to the present invention is provided between a power source and an electronic circuit on the load side, and turns on / off a power signal according to a command from a power system controller.
The circuit includes a closing / closing circuit for breaking the current, and current detecting means for detecting the current value of the power supply signal supplied to the load side circuit, and the load side supply current value detected by the current detecting means are steady. A first overcurrent determining means for determining that a first overcurrent value higher than the current value is exceeded, and a second overcurrent in which the load-side supply current value detected by the current detecting means is higher than the first overcurrent value Second to judge that the value has been exceeded
Overcurrent determining means, first error deriving means for deriving an error signal associated with the operation error of the load side circuit, and second error deriving means for deriving a save end signal of error information associated with the operation error of the load side circuit. And the load side circuit based on the respective overcurrent determination results by the first overcurrent determination means and the second overcurrent determination means and the error state derivation results by the first error derivation means and the second error derivation means. And a cutoff condition determining means for determining a current cutoff condition for the power supply system control unit and issuing a power supply signal cutoff command from the power supply system control unit.

[0014]

That is, there are four conditions of two systems, that is, the respective overcurrent determination results by the first and second overcurrent determination means and the respective error state derivation results by the first and second error derivation means. In the determination element, for example, when the first overcurrent determination means determines that the first overcurrent value is exceeded, the first and second error derivation means further cause an error signal of the load side circuit and an error information saving end signal, respectively. Is derived, or in a state where the first and second overcurrent determining means have determined that the first and second overcurrent values are exceeded, the error signal of the load side circuit is further provided by the first error deriving means. If any of the current cutoff conditions is satisfied, the power supply signal to the load side circuit will not be cut off, so reliable and reliable overcurrent detection / cutoff can be performed. Circuit protection is so performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a computer system equipped with a circuit protection device, and this computer system is driven by a power supply 10.

The power supply signal output from the power supply 10 is distributed and supplied to a plurality of circuit blocks consisting of the printed boards 41 to 46 through the power supply bus bar 20. The circuit blocks 41, 42, 42, 43, 44-
For each 46, independent overcurrent detection / cutoff circuits 31 to 33 are provided for the respective power input terminals.

The overcurrent detection / cutoff circuits 31 to 33 are
A switching function for turning on / off a power supply signal from the power supply busbar 20 to the corresponding circuit blocks (loads) 41, 42, 43, 44 to 46, an overcurrent detection function for detecting an overcurrent state of a supply current value, and each An error derivation function for deriving an error state signal from a corresponding circuit block is provided, and a power-on / off command signal for operating the switching function is given from the power system control unit 50, and An overcurrent state determination signal obtained by the overcurrent detection function and a current cutoff condition establishment determination signal based on the error state signal obtained by the error derivation function are given to the power system control unit 50.

The power supply system control unit 50 controls ON / OFF of the power supply 10 itself and detects each overcurrent.
The power on / off control is performed for the shutoff circuits 31 to 33. This power on / off control is performed in accordance with the operation of a main power switch (not shown) and from the overcurrent detection / shutdown circuits 31 to 33. It may be performed based on a signal for determining whether or not the current is cut off.

Here, each of the above-mentioned overcurrent detection / cutoff circuits 3
For 1, 32, and 33, the error signal and the error information saving end associated with the operation error of each circuit block 41, 42, 43, 44 to 46 are completed via the corresponding load error derivation lines 41a, 42a, 44a. The signal is derived.

FIG. 2 shows the internal structure of the overcurrent detection / cutoff circuits 31 to 33 in the computer system, which is a DC supplied from the power supply line 311 on the power supply bus bar 20 side.
The power signal is a power transistor 301 and a resistor 302.
Is output to the power line 312 on the load side via.

The power transistor 301 turns on / off a current to / from the load side, and ON / OFF control of the power transistor 301 is given through a signal line 320 from the power supply system controller 50.
Transistor control circuit 30 based on N / OFF command signal
3 through 3.

The resistor 302 captures the supply current to the load side as a voltage through the voltage detection lines 313 and 314. The supply voltage captured through the voltage detection lines 313 and 314 passes through the A / D converter 307. It is converted into a digital value at regular intervals, and is updated and held in the register 308 via the data line 315. The digital voltage data corresponding to the load-side supply current held in the register 308 is given to the alarm determination circuit 305 and the limit determination circuit 306 via the data line 316.

