JP2012088181A - Inspection device for overcurrent detection cutoff circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm an operation of a current detection cutoff circuit installed on a power feeding path of each power source without damaging a computer to be an inspection object in the computer including a plurality of power sources.SOLUTION: An inspection device inspects the overcurrent detection cutoff circuit in the computer including: the plurality of power sources having different output voltage; and the overcurrent detection cutoff circuits for monitoring current amount flowing in the power feeding path corresponding to each power source to cut off current in the power feeding path. The inspection device includes: an electronic load device for supplying current instead of load of each power source when performing an operation test of the overcurrent detection cutoff circuit; a relay circuit interposed between each power feeding path corresponding to each power source and the electronic load device; and a relay control circuit for connecting the power feeding path having the overcurrent detection cutoff circuit to be a test object and the electronic load device by exclusively switching the relay circuit.

Description

  The present invention relates to an inspection apparatus for an overcurrent detection interruption circuit, and more particularly to an inspection apparatus for an overcurrent detection interruption circuit installed on a power supply path of each power supply type in a computer having a plurality of power supply types having different output voltages.

  In computers, power supply paths to loads that consume power, such as LSIs and memories, are designed with sufficient power so that the load and power supply paths will not generate heat and burn out even if they exceed the maximum power required by the load. ing. Further, an overcurrent detection / cutoff circuit is provided in the power supply or on the power supply path in order to prevent the load and the power supply path from burning out when a design value abnormal current flows (hereinafter referred to as an overcurrent). The overcurrent detection cutoff circuit is usually composed of a melting fuse, a breaker, and an electronic circuit. Among them, the overcurrent detection cutoff circuit, which consists of an electronic circuit, monitors the amount of current to the load on the power supply system path and shuts off the power supply when the amount of current reaches the overcurrent. Prevents burning.

  However, if the overcurrent detection cutoff circuit has failed, the power supply path cannot be interrupted even if an overcurrent flows, and the overcurrent continues to flow, causing the load and power supply path to burn out, resulting in a serious accident. There is a risk. Therefore, it is necessary to confirm that the overcurrent detection cutoff circuit can detect overcurrent and cut off the power supply.

  As a method of inspecting the overcurrent detection cutoff circuit, it is difficult to cause the overcurrent necessary for the inspection of the overcurrent detection cutoff circuit in normal operation using a load such as an actual LSI or memory. As an alternative to this, there is a method of connecting a resistor or an electronic load device and supplying a current necessary for inspection.

  In the method using a resistor, it is possible to flow current with a relatively simple circuit configuration, but current control becomes difficult when the output voltage of the power source to be inspected is low or the flowed current is large. On the other hand, in the method using an electronic load, a voltage and a current can be used within a certain range, and the value of the flowing current can be easily controlled.

  For example, in Patent Document 1, an AC power source, a load, and the like can be added to a power source to be inspected without using a relay, and a conventional high voltage / high current relay and a signal conversion box are not required. A power supply inspection apparatus is disclosed in which one AC power supply is directly connected to a plurality of connectors provided for each model of power supply to be inspected and a plurality of loads are selectively connected directly.

JP 2004-20413 A

  When inspecting the overcurrent detection cutoff circuit, connect an electronic load device instead of the actual load to the power supply path to perform the inspection, and send an electronic load with a larger current than the overcurrent detection cutoff circuit detects the overcurrent. It is confirmed that the overcurrent detection cutoff circuit is operating correctly by checking that the power supply path is cut off when the device is pulled in.

In the power supply inspection device for a single output power source described in Patent Document 1, an electronic load device is used to flow a current from the power source to be inspected to the inspection device. However, in the conventional device, one electronic load device is required for checking the overcurrent detection cutoff circuit of one power supply path.
Therefore, when it is assumed that the operation of each overcurrent detection cutoff circuit is confirmed for a computer with a plurality of power source types, the number of electronic load devices is required for the number of power supply paths, so the scale of the inspection device is large. There is a problem that the cost increases.

  The present invention relates to an overcurrent detection cutoff in a computer having a plurality of power supplies, which can check the operation of a current detection cutoff circuit installed on the power supply path of each power supply without damaging the computer to be inspected. An object of the present invention is to provide a circuit inspection apparatus.

