JPH05146038A - Interface power supply monitoring device - Google Patents

Abstract

PURPOSE:To enable a failure of a terminator power supply system including blow-off of a fuse which is inserted to a power supply line to the terminator to be detected automatically and immediately instead of visual confirmation. CONSTITUTION:A title item is provided with a voltage monitoring equipment 36 for detecting a failure by monitoring voltage between points A and B at both terminals of a fuse 32. a switch 37 for turning on/off power supply to a terminator power supply line C0, and a switch selection circuit 38 for turning on/off the switch 37 according to an instruction from the voltage monitoring equipment 36. Then. when a failure in terms of the interface standard is detected by the voltage monitoring equipment 36, the failure is reported to an outside and at the same time the switch selection circuit 38 is instructed to turn off the ON state of the switch 37 if it is ON.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface power supply monitoring device used in a device connectable through an interface cable.

[0002]

2. Description of the Related Art Conventionally, a pull-up terminator (termination resistance circuit) is connected to the end of a signal transmission line in each device that transmits and receives through an interface cable such as a SCSI cable.

FIG. 3 is a diagram showing the configuration of a conventional terminator power supply system. In the figure, 10 and 20 are devices connected via an interface line C, respectively. In the interface line C, C0 is a terminator power supply line for supplying power to the terminators 11 and 21 of the devices 10 and 20, C1 is a signal transmission line, and the devices 10 and 20 are connected to the terminator power supply line C0. Power can be supplied from each other. Fuses 12 and 22 as overcurrent protection means are provided at both ends of the terminator power supply line C0.
And diodes 13 and 23 for preventing backflow are inserted. In addition, 14 and 24 are drivers, and 15 and 25 are receivers.

However, in such a terminator power supply system, if the terminator power supply line C0
In most cases, even if the fuses 12 and 22 inserted in the fuse are blown, the situation is not noticed until an abnormality is detected by actually attempting signal transmission on the devices 10 and 20,
This could be one of the causes of reducing the reliability of the system.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem and is caused by visual confirmation of an abnormality in the terminator power supply system including disconnection of a fuse inserted in the power line to the terminator. It is an object of the present invention to provide an interface power supply monitoring device that can automatically and immediately detect and notify the user.

[0006]

In order to achieve the above-mentioned object, an interface power supply monitoring device of the present invention is provided.
An interface for supplying power to the terminator connected to the end of the interface line from each device connected via the interface line, and for supplying power to each other from the device to the terminator. A power source line; a fuse inserted in the power source line; and a monitoring unit that monitors the voltage across the fuse to detect an abnormality and, when an abnormality is detected, notifies the outside to that effect. ing.

[0007]

In the interface power supply monitoring device of the present invention, the monitoring means monitors the voltage across the fuses inserted in the power supply lines for mutually supplying power to the terminator to detect an abnormality, and the abnormality is detected. When it is detected, the fact is notified to the outside, so it is possible to automatically and immediately detect the abnormality of the terminator power supply system such as blown fuse or cable abnormality, and notify the user. it can.

[0008]

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

FIG. 1 is a diagram for explaining the configuration of an interface power supply monitoring apparatus according to an embodiment of the present invention. In the figure, reference numerals 30 and 40 denote devices such as a computer and other peripheral devices connected through an interface line C. In the interface line C, C0 is a terminator power supply line for supplying power to the terminators (termination resistance circuits) 31 and 41 of the devices 30 and 40, C1 is a signal transmission line, and the terminator power supply line C0 is connected to the terminator power supply line C0. Each device 3
The power can be supplied to each other from 0 and 40. Fuses 32 and 42 as overcurrent protection means and diodes 33 and 43 for preventing backflow are inserted at both ends of the terminator power supply line C0. Note that 34 and 44 are drivers, and 35 and 45 are receivers.

Further, in this interface power supply monitoring device, the A side of both ends of the fuse 32 is provided on the device side of 30.
A voltage monitor 36 for monitoring the voltages at the points B and B to detect an abnormality, a switch 37 for switching on / off the power supply to the terminator power supply line C0, and a switch according to an instruction from the voltage monitor 36. A switch changeover circuit 38 for turning on / off 37 is provided.

Next, the operation of this interface power supply monitoring device will be described with reference to the flowchart of FIG. It is assumed that the switch 37 is off in the initial state. The power supply to the terminator power supply line C0 is finally performed mutually by the respective devices 30 and 40, but in this device, the power supply to the terminator is started at the timing when the power supply to either of the devices 30 and 40 is started. Start system monitoring operation. First, the case where the power of the device 40 is turned on first will be described.

First, the voltage monitor 36 checks the voltage at point B,
This B point voltage matches the interface standard,
In other words, it is checked whether the terminator power supply is within the normal level range (step 201).

Here, when the fuse 41 of the terminator power supply system, for example, the device 40 is blown or the interface line C is abnormal, the voltage abnormality at the point B is detected, and the voltage monitor 36 detects this. Notify the central processing unit (not shown) of the device 30 (step 20).
2). Upon receiving this notification, the central processing unit notifies the user of that fact through a display device such as a display.

If the voltage at the point B is normal, then the voltage level of the voltage monitor 36 is High according to the interface standard.
It is checked whether the level or the low level is met (step 203).

In this case, it is determined that the voltage at point B is at the high level. If the B point voltage is at the high level, the voltage monitor 36 next checks the voltage level at the A point,
Judge whether it is a high level or a low level (step 20)
4).

If the voltage at the point A is at a low level, the voltage monitor 36 considers that the fuse 31 of the device 30 is blown and notifies the central processing unit of the fuse abnormality (step 205).

If the voltage at the point A is at a high level, the voltage monitor 36 considers that the fuse 31 has no abnormality and instructs the switch switching circuit 38 to turn on the switch 37. As a result, the switch 37 is turned on and the device 3
Power from 0 is applied to the terminator power supply line C0 (step 206). Thereafter, the voltage monitor 36 notifies the central processing unit that there is no abnormality (step 20).
7).

Next, the case where the power of the device 40 is turned on later will be described.

When the voltage monitor 36 determines in step 202 that the voltage at the point B is at a low level, it instructs the switch switching circuit 38 to turn on the switch 37, thereby turning on the switch 37 and causing the device 30 to turn on. The power supply to the terminator power supply line C0 is started (step 208).

Subsequently, the voltage monitor 36 again checks the voltage at the point B to determine whether the voltage at the point B is at the HIGH level or the Low level (step 209).
Considering that the fuse 31 of 0 is blown, the switch switching circuit 38 is instructed to turn off the switch 37 (step 210), and the central processing unit is notified that the fuse 31 is blown (step 205). ..

Thus, according to the interface power supply monitoring apparatus of this embodiment, the fact that the fuse 31 inserted in the terminator power supply line C0 is blown or that the terminator power supply system is abnormal is detected by the fuse 31. It is possible to automatically detect the voltage by monitoring the voltage at both ends and notify the user accordingly.

[0022]

As described above, according to the interface power supply monitoring device of the present invention, the voltage across the fuses inserted in the power supply line for mutually supplying power to the terminator is monitored to detect abnormalities. If it is detected, it can be notified to the user by notifying the outside by detecting the abnormality of the terminator power supply system including the blown fuse automatically and promptly regardless of the visual confirmation. ..

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining a configuration of an interface power supply monitoring device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation flow of the interface power supply monitoring device of FIG.

FIG. 3 is a circuit diagram showing a configuration of a conventional interface power supply system.

[Explanation of symbols]

30, 40 ... Device, 31, 41 ... Terminator, 32,
42 ... Fuse, 33, 43 ... Diode, 34, 44
... driver, 35, 45 ... receiver, 36 ... voltage monitor, 37 ... switch, 38 ... switch switching circuit, C ... interface line, C0 ... terminator power supply line, C1 ... signal transmission line.

Claims (1)

[Claims] 1. An interface in which power is mutually supplied from each device connected via the interface line to a terminator connected to the end of the interface line, and the power is mutually supplied from each device to the terminator. A power supply line for supplying to the power supply line, a fuse inserted in the power supply line, and detecting an abnormality by monitoring the voltage across the fuse.
An interface power supply monitoring device, comprising: a monitoring means for notifying the outside when an abnormality is detected.