The alarm judging circuit 305 is based on the digital voltage data given from the register 308.
The "alarm" signal output from the alarm determination circuit 305 is determined by determining that the load-side supply current has exceeded a predetermined alarm value (first overcurrent value). It is given to the cutoff condition determination circuit 304 via the alarm line 317.

The limit judging circuit 306 is based on the digital voltage data given from the register 308.
This limit determination circuit 30 determines that the load-side supply current has exceeded a limit value (second overcurrent value) higher than a predetermined alarm value and outputs a "limit" signal.
The “limit” signal output from 6 is applied to the cutoff condition determination circuit 304 via the limit line 318.

Here, the alarm value (first overcurrent value) of the load-side supply current is set to an overcurrent value (for example, steady current + 3 A) to the extent that no major damage is immediately caused to the load-side circuit, and The limit value (second overcurrent value) is set to an overcurrent value (for example, a steady current +5 A) at which large damage is immediately caused to the load side circuit, and the respective overcurrent values are set to the alarm determination circuit 305. And limit determination circuit 30
6 is arbitrarily set by the digital variable switches respectively provided.

An error signal associated with the error operation of the load side circuit is given to the cutoff condition judging circuit 304 via the first load error derivation line 321, and via the second load error derivation line 322. An evacuation completion signal of error information accompanying the error operation of the load side circuit is given.

The cutoff condition judging circuit 304 outputs the respective overcurrent judgment results by the alarm judging circuit 305 and the limit judging circuit 306 and the respective errors obtained from the first load error derivation line 321 and the second load error derivation line 322. Based on the state derivation result, a condition determination is made as to whether to interrupt the current supply to the load or to give a malfunction notification of overcurrent detection. The cutoff condition determination signal from the cutoff condition determination circuit 304 or the malfunction condition determination is performed. The signal is given to the power system control unit 50 via the condition determination notification line 319.

Here, the power supply system control unit 50 outputs an OFF command signal for the power transistor 301 to the transistor control circuit 303 when a cutoff condition judgment signal is given from the cutoff condition judgment circuit 304, and When the malfunction condition determination signal is given, the malfunction notification of the overcurrent detection is given through the notifying means such as a display and a voice not shown. Next, the operation of the computer system including the circuit protection device having the above configuration will be described.

First, to operate the computer system,
When a main power switch (not shown) is operated, the power supply system control unit 50 turns on the power supply 10 and the transistor control circuit 30 of each of the overcurrent detection / cutoff circuits 31 to 33.
3 is sequentially supplied with the power-on command signal via the signal line 320, whereby the power transistor 301 is held in the ON state, and the power-source-side power line 31
The power supply signal given from 1 is the power transistor 3
01 and resistor 302, and load side power supply line 312
Through the corresponding circuit blocks 41, 42, 43, 4
4 to 46.

The load side circuit blocks 41, 42, 4
3, the voltage detection lines 313 and 314 derived from both ends of the resistor 302 in each of the overcurrent detection / cutoff circuits 31 to 33 are supplied with a voltage proportional to the supply current to the load side circuit. This voltage signal is obtained and converted into a digital value by the A / D converter 307 at regular intervals, updated and held in the register 308, and at the same time given to the alarm determination circuit 305 and the limit determination circuit 306.

Here, for example, when an abnormality occurs inside the load side electronic circuit and the current value supplied through the transistor 301 and the resistor 302 exceeds the steady current +3 A, that is, the alarm value (first overcurrent value). , Alarm determination circuit 305
"Alarm" signal is given to the cutoff condition determination circuit 304 from the above, and an operation error accompanying the abnormality occurs in the load side electronic circuit, and the error signal is also determined via the first load error derivation line 321. Provided to circuit 304.

At this time, in the load side electronic circuit, error information saving processing is performed as a normal processing in the computer system. In addition to the above-mentioned "alarm" signal and error signal, this error information saving completion signal is also added. Is also given to the cutoff condition determination circuit 304 via the second load error derivation line 322.

