JPH10124154A - Power circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely protect a power unit and a power line from a failure on the load side and also to prevent a secondary accident that is caused by system malfunction in a power circuit which has plural loads. SOLUTION: Plural load circuits 15 are connected to an output terminal of a power unit 11 that has an overcorrent protective function via their respective overcorrent detecting parts 16. When overcorrect occurs by a short circuit failure, etc., in any of the circuits 15, the overcorrent is detected by the part 16 and an overcurrent detecting signal 18 is sent to a short circuiting circuit 12. The circuit 12 responds to it and short-circuits an output terminal of the unit 11 and a ground. Power supply from the unit 11 that has an overcurrent protective function is stopped by overcurrent caused by the short circuit. By stropping power supply of entire circuits with small current caused by a short circuit failure of a load, each device is protected and the occurrence of a secondary accident is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit, and more particularly to a power supply circuit used for information equipment such as a personal computer.
The present invention relates to a power supply circuit having a power supply device with an overcurrent protection function or a ground protection function.

[0002]

2. Description of the Related Art A conventional power supply circuit used in a personal computer or the like is described in, for example, Japanese Patent Application Laid-Open No. 61-262046. In the power supply circuit described in the publication, a fuse is inserted for each load circuit so that an overcurrent accident caused by a short circuit or the like of each load circuit does not affect the entire system. A configuration is employed in which the fuse is intentionally blown to selectively cut off the load circuit.

[0003] The conventional power supply circuit will be described with reference to FIG. The power supply circuit includes a normal power supply 1 and a commercial power supply 5.
And a plurality of load circuits 7. Normally, the switch 2 is turned on and the bypass switch 4 is turned on to operate by power supply from the power supply device 1. When a short circuit accident occurs in any of the load circuits 7, the output of the power supply device 1 becomes an overcurrent state. The overcurrent detection unit 2 detects this overcurrent state and switches the switch 3 off and the bypass switch 4 on. Thus, the power supply from the commercial power supply 5 is performed to the load 7 via the fuse 6 instead of the power supply from the power supply device 1. Generally, the power supply capacity of the commercial power supply is much larger than the power supply capacity of the power supply device 1. Therefore, a large short-circuit current flows from the commercial power supply 5 to the fuse 6 in which the short-circuit accident has occurred. As a result, the corresponding fuse 6 is blown in a short time, and only the load circuit 7 in which the short circuit has occurred is immediately disconnected from the power supply device 1.

[0004]

In the above conventional power supply circuit, the overcurrent is detected based on the total current on the load side. Therefore, if the overcurrent at the time of a short circuit accident on the load side is smaller than a predetermined value, the overall May not be determined to be in an overcurrent state, and could not completely protect the power supply, the power supply line, and the load circuit.

Further, since only the power supply to the load circuit in which the short-circuit accident has occurred is selectively stopped, in the case of a circuit configuration in which the load circuits influence each other, if another load is operated in this state. May cause unexpected accidents.
For example, in a case where the overall operation is controlled while monitoring the state of the device with a plurality of sensors, the supply of power to another sensor and device is continued while the supply of power to one sensor is stopped. This may cause a malfunction of the system or cause a secondary disaster in the system.

An object of the present invention is to provide a power supply circuit having a power supply device with an overcurrent protection function or a ground protection function for supplying power to a plurality of load circuits. Another object of the present invention is to protect a load reliably and prevent a secondary disaster due to a system malfunction.

[0007]

In order to achieve the above object, a power supply circuit according to the present invention, when detecting an overcurrent at an output terminal that is equal to or greater than a predetermined value, stops the supply of current from the output terminal. A power supply circuit with a protection function, a plurality of load circuits connected to the output terminal, and a plurality of overcurrent detection means disposed between the output terminal and the load circuit corresponding to each load circuit And an overcurrent generating means connected to an output terminal of the power supply circuit, wherein when at least one of the plurality of overcurrent detecting means detects an overcurrent, an overcurrent that is equal to or more than the predetermined value is generated at the output terminal. It is characterized by having.

Also, the power supply circuit of the present invention, in place of the above configuration, has a power supply device with a ground protection function for stopping supply of current from the output terminal when the ground is detected at the output terminal. A plurality of load circuits connected thereto, a plurality of overcurrent detection means disposed between the output terminal and the load circuit corresponding to each load circuit, and connected to an output terminal of the power supply device; At least one of the plurality of overcurrent detection means;
Grounding means for generating a ground at the output terminal when one of the terminals detects an overcurrent, and a ground protection device for stopping current supply from the output terminal when detecting grounding at the output terminal. A power supply device with a function, a plurality of load circuits connected to the output terminal, and a plurality of overcurrent detection means disposed between the output terminal and the load circuit corresponding to each load circuit. A grounding means connected to an output terminal of the power supply device and generating a ground at the output terminal when at least one of the plurality of overcurrent detecting means detects an overcurrent. It is also possible to adopt a configuration that uses

In the power supply circuit of the present invention, when an overcurrent occurs in any one or more of a plurality of loads, a plurality of overcurrent detection means provided corresponding to each load circuit detects the overcurrent, and An overcurrent or ground exceeding a predetermined value is generated at the output terminal of the power supply device. The power supply unit is provided with an overcurrent protection function or a ground protection function.
The power supply stops supplying power altogether. Therefore, the power supply device and the power supply line are protected from an accident on the load side, and there is no possibility of causing a secondary disaster of the system.

