JPH0749546Y2 - Power supply circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a power supply circuit with an automatic cutoff function, which has a control circuit for cutting off the output when an overvoltage or the like is detected. The present invention relates to a power supply circuit with an automatic cutoff function that enables connection of the

[Prior Art] A conventional power supply circuit with an automatic shutoff function, when the power supply to the control circuit section is performed from the AC line,
When the output is cut off and held in the off state, the AC input is set to 1
If it had to be turned off and then turned on again, the control circuit could not be reset and the output cutoff state could not be restored.

By the way, in a device provided with such a power supply circuit, for example, a personal computer, it is necessary to connect an external device attached to the device, for example, a floppy disk driver. At that time, it is usual to use a single switch shared by both devices for starting and stopping (on / off) the devices. This is because it is not preferable for general users to operate two operations on and off, rather than save one switch. This is because, especially in the case of suspension, it is often possible to forget to turn off one of them, which reduces the commercial value of the personal computer even if it does not cause a fatal danger.

[Problems to be Solved by the Invention] However, a problem arises when two switches are turned on and off by one switch as described above.

FIG. 2 is a diagram showing the configuration of a conventional power supply circuit of this type. The main power supply circuit of this personal computer is composed of a rectifying / smoothing unit 3, a power conversion unit 4, an output detection unit 6, and a control circuit unit 7. The power is input from the inlet 1 to
The C input switch 15 turns the power on and off. And the first
Power to the load 5 via the output terminal 2a of the
A part of the input power is also supplied through the outlet 2 to the floppy disk driver 16 which is an external circuit indirectly related to this power supply circuit via the output terminal 2b of the.

In this device, when the output detection unit 6 detects an abnormal voltage, it is transmitted to the controller circuit 7 via the photocoupler 10, and the controller circuit unit controls the power conversion unit 4 to cut off the power supply output.

In the device of FIG. 2, it is necessary to turn off the AC input switch once in order to reset the control circuit unit and recover from the output cutoff state. Therefore, the power supply of the floppy disk driver 16 is turned off during that time, and the floppy disk stops and normal operation cannot be performed. In some cases, it may be necessary to re-execute the operation for a considerable time before that point, which may cause an extremely unfavorable state.

In addition, depending on the structure of the power supply of the floppy disk driver, the electricity stored in the large-capacity capacitor of the power supply flows backward in the power supply unit immediately after being cut off, and the output cutoff works at a low voltage and the main power supply circuit cannot be turned on ( It may occur for a few seconds).

Therefore, the present invention seeks to obtain a power supply circuit that can restore the output cutoff state in the control circuit without switching off the AC input.

[Means for Solving the Problems] According to the present invention, the detection signal of the output detection unit indicates an abnormality using the DC output of the rectification smoothing unit, the power conversion unit, the output detection unit, and the rectification smoothing unit as a power source. A main power supply which has a control circuit part for controlling the power conversion part to shut off the generation of the main power supply output, and which receives the power supply power from the outside through the switch means and inputs it to the rectifying and smoothing part. In a power supply mechanism, which is a circuit unit and is configured to be attachable to an external device that operates by extracting power source power from the latter stage of the switch means, an electromotive switch, a relay for controlling on / off of the switch means, a latch circuit , And an auxiliary power supply unit having means for issuing a cutoff signal when the electromotive switch is operated, and a direct power supply for the control circuit unit when the cutoff signal is received. When the power output is cut off after the power is turned on, the control circuit section is reset and the main power output is reissued. A power supply circuit having the above structure is obtained.

[Embodiment] FIG. 1 shows an embodiment of the present invention, and the same components as those in FIG. 2 are designated by the same reference numerals.

In this configuration, in addition to the main power supply circuit including the rectifying / smoothing unit 3, the power conversion unit 4, the output detection unit 6, and the control circuit unit 7,
An auxiliary power supply unit 9 including a relay 13 and a relay contact 13-1 and an electromotive switch 8 for driving the auxiliary power supply unit are provided.

When an abnormal voltage such as an overvoltage is detected in the output detector 6 while the power is on, the output cutoff circuit in the control circuit 7 operates and the output is turned off. Remains on because the latch circuit 14 is working. By turning on the electromotive switch 8, the photo diode 12-1 is linked to the latch circuit 14 in the auxiliary power source section to turn off the light which is the cutoff signal. A phototransistor 12-which emits a signal and receives the optical signal on a line which supplies DC power to the control circuit 7.
2 can be operated to cut off the power supply, and an output cutoff circuit (not shown) in the control circuit 7 can be reset to restore the output.

In addition, a mechanism for turning off the entire apparatus, that is, the relay circuit 13 is actuated on the auxiliary electrode portion 9 so that the relay contact 13-
A circuit including a photocoupler that disconnects 1 is required,
It is omitted because it is irrelevant to the characteristic part of the present invention, and if this is written in FIG. 1, the characteristic structure of the auxiliary electrode part 9 becomes difficult to see.

[Effect of the Invention] The power supply circuit of the present invention is provided with the auxiliary power supply, the electromotive switch, the means for cutting off the power supply of the control circuit, and the like as described above. With the same number of switches, the output cutoff circuit in the control circuit can be reset and the output restored without turning off the AC input once, and thus without turning off the power supply to the external device, and the power is turned off. If this happens, the influence from external devices that may occur will disappear in the control circuit, and the time during which the power cannot be turned on will be eliminated.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional example. Explanation of symbols: 1 is inlet, 2 is outlet, 3 is rectifying / smoothing part, 4 is power conversion part, 5 is load, 6 is output detection part, 7 is control circuit part, 8 is electromotive switch, 9 is auxiliary power supply Part, 10 is a photocoupler, 11 is a photocoupler, 12-1 is a photodiode, 12
-2 is a photocoupler, 13 is a relay, 13-1 is a relay contact, 14
Is a latch circuit, 15 is an AC input switch, and 16 is a floppy disk driver (external circuit).

Claims (1)

[Scope of utility model registration request] 1. A rectifying / smoothing section, a power converting section, an output detecting section, and a DC output of the rectifying / smoothing section as a power source for controlling the power converting section when a detection signal of the output detecting section indicates an abnormality. A main power supply circuit unit that has a control circuit unit that shuts off the generation of the main power supply output, and that takes in the power supply power from the outside through the switch unit and inputs it to the rectifying and smoothing unit. In a power supply mechanism configured to be attachable to an external device that operates by extracting power from the latter stage, when an electromotive switch, a relay for controlling on / off of the switch means, a latch circuit, and the electromotive switch are operated An auxiliary power supply unit having means for issuing a cutoff signal,
Means for disconnecting DC power, which is the power source of the control circuit unit when receiving the cutoff signal, and when the electromotive switch is operated when the power supply output is interrupted after the power is turned on, A power supply circuit characterized in that the control circuit section is reset and the main power supply output is emitted again.