Then, the cutoff condition judgment circuit 304 judges whether or not the current supply cutoff condition for the load side (No. 1) is satisfied, and the cutoff condition judgment signal is given to the power supply system control unit 50. In the system control unit 50, in order to prevent damage to the load side circuit due to overcurrent of about the alarm value, the power transistor 301 is supplied to the transistor control circuit 303 of the overcurrent detection / cutoff circuit to which the cutoff condition determination signal is output. OFF command signal is given, and the current supply to the load side electronic circuit is cut off.

In this case, since the load current is cut off after the error information saving processing in the load side electronic circuit is completed, it is difficult to eliminate the error information later when the cause of the abnormality is clarified. I will never come.

On the other hand, for example, an abnormality different from the above occurs inside the electronic circuit on the load side, and the supply current value on the load side becomes the steady current +
5A, that is, when the limit value (second overcurrent value) is exceeded, the alarm determination circuit 3 is notified to the cutoff condition determination circuit 304.
From 05, the "alarm" signal is the limit judgment circuit 30
A "limit" signal is given from 6 and an operation error accompanying the abnormality occurs in the load side electronic circuit, and the error signal is also the first load error derivation line 321.
Is supplied to the cutoff condition determination circuit 304 via.

Then, the cutoff condition judgment circuit 304 judges whether or not the current supply cutoff condition (part 2) for the load side is satisfied, and the cutoff condition judgment signal is given to the power supply system control unit 50. In the system control unit 50, in order to minimize damage to the load side circuit due to the overcurrent reaching the limit value, the power transistor is supplied to the transistor control circuit 303 of the overcurrent detection / cutoff circuit to which the cutoff condition determination signal is output. The OFF command signal of 301 is given, and the current supply to the load side electronic circuit is cut off. In this case, since the supply current to the load side circuit has increased to the limit value, the circuit protection by current interruption is prioritized over the error information saving process.

Here, the judgment result of the above-mentioned current interruption condition is determined by using the judgment result of the overcurrent state for the load side electronic circuit and the derivation result of the error state signal in the load side electronic circuit. The reason is,
For example, when an overcurrent flows due to a short circuit of the electronic circuit, the function of the electronic circuit cannot be normal,
It utilizes the property that some operation error is detected in the circuit at the same time when overcurrent occurs.
By using the information of the two systems associated with the overcurrent as the condition determination element, for example, an erroneous overcurrent state occurs due to a failure of the A / D converter 307, the register 308, or the alarm determination circuit 305 or the limit determination circuit 306. Even if the load side electronic circuit is not interrupted, the reliability of the circuit interruption due to the detection of overcurrent is ensured.

On the other hand, even if the "alarm" signal from the alarm determination circuit 305 and the "limit" signal from the limit determination circuit 306 are both supplied to the cutoff condition determination circuit 304, the first load error derivation line 321 If the error signal is not derived, and the "alarm" signal from the alarm determination circuit 305, or
When only one of the “limit” signals from the limit determination circuit 306 is given to the cutoff condition determination circuit 304,
In any case, the A / D converter 307 and the register 308, or the alarm determination circuit 305 and the limit determination circuit 30.
6 is determined to be a malfunction due to a failure, and the cutoff condition determination circuit 3
From 04, an "error" signal as a malfunction condition determination is given to the power supply system control unit 50.

As a result, in the power supply system control unit 50, the fact that a failure has occurred in the overcurrent detection / interruption circuit to which the above-mentioned "error" signal is given is notified by the system administrator through the notifying means such as display and voice not shown. And maintenance personnel will be notified.

Therefore, according to the circuit protection device having the above configuration, the voltage proportional to the current supplied to the load side circuit, which is obtained by the resistor 302 interposed in the load side power supply line 312, is supplied via the A / D converter 307. An alarm determination circuit 305 for converting the digital data into the digital data and holding the same in the register 308 and determining whether the load-side supply current exceeds an alarm value higher than the steady-state current and a limit value for the load-side supply current higher than the alarm value. Overcurrent determination result in each of the limit determination circuits 306 for determining that the load has exceeded the limit, a first load error derivation line 321 for deriving an operation error signal of the load side circuit, and a second load error for deriving a save end signal of error information. Based on the error state derivation result from each derivation line 322, the cutoff condition determination circuit 304
The condition of the current interruption is judged by the power supply system control unit 5
Since the OFF command signal of the power transistor 301 is given from 0 to the transistor control circuit 303 to cut off the current supply from the power supply line 311 on the power supply side, the circuit is cut off by overcurrent detection without the risk of malfunction. Even if this overcurrent detection / interruption circuit is individually installed for each divided module, reliable reliability can be obtained and fine circuit protection can be performed.