The present invention preferably monitors an amount of current that flows through a plurality of power supplies having different output voltages and a power supply path corresponding to each power supply, and includes an overcurrent detection cutoff circuit that cuts off the current in the power supply path. An inspection device for a current detection cutoff circuit,
In the operation test of the overcurrent detection cutoff circuit, an electronic load device that supplies current instead of the load of the power source, a relay circuit that is interposed between each power supply path corresponding to the power source and the electronic load device, An inspection apparatus for an overcurrent detection cutoff circuit, comprising: a power supply path having the overcurrent detection cutoff circuit to be tested; and a relay control circuit that connects the electronic load device by switching the relay circuit exclusively. Configured as

In a preferred example, the relay control circuit controls an exclusive circuit and a timing delay circuit having a reset function between the relay circuit so as to delay only a time during which the selected relay circuit operates. Thus, it is possible to prevent a plurality of power supply paths from being simultaneously selected when switching the relay connection.
In a preferred example, the operation test of each overcurrent detection cutoff circuit of each power supply path having a different output voltage is performed by one electronic load device.

  According to the present invention, in a computer having a plurality of power supplies, an operation test of an overcurrent detection cutoff circuit is performed without reducing the number of electronic load devices to reduce the number of electronic load devices and damaging the computer. be able to.

The figure which shows the structure of the inspection apparatus of the overcurrent detection interruption | blocking circuit of the computer by one Embodiment. The figure which shows the structure of the relay control circuit in the inspection apparatus of the overcurrent detection interruption | blocking circuit in one Embodiment (Example 1). The figure which shows the structure of the relay control circuit in the inspection apparatus of the overcurrent detection interruption | blocking circuit in one Embodiment (Example 2). 9 is a timing chart illustrating an operation of a reset IC according to an embodiment (Example 2). The timing chart which shows the behavior of the control line in the relay control circuit in one embodiment (Example 2). 6 is a timing chart illustrating the behavior of a control line and a relay circuit in a relay control circuit when switching a relay circuit according to an embodiment (Example 1). 9 is a timing chart illustrating the behavior of a control line and a relay circuit in a relay control circuit when the relay circuit is switched according to an embodiment (Example 2).

  Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of an inspection apparatus for an overcurrent detection cutoff circuit.
Using the inspection device 2 that is characteristic of the present invention, a plurality of overcurrent detection cutoff circuits of the computer 1 that is the device to be inspected are inspected.
The computer 1 includes a plurality of power supplies 101 to 105, overcurrent detection cutoff circuits 111 to 115, power supply paths 121 to 126, and terminals 131 to 136. Each power supply 101-105 outputs a different voltage. Loads such as LSI and memory for operating the computer are actually connected to the terminals 131 to 136.

The plurality of overcurrent detection cutoff circuits 111 to 115 installed on the power supply paths 121 to 126 connecting the power supplies 101 to 105 and the terminals 131 to 135 monitor the amount of current flowing through the respective power supply paths, and the amount of current is When the maximum amount of current that can be used is reached, the current of the power supply paths 121 to 126 is cut off, thereby preventing the computer that is the device to be inspected from being burned out.
In the operation test of the overcurrent detection cutoff circuit, the operation test is performed by connecting the inspection device 2 to the terminals 131 to 136 to which the LSI and the memory are connected.

The inspection device 2 includes relay circuits 151 to 155, a relay control circuit 5, an electronic load device 4, a voltage monitoring circuit 6, and terminals 181 to 186.
The electronic load device 4 is used to supply a current instead of a load of a power source in an operation test of the overcurrent detection cutoff circuit. The electronic load device supports a wide range of voltages and currents, and can easily control the current value to flow. Therefore, it is possible to cope with an operation test of the overcurrent detection cutoff circuit of a plurality of power supply paths having different output voltages with one electronic load device.
The relay circuit 5 connects the power supply path to be tested and the electronic load device 4 by a control signal from the personal computer 3.

The terminals 181 to 186 and the relay circuits 151 to 155 are connected by cables 191 to 196, and similarly, the electronic load device 4 is also connected by the cable 147 from the relay circuits 151 to 156. The voltage monitoring circuit 6 is connected to terminals 181 to 186 through cables 161 to 162. The electronic load device 4, the relay control circuit 5, and the voltage monitoring circuit 6 are connected by control lines 171 to 173 so that they can be controlled from the external personal computer 3.
The computer 1 and the inspection device 2 are connected by connecting the terminals 131 to 136 on the computer 1 and the terminals 181 to 186 on the inspection device 2 with cables 191 to 196.

  When the inspection device 2 performs an operation test of the overcurrent detection cutoff circuits 111 to 115 on the computer 1, first, the relay control circuit 5 is operated from the personal computer 3 via the control line 172, and the power supply path and the electronic device to be tested are operated. After controlling the relay circuits 151 to 155 so that the load device 4 is connected, the power source to be tested is operated, and the electronic load device 4 is operated to supply current.

  For example, when the relay circuit 151 is selected, current flows from the power source 101 through the overcurrent detection cutoff circuit 111 and the power feeding path 121. The current that has entered the inspection device 2 via the cable 191 passes through the cable 141 and flows to the relay circuit 151, passes through the relay circuit 151 and the cable 147, and flows to the electronic load device 4. The return current passes from the electronic load device 4 through the cable 146 and the cable 196 and returns to the computer 1. Then, it passes through the power supply path 126 and the ground 7 on the computer 1 and flows to the power source 101.

  The electronic load device 4 flows a current smaller than the current value at which the overcurrent detection cutoff circuit detects the overcurrent. At that time, it is confirmed that the voltage value of the voltage monitoring circuit 6 is not less than a certain value that the overcurrent detection cutoff circuit does not cut off the power feeding path. Next, the electronic load device draws a current larger than the current value at which the overcurrent detection cutoff circuit detects the overcurrent. At this time, it is confirmed that the voltage value of the voltage monitoring circuit 6 is below a certain value that the overcurrent detection cutoff circuit cuts off the power feeding path.

  When the operation test of the first overcurrent detection cutoff circuit (eg 111) is completed, the relay circuit 5 is switched to connect the overcurrent detection cutoff circuit (eg 112) to be inspected next and the electronic load device 4. By repeating this, the inspection device 2 can perform the operation test of all the overcurrent detection cutoff circuits 111 to 115 in the computer 1.

Next, the configuration of the relay control circuit 5 in the first embodiment will be described with reference to FIG.
The relay control circuit 5 is configured by connecting an I / O register 201 to each of the relay circuits 151 to 155 via control lines 211 to 215. The I / O register 201 is controlled by the control line 172 from the external personal computer 3, and turns on the control lines 211 to 215. The I / O register 201 can simultaneously turn on two or more relay circuits.

  Since the relay circuits 151 to 155 are mechanical relays, the response speed is slow, and it takes time to switch on / off. Therefore, for example, when switching the relay circuit 151 from on to off when the relay circuit 151 is switched on from the state in which the relay circuit 151 is on, the operation of turning the relay circuit 152 off from on is performed simultaneously. There is a possibility that the two relay circuits 151 and 152 are simultaneously turned on.

  For example, referring to the timing chart showing the behavior of the control line and the relay circuit when the selection is switched from the relay circuit 153 to the relay circuit 154 shown in FIG. 6, SEL3 (213) is switched from on to off. SEL4 (214) is switched from off to on at the same time. Since the relay circuit 5 has a slow response speed and the response time varies depending on each relay circuit, there is a time 601 in which the relay circuits 153 and 154 are simultaneously turned on.

  When the relay circuit is turned on at the same time, the two power supply paths are connected via the relay circuit. Since each power supply has a different output voltage, an unexpected voltage is applied to the power supply path or a reverse current flows due to the flow of current from the other power supply due to the connection of the two power supply paths. The computer 1 may be damaged. Therefore, the relay circuit 5 is controlled by software provided in the personal computer 3 so that the relay circuit is exclusive and the response speed of the relay circuit is taken into consideration, and two or more relay circuits are not turned on at the same time.

FIG. 3 shows a configuration of the relay control circuit 5 according to the second embodiment.
In FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals. The relay control circuit 5 includes an I / O register 201, an exclusive selection circuit 301, and reset ICs 311 to 315. A control line 172 connected to the external personal computer 3 is connected to the I / O register 201. Control lines SEL1 to SEL5 (211 to 215) and ENABLE (341) extending from the I / O register are connected to the exclusive selection circuit 301. Exclusive selection circuit 301 and reset ICs 311 to 315 are connected by control lines MR_N1 to MR_N5 (321 to 325), and relay circuits 151 to 155 and reset ICs 311 to 315 are connected by control lines ON1 to ON5 (331 to 335). .

FIG. 5 is a timing chart showing the behavior of the control lines MR_N1 to MR_N5 (321 to 325) and ON1 to ON5 (331 to 335) when the control lines SEL1 to SEL5 (211 to 215) and ENABLE (341) are operated. is there.
To control the exclusive selection circuit 301, first, the I / O register 201 is operated by the control line 172, and one of the control lines SEL1 to SEL5 is turned on. Next, the control lines MR_N1 to MR_N5 corresponding to the selected control lines SEL1 to SEL5 are selected by turning on the control line ENABLE341. The exclusive selection circuit 301 does not simultaneously turn on a plurality of control lines MR_N1 to MR_N5 even when the control line ENABLE is turned on while a plurality of control lines SEL1 to SEL5 are erroneously turned on at the same time.
For example, referring to the behavior of the control line when SEL2 and SEL5 are turned on at the same time, as shown in Figure 5, while SEL2 and SEL5 are turned on at the same time (502), the corresponding MR_N1 and MR_N2 are both turned on. Not done (504).

  Next, the reset IC will be described. FIG. 4 is a timing chart showing the behavior of signals of the MR_N pin and the RESET_N pin. The reset ICs 311 to 315 have MR_N and RESET_N pins as input / output pins. The reset IC instantly lowers the RESET_N pin voltage when the MR_N pin voltage falls below a certain threshold, but conversely increases the RESET_N pin voltage after a certain delay when the MR_N pin voltage rises above a certain threshold. To work.

  For example, referring to the behavior of the control line when the operation of selecting the relay circuit 154 from the state where the relay circuit 153 is selected is shown in FIG. Since switching from off to on is simultaneously performed (501), operations of MR_N3 and MR_N4 are also performed (503). However, only the rise time of ON4 is delayed by a certain time by passing through the reset IC (505).

  FIG. 7 is a timing chart showing in more detail the behavior of the control line and the relay circuit when the selection is switched from the relay circuit 153 to the relay circuit 154. Even if SEL3 is switched from ON to OFF and SEL4 is switched from OFF to ON to OFF at the same time, the rise time of ON4 is delayed, so even if the response time of the relay circuit (153 and 154) varies The circuits (153 and 154) are not turned on at the same time.

  According to the relay control circuit 5 of the second embodiment described above, the relay circuit can be prevented from being simultaneously turned on without performing control by software for preventing the relay circuit as in the first embodiment from being simultaneously turned on. be able to.

1: Computer 2: Inspection device 3: PC 4: Electronic load device 5: Relay control circuit
6: Voltage monitoring circuit 7: Ground 101 to 105: Power supply 111 to 115: Current detection cutoff circuit
121-126: Supply path 131-136: Terminal 141-147: Cable 151-155: Relay circuit
161 to 162: Cable 171 to 174: Control line 181 to 186: Terminal 191 to 196: Cable
201: I / O registers 211 to 215: Control line 301: Exclusive selection circuit 311 to 315: Reset IC
321 to 325, 331 to 335, 341: Control lines.

Claims (3)

An overcurrent detection / cutoff circuit inspection apparatus for a computer having a plurality of power supplies having different output voltages and an overcurrent detection / cutoff circuit for monitoring the amount of current flowing through the power feed path corresponding to each power supply and cutting off the current in the power feed path Because
In an operation test of the overcurrent detection cutoff circuit, an electronic load device for supplying a current instead of a load of the power source,
A relay circuit interposed between each power supply path corresponding to the power source and the electronic load device;
An inspection apparatus for an overcurrent detection cutoff circuit, comprising: a power supply path having the overcurrent detection cutoff circuit to be tested; and a relay control circuit that connects the electronic load device by switching the relay circuit exclusively. . In the inspection apparatus of the overcurrent detection cutoff circuit according to claim 1,
The relay control circuit connects an exclusive circuit and a timing delay circuit having a reset function between the relay circuit, and controls so that only the time for which the selected relay circuit operates is delayed. 2. The overcurrent detection cutoff circuit inspection apparatus according to claim 1, wherein a plurality of power supply paths are prevented from being simultaneously selected at the time of connection switching. 3. The overcurrent detection / breaking circuit inspection apparatus according to claim 1 or 2, wherein an operation test of each overcurrent detection / breaking circuit of each power supply path having a different output voltage is performed by one electronic load device.

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