In the power supply circuit according to the present invention, the power supply having the overcurrent protection function or the ground protection function may be any power supply that supplies DC or AC, but is preferably used as a DC power supply for a computer system, for example. Adopted. Each load circuit may be a single load composed of a single component or a load circuit composed of a set of components.

[0011] Further, it does not matter whether the overcurrent detection unit uses an overcurrent detection method. The overcurrent generating means or the ground generating means,
For example, it may be constituted by a switch for short-circuiting the output terminal of the power supply device and the ground, and the output terminal may be simply connected to the ground by a signal from the overcurrent detecting means. In this case, the output terminal and the ground may be short-circuited via a predetermined resistor as long as the power supply can flow a current of a predetermined value or more that can detect an overcurrent or a ground.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on an embodiment of the present invention with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a power supply circuit according to the present embodiment. The power supply circuit is provided between a power supply device 11 having an overcurrent (or short-circuit) protection function and an output terminal of the power supply device 11 and ground, and short-circuits the output terminal and ground in response to an overcurrent detection signal. A plurality of short circuits 12, a plurality of load circuits 15 respectively connected to branch lines 14 from a power supply line 13 extending from an output end of the power supply device 11, and a plurality of load circuits 15 respectively inserted into branch lines 14 corresponding to each load circuit 15. And an overcurrent detection section 16.

Each overcurrent detector 16 constantly monitors the load current of the corresponding load circuit 15, and its output is connected to a control terminal of the short circuit 12 via a control signal line 17. The overcurrent detection unit 16 generates an overcurrent detection signal 18 when detecting that the current flowing through the load circuit 15 has increased to a set current value or more. Overcurrent detection signal 1
8 is sent to the short circuit 12 to activate a switch in the short circuit 12 to turn it on. As a result, the output terminal of the power supply device 11 and the ground are forcibly short-circuited via the predetermined resistance value. As a switch of the short circuit 12,
An on / off switch such as a normal power transistor can be used.

Due to a short circuit between the output terminal of the power supply 11 and the ground, a large overcurrent of a predetermined current value or more flows from the power supply 11. The short power supply device 11 has a built-in overcurrent sensor for detecting a short circuit. The overcurrent sensor detects overcurrent flowing from the output terminal, and shuts off the main switch to stop the power supplied to the output terminal. As a result, the power supply to each load circuit 15 is stopped all at once.

According to the above embodiment, even if the overcurrent caused by the failure of each load circuit 15 is small, the power supply device 1
Since the power supply from the power supply 1 is reliably shut off, no fault such as overheating or disconnection occurs in the load circuit in which the fault has occurred or the corresponding power supply line, and the load circuit in which the fault has occurred is stopped. Also, there is no secondary disaster caused by the operation of the load circuit.

Instead of the power supply device 11 with an overcurrent protection function in the above embodiment, a power supply device with a ground protection may be employed. In this case, the current generated by the short circuit 12 may be a small current equal to or greater than the ground current that can be detected by the ground sensor. Switches with an overcurrent protection function or a grounding protection function attached to an overcurrent sensor or a grounding sensor are mass-produced as commercial products, and can be suitably used as a simple main switch for the power supply device.

The power supply circuit of the above embodiment can be used as any power supply circuit. For example, it can be used as a power supply circuit of a personal computer or a power supply circuit of various control systems.

As described above, the present invention has been described based on the preferred embodiment. However, the power supply circuit of the present invention is not limited to the configuration of the above-described embodiment. Power supply circuit with various modifications and changes,
It is included in the scope of the present invention.

[0019]

As described above, according to the present invention, a small accident in each load circuit is detected by using a power supply device having an overcurrent protection function or a ground protection function for supplying power to a plurality of loads. Since the entire power supply is stopped, the power supply device, the power supply line, and the load circuit can be reliably protected from an overcurrent failure, and a secondary disaster such as a system malfunction can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power supply circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional power supply circuit.

[Explanation of symbols]

 Reference Signs List 11 power supply circuit with overcurrent protection function 12 short circuit 13 power supply line 14 branch line 15 load circuit 16 overcurrent detection unit 17 control signal line 18 overcurrent detection signal

Claims (2)

[Claims] A power supply circuit having an overcurrent protection function for stopping supply of current from the output terminal when an overcurrent of a predetermined value or more is detected at the output terminal; and a plurality of load circuits connected to the output terminal. A plurality of overcurrent detection means disposed between the output terminal and the load circuit corresponding to each load circuit; and the plurality of overcurrent detection means connected to an output terminal of the power supply circuit. And an overcurrent generating means for generating an overcurrent at or above the predetermined value at an output terminal when at least one of them detects an overcurrent. 2. A power supply device having a ground protection function for stopping supply of current from the output terminal when grounding at the output terminal is detected; a plurality of load circuits connected to the output terminal; A plurality of overcurrent detection means disposed between the load circuit and the load circuit, the plurality of overcurrent detection means being connected to an output terminal of the power supply device, and at least one of the plurality of overcurrent detection means being overcurrent And a ground generating means for generating a ground at the output terminal when the power supply circuit detects the signal.