As a result, even when a large power supply is provided in advance in consideration of the expansion of the system configuration, the circuit protection by the reliable overcurrent detection and the current interruption can be performed from the small system configuration to the large system configuration. It will be possible.

In the above embodiment, the overcurrent detection / cutoff circuits 31 to 33 are installed for arbitrarily divided modules or printed boards, and the respective currents can be cut off by independent overcurrent detection. When an individual module or printed board fails, only the failed module or printed board can be easily replaced while online.

[0043]

As described above, according to the present invention, there is provided a closing / closing circuit which is provided between the power supply and the load side electronic circuit and turns on / off the power supply signal in accordance with a command from the power supply system controller. A current detecting means for detecting a current value of a power supply signal supplied to the load side circuit, and a first overcurrent value whose load side supply current value detected by the current detecting means is higher than its steady current value. A first overcurrent determination means for determining that the current has exceeded the second overcurrent determination means for determining that the load side supply current value detected by the current detection means has exceeded a second overcurrent value higher than the first overcurrent value. Overcurrent determining means, first error deriving means for deriving an error signal associated with the operation error of the load side circuit, and second error deriving means for deriving a save end signal of error information associated with the operation error of the load side circuit. And the first overcurrent The current interruption condition for the load side circuit is determined based on the respective overcurrent determination results by the determination means and the second overcurrent determination means and the error state derivation results by the first error derivation means and the second error derivation means. Since the power supply system control unit is configured to include a cutoff condition determination unit that issues a power supply signal cutoff command to the turning on / off circuit, in the case where a larger power supply is provided in consideration of system configuration expansion. However, there is no fear of malfunction due to an abnormality that occurs on the load side, and reliable overcurrent detection becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a computer system including a circuit protection device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an internal configuration of an overcurrent detection / interruption circuit in a computer system including the circuit protection device.

[Explanation of symbols]

10 ... Power supply, 20 ... Power supply busbar, 31-33 ... Overcurrent detection / interruption circuit, 41-46 ... Printed board (circuit block), 41a, 42a, 44a ... Load error derivation line, 50 ... Power supply system control section, 301 ... power transistor, 302 ... resistor, 303 ... transistor control circuit, 3
04 ... Shutdown condition judging circuit, 305 ... Alarm judging circuit,
306 ... Limit judgment circuit, 307 ... A / D converter, 3
08 ... Register, 311, 312 ... Power supply line, 31
3, 314 ... Voltage detection line, 315, 316 ... Data line, 317 ... Alarm line, 318 ... Limit line, 319 ... Condition determination notification line, 320 ... Signal line, 321 ... First load error derivation line, 322 ... Second
Load error derivation line.

Claims (1)

[Claims] 1. A circuit protection device provided between a power source and an electronic circuit on the load side, wherein the circuit on the load side is provided with an on / off circuit for turning on / off the power signal according to a command from a power system control unit. A current detecting means for detecting a current value of a power supply signal to be supplied, and a first judging means for judging that a load side supply current value detected by the current detecting means exceeds a first overcurrent value higher than its steady current value. An overcurrent determining means, a second overcurrent determining means for determining that the load-side supply current value detected by the current detecting means exceeds a second overcurrent value higher than the first overcurrent value, and the load First error deriving means for deriving an error signal associated with the operation error of the side circuit, second error deriving means for deriving a save end signal of error information associated with the operation error of the load side circuit, and the first overcurrent determination Means And the second overcurrent determination means, the respective overcurrent determination results, and the error state derivation results by the first error derivation means and the second error derivation means, respectively. A circuit protection device, comprising: a cutoff condition determination means for making a power supply signal cutoff command from the power supply system control unit to the closing / cutting circuit.