JPH04308422A - Power supply cut-off control system - Google Patents

Abstract

PURPOSE:To output a DC voltage output cutting-off signal to a power source the DC output voltage of which is to be quickly dropped by promptly detecting a drop in an AC input voltage. CONSTITUTION:AC input voltages are supplied to the first and second power sources 1 and 2 and an AC input voltage detection circuit 3. A DC output voltage 6 and DC voltage turning on signal 4 are outputted from the power source 1. The voltage 6 is supplied to a logic circuit, etc. The second power source 2 supplies a DC output voltage 7 to a motor, etc., in response to the signal 4 and stops the supply of the voltage 7 in response to a DC voltage output discontinuing signal 5. The signal 5 is generated by the circuit 3 when the circuit 3 detects a drop in an AC input voltage. Therefore, the DC output voltage 8 of the second power source 2 can be dropped earlier than the DC output voltage 6 of the first power source 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power on/off control system for controlling alternating current voltage.

0002

2. Description of the Related Art A conventional system of this type will be explained with reference to FIG.

Referring to FIG. 2, in the conventional system,
AC input voltage is applied to third and fourth power supplies 8 and 9. In response to this DC input, the third power supply 8 outputs a DC output voltage 11 and a DC voltage input signal 10. The DC voltage input signal 10 is used as a signal for outputting the DC voltage of the fourth power supply 9. This DC voltage input signal 1
0, the fourth power supply 9 generates a DC output voltage 12.

[0004] When the AC input voltage is cut off, the fall sequence of the third and fourth power supplies 8 and 9 is not determined depending on the instantaneous interruption withstand time and load capacity of the third and fourth power supplies 8 and 9. For this reason, there is a problem when the power supply for a logic circuit is shut off after the power supply for a motor is shut off to protect data, such as the power supply used for a disk.

[0005]

OBJECTS OF THE INVENTION It is an object of the present invention to provide a power on/off control system that protects data by stopping power to a motor and then stopping power to a logic circuit.

[0006]

[Structure of the Invention] The system of the present invention includes a first power supply that inputs an AC voltage and outputs a DC output, and a second power supply that starts an output in response to a turn-on signal that is the DC output of the first power supply. and a power supply, wherein the detection signal of the alternating current voltage cutoff is used as a cutoff signal, and the cutoff signal is sent to the second power supply immediately after a required momentary cutoff tolerance time of the second power supply has elapsed when the alternating current voltage is momentarily cut off. The AC input voltage detection circuit is characterized in that it includes an AC input voltage detection circuit that outputs an AC input voltage.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention includes:
It includes a first power supply 1 that inputs an AC voltage, a second power supply 2, and an AC input voltage detection circuit 3. In response to the input of AC voltage, the first power supply 1 generates a DC output voltage 6 for supplying to a logic circuit, etc., and a DC voltage turn-on signal 7 for sending out a DC output voltage 7 from the second power supply 2. Occur.

The AC input voltage detection circuit 3 detects drooping of the AC input voltage and generates a DC voltage output cutoff signal 5. The second power source 2 is used as a power source for the motor. This second power supply 2 receives a DC voltage input signal 4 from the first power supply 1.
In response to this, a DC output voltage 7 is generated to be applied to a motor or the like, and generation of the DC output voltage 7 is stopped by a DC voltage output cutoff signal 5 from the AC input voltage detection circuit 3.

Despite the interruption of the AC input voltage, the first
The power supply 1 and the second power supply 2 have their own momentary interruption tolerance. However, the AC input voltage detection circuit 3 detects a drop in the AC input voltage and sends the DC voltage output cutoff signal 5 to the second power supply 2, thereby changing the DC output voltage 7 of the second power supply 2 to the first power supply. DC output voltage 6 of 1.

[0011]

Effects of the Invention The present invention has a first power source and a second power source that input AC voltage and output AC voltage, and uses the output voltage of the first power source as a turn-on signal for the second power source. The present invention is directed to a power supply system having a sequence in which the output of the second power supply is turned on by this input signal. In such a system, when the AC voltage is cut off, a signal detected by the AC voltage instantaneous interruption detection circuit 3 is given to the second power supply 2 as a cutoff signal. This disconnection signal is transmitted immediately after the instantaneous interruption tolerance time required for the second power source has elapsed after the instantaneous interruption of the AC power source. The first power supply has an instantaneous interruption tolerance time longer than a certain period of time with respect to the second power supply.

[0012] By having such characteristics, the present invention stops the activity of the second power supply for the motor in order to protect data, such as the power supply used for the disk, and then
This has the effect of stopping the activity of the first power supply for the logic circuit and preventing erroneous changes in data.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a conventional control system.

[Explanation of symbols]

1 First power supply 2 Second power supply 3 AC input 4 DC voltage output signal 5 DC voltage output cutoff signal 6 DC output voltage 7 DC output voltage 8 Third power supply 9 Fourth power supply 10 DC voltage output signal 11 DC output voltage 12 DC output voltage

Claims (1)

[Claims] [Claim 1] A system comprising a first power supply that inputs an AC voltage and outputs a DC output, and a second power supply that starts up its output in response to a turn-on signal that is the DC output of the first power supply. an AC input voltage that uses the AC voltage cutoff detection signal as a disconnection signal and outputs the disconnection signal to the second power source immediately after a necessary instantaneous interruption withstand time of the second power source has elapsed in the event of a momentary AC voltage interruption; A power on/off control system comprising a detection circuit.