JPS63234624A - Switch self-hold control circuit - Google Patents

Abstract

PURPOSE:To attain low power consumption by disconnecting the power supply to a switch self-hold control circuit when the power supply to the system is disconnected. CONSTITUTION:In stopping the power supply to the system, a switch 4 is depressed to throw a moving contact (c) to the position of normally opened contact. When the output Q of a flip-flop 5 goes to a high level, the output Q of the flip-flop 6 is inverted from a high to a low level in response to the leading and then a transistor(TR) 9 is turned off. As a result, a switching TR 3 is turned off and the power supply to the system is stopped. The power supplied to the flip-flops 5, 6 through a power line 13 is disconnected at the same time. Thus, the power saving is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low power consumption type switch self-holding control circuit.

(Prior art) In order to reduce power consumption in the system as much as possible,
Power is supplied and cut off by controlling the switch on and off, but at this time, if the switch does not have a lock function,
A self-holding control circuit for the switch is required.

Fig. 2 shows a conventional switch self-holding control circuit of this type, in which 1 is a terminal connected to the power supply, 2 is a power supply terminal connected to the system, 3 is a switching transistor, and 4 is a terminal connected to a power supply. The switch consists of a normally open contact a, a normally open contact S, and a grounded movable contact C, 5 and 6 are flip-flops, 7 is a diode, and 8 is a capacitor.

In such a configuration, when the movable contact C of the switch 4 is connected to the normally open contact, the flip-flop 5 is set and the output Q becomes high. When the output Q of the flip-flop 6 becomes low in response to the rise of the output Q, the switching transistor 3 is turned on and power is supplied to the system.

Therefore, even if the movable contact C of the switch 4 returns and the output Q becomes low, the output Q of the flip-flop 6 remains low, so that the power supply to the system is maintained. Then, if you want to stop powering the system,
When the switch 4 is pressed down again and the output Q of the flip-flop 5 becomes high, the output Q of the flip-flop 6 is inverted from low to high, so the switching transistor 3 is turned off and the power supply to the system is cut off.

This state is maintained until the switch 4 is pressed next time.

(Problem to be Solved by the Invention) However, as is clear from FIG. 2, the switch self-holding control circuit with the above configuration always has power to the self-holding control circuit itself even when no power is supplied to the system. This poses a problem in terms of power saving.

The present invention solves the above-mentioned problems of the prior art, and when the power supply to the system is cut off, the power supply to the switch self-holding control circuit is also cut off, thereby reducing power consumption. This is what I did.

(Means for Solving the Problems) The switch self-holding control circuit of the present invention includes a first switching transistor disposed between a power supply and a system, a normally closed contact, a normally closed contact, and a movable contact. a switch that turns on the first transistor when the normally closed contact and the movable contact are connected; a first flip-flop that is directly set or reset by switching the switch; a second flip-flop whose output is switched between high and low each time a predetermined signal is output; and a power line that supplies power to the first and second flip-flops only when the first transistor is on.

(Function) According to the above configuration, power is supplied to the first and second flip-flops only when the first transistor is turned on, that is, when there is no power supply to the system, the power is supplied to the switch self-holding control circuit. The power supply will also be cut off, resulting in power savings.

(Example) Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which the same reference numerals as in FIG. A capacitor, 13 is a power supply line for supplying power to the flip-flop 5.6, and R□ to R6 are resistors.

Next, the operation of this embodiment will be explained. When movable contact C of switch 4 is turned to the normally closed contact side, resistor R4 and diode 1
Current flows through 0, which turns on the switching transistor 3 and provides power to the system. At the same time, power is supplied to the flip-flops 5 and 6 via the power supply line 13, and the flip-flops 5 and 6 become operational. Therefore, the flip-flop 5 is set and the output Q becomes high, and when the output Q of the flip-flop 6 becomes high in response to the rise of the output Q, the transistor 9 is turned on. Afterwards, if transistor 9 is on, switching transistor 3
remains on. Even if the movable contact C of the switch 4 returns and the output Q of the flip-flop 5 becomes low, the output Q of the flip-flop 6 remains high, so the transistor 9 remains on. , power supply to the system will continue.

Next, when stopping the power supply to the system, the switch 4 is pressed again to connect the movable contact C to the normally closed contact side.

Therefore, when the output Q of the flip-flop 5 becomes high, the output Q of the flip-flop 6 is inverted from high to low in response to the rise of the output Q, and the transistor 9 is therefore turned off. As a result, the switching transistor 3 is turned off and power supply to the system is stopped. At the same time power line 13
The power that was being supplied to the flip-flops 5 and 6 via the circuit is also cut off.

When supplying power to the system, it is unknown what state the flip-flop 6 is in, so when the switch 4 is first pressed, the output Q of the flip-flop 6 is reset by the differential signal from the resistor R5 and capacitor 8. state.

(Effects of the Invention) As explained above, according to the present invention, when the power supply to the system is cut off, the power supply to the switch self-holding control circuit is also cut off, which has the advantage of saving power. be.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a circuit diagram of an embodiment of the present invention.
FIG. 2 is a circuit configuration diagram of a conventional example. 2... Power supply terminal, 3... Switching transistor, 4... Switch, 5, 6...
・Flip-flop, 9...transistor, 13...power line. Patent applicant Tohoku Ricoh Co., Ltd.-7=

Claims (1)

[Claims] The first switch for switching placed between the power supply and the system.
a transistor, a switch that has a normally closed contact, a normally open contact, and a movable contact and turns on the first transistor when the normally open contact and the movable contact are connected; and a switch that directly sets or resets by switching the switch. a first flip-flop whose output is switched between high and low every time the first flip-flop outputs a predetermined signal; Alternatively, it may include a second transistor that is turned off and controls on/off of the first transistor, and a power line that supplies power to the first and second flip-flops only when the first transistor is turned on. Features a switch self-holding control circuit.