JPH0568322A - 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 307 through an A/D converter from a resistor 302, and by an overcurrent judging circuit 305, it is judged that the supply current on the load side has exceeded the overcurrent monitor value higher than the stationary current, and only when the operation error signal of the circuit on load side is led out by a load error lead-out line 328, the materialization of the condition of the current break is judged in a break condition judging circuit 304. And the off signal of a power transistor 301 is given from a power system controller 50 to a transistor control circuit 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. An overcurrent judging means for judging that a preset overcurrent monitoring value higher than the current value is exceeded, a load error deriving means for deriving an error signal accompanying an operation error of the load side circuit, and the overcurrent judging means. Is performed to determine whether the overcurrent monitoring value is exceeded, and when the load error deriving unit derives an error signal, the power supply system controller issues a power supply signal cutoff command to the closing / closing circuit. And a condition determining means.

[0014]

In other words, the current interruption condition is not satisfied unless the condition elements of the two systems, that is, the overcurrent judgment value excess judgment by the overcurrent judgment means and the error signal derivation state by the load error derivation means are all aligned. Since the power supply signal to the load side circuit is not shut off, reliable and highly reliable circuit protection by overcurrent detection / shutdown can be 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 signal from a corresponding circuit block is provided, and a power supply on / off command signal for operating the switching function is a power supply system control unit 50.
From the above, the current cutoff condition establishment determination signal based on the overcurrent determination signal obtained by the overcurrent detection function and the error signal obtained by the error derivation function is
It is given to the power supply system controller 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, error signals associated with operation errors of the circuit blocks 41, 42, 43 and 44 to 46 are derived via the corresponding load error derivation lines 41a, 42a and 44a.

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

This overcurrent judging circuit 305 judges on the basis of the digital voltage data given from the register 307 that the load side supply current has exceeded a predetermined overcurrent monitoring value and outputs an overcurrent judging signal. Therefore, the overcurrent determination signal output from the overcurrent determination circuit 305 is given to the cutoff condition determination circuit 304 via the overcurrent determination line 317.

Here, the overcurrent monitoring value of the load side supply current is set to an overcurrent value (for example, a steady current +3 A) at which the load side circuit will not be seriously damaged immediately. The monitor value is arbitrarily set by a digital variable switch provided in the overcurrent determination circuit 305. An error signal associated with the error operation of the load side circuit is given to the cutoff condition determination circuit 304 via the load error derivation line 318.

The cutoff condition judging circuit 304, based on the overcurrent judging result by the overcurrent judging circuit 305 and the error signal deriving result from the load error deriving line 318,
The condition determination is made as to whether the current supply to the load is cut off or the malfunction notification for overcurrent detection is issued. The cutoff condition judgment signal or malfunction condition judgment signal from the cutoff condition judgment circuit 304 is a condition judgment notification line. It is given to the power supply system control unit 50 via 319.

Here, the power supply system control section 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, in order 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 is converted to a digital value by the A / D converter 306 at regular intervals, updated and held in the register 307, and simultaneously given to the overcurrent determination circuit 305.

Here, for example, when an abnormality occurs in the load side electronic circuit and the current value supplied through the transistor 301 and the resistor 302 exceeds the steady current + 3A, that is, the overcurrent monitoring value, the overcurrent determination circuit. An overcurrent determination signal is supplied from 305 to the cutoff condition determination circuit 304, and an operation error associated with an abnormality occurs in the load side electronic circuit, so that the error signal also passes through the load error derivation line 318. Given to 304.

Then, the cutoff condition judgment circuit 304 judges whether or not the current supply cutoff condition for the load side is satisfied, and the cutoff condition judgment signal is given to the power supply system control unit 50. Then, in order to prevent damage to the load side circuit due to overcurrent, the power transistor 30 is connected to the transistor control circuit 303 of the overcurrent detection / cutoff circuit in which the cutoff condition determination signal is output.
The OFF command signal of 1 is given, and the current supply to the load side electronic circuit is cut off.

Here, the reason for using the judgment result of the overcurrent state with respect to the load side electronic circuit and the derivation result of the error signal in the load side electronic circuit as the condition judging elements for judging the above current interruption condition That is, when an overcurrent flows due to, for example, a short circuit in the electronic circuit, the function of the electronic circuit cannot be normal, and at the same time when the overcurrent occurs, some operation error is detected in the circuit. By using such two-system information associated with overcurrent as a condition determination element, for example, the A / D converter 306, the register 307, or the overcurrent determination circuit 305 is used. Even if an erroneous overcurrent condition occurs due to a failure, the current to the load side electronic circuit will not be interrupted, and the reliability of circuit interruption due to overcurrent detection will be improved. To the real thing.

On the other hand, if the error signal from the load error derivation line 318 is not derived even when the overcurrent determination signal from the overcurrent determination circuit 305 is given to the cutoff condition determination circuit 304, the A / D converter 306. Or register 307,
Alternatively, it is determined that the malfunction occurs due to a failure of the overcurrent determination circuit 305, and the cutoff condition determination circuit 304 causes the power supply system control unit
An "error" signal as a malfunction condition determination is given to 0.

As a result, in the power supply system control unit 50, the system administrator is informed through the notifying means such as a not-shown display and voice that a failure has occurred in the overcurrent detection / interruption circuit to which the "error" signal is given. 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 passed through the A / D converter 306. Converted to digital data and held in the register 307, the overcurrent determination circuit 30
5 determines that the load-side supply current has exceeded the overcurrent monitoring value higher than the steady-state current, and only when the operation error signal of the load-side circuit is derived by the load error derivation line 318, the cutoff condition determination circuit. Since it is determined in 304 that the current cutoff condition is satisfied, and the power supply system control unit 50 gives an OFF command signal for the power transistor 301 to the transistor control circuit 303, the current supply from the power supply side power supply line 311 is cut off. The circuit can be cut off by overcurrent detection without the risk of malfunction, and even if this overcurrent detection / cutoff circuit is installed individually for each divided module, reliable reliability is obtained and fine-tuned. Circuit protection becomes possible.

As a result, even if a large power supply is provided in advance in consideration of the expansion of the system configuration, circuit protection by reliable overcurrent detection and current interruption can be performed from small system configurations to large system configurations. 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 current cutoff can be performed by independent overcurrent detection in each of them. When an individual module or printed board fails, only the failed module or printed board can be easily replaced while online.

[0037]

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. And a current detection means for detecting the current value of the power supply signal supplied to the load side circuit, and a preset overcurrent in which the load side supply current value detected by this current detection means is higher than its steady current value. Overcurrent determination means for determining that the monitoring value has been exceeded, load error derivation means for deriving an error signal associated with an operation error of the load side circuit, and overcurrent determination value excess determination by the overcurrent determination means. And a disconnection condition determining means for causing the power supply system control unit to issue a power supply signal disconnection command to the closing / interrupting circuit when the error signal is derived by the load error deriving means. Since form was, even when to have a larger power in consideration of the expansion of the system configuration, without fear malfunction to abnormality occurring in the load side, allowing reliable overcurrent detection.

[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 ... Breaking condition judging circuit, 305 ... Overcurrent judging circuit, 3
06 ... A / D converter, 307 ... Register, 311, 31
2 ... power supply line, 313, 314 ... voltage detection line, 3
15, 316 ... Data line, 317 ... Overcurrent determination line, 318 ... Load error derivation line, 319 ... Condition determination notification line, 320 ... Signal 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. Current detection means for detecting the current value of the supplied power supply signal, and it is determined that the load-side supply current value detected by this current detection means exceeds a preset overcurrent monitoring value higher than its steady-state current value. Overcurrent determination means, load error derivation means for deriving an error signal associated with the operation error of the load side circuit, and overcurrent determination value excess determination by the overcurrent determination means, and the load error derivation Disconnection condition determining means for causing the power supply system control unit to issue a power supply signal disconnection command to the closing / interrupting circuit when the error signal is derived by the means. Circuit protection device according to claim.