JPH0481893B2 - - Google Patents

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, the switch is controlled to turn on and off to supply and cut off power. At this time, if the switch does not have a lock function, the self-holding function of the switch A control circuit 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, and 3 is a self-holding control circuit for a switch.
4 is a switching transistor, 4 is a switch consisting of a normally open contact a, a normally open contact b, 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 b, the flip-flop 5 is set and the output Q becomes high. When the output 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. Next, if you want to stop power supply to the system, push down switch 4 again, and when the output Q of flip-flop 5 becomes high, the output of flip-flop 6 is reversed from low to high, so switching transistor 3 is turned off. , 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 configured as described above always has power supply to the self-holding control circuit itself even when no power is supplied to the system. This posed 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 being interrupted, the power supply to the switch self-holding control circuit is also cut off to reduce power consumption. This is what I did.

(Means for Solving the Problems) The switch self-holding control circuit of the present invention provides a switch self-holding control circuit for switching between a power supply and a system.
a transistor, a switch having a normally closed contact, a normally open contact, and a movable contact, which 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 that is
a second flip-flop whose output is switched between high and low every time the flip-flop outputs a predetermined signal; and a second flip-flop whose output is turned on or off depending on the output state of the second flip-flop to control 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 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 electrodes to the switch self-holding control circuit are The supply will also be cut off, resulting in power savings.

(Example) Hereinafter, an example 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. 13 is a power supply line for supplying power to flip-flops 5 and 6,
_R1 to _R5 are resistances.

Next, the operation of this embodiment will be explained. switch 4
When the movable contact c is moved to the normally open contact b side, the resistance R ₄ ,
Power flows through the diode 10, which turns on the switching transistor 3 and supplies power to the system. At the same time, power line 13
Power is supplied to flip-flops 5 and 6 through the circuit, and the flip-flops become operational. Therefore, the flip-flop 5 is set and the output Q becomes high, and in response to the rise of the output Q, the output Q of the flip-flop 6 is set.
When becomes high, transistor 9 turns on.
Thereafter, if transistor 9 is on, switching transistor 3 remains on. Here, even if the movable contact c of the switch 4 returns and the output Q of the flip-flop 5 becomes low, the flip-flop 6
Since the output Q remains high, transistor 9 remains on, and power continues to be supplied to the system.

Next, when stopping the power supply to the system, press the switch 4 again to connect the movable contact c to the normally open contact side. Then, in the same way as when starting power supply to the system, power flows through the resistor R ₄ and the diode 10, and the output Q of the flip-flop 5 becomes high, and in response to the rise of the output Q, the input of the flip-flop 6 becomes ( low) is called in, the output Q of flip-flop 6 is inverted from high to low, and transistor 9 is turned off. Even if transistor 9 is turned off, current flows through resistor R ₄ and diode 10 while switch 4 is pressed, so switching transistor 3 remains on. At this point, the movable contact c of the switch 4 returns to its original state, and current no longer flows through the resistor R ₄ and the diode 10. At the same time, even if the output Q of the flip-flop 5 becomes low, the output Q of the flip-flop 6 remains low. Therefore, transistor 9
As a result, the switching transistor 3 is turned off and the power supply to the system is cut off.

When supplying power to the system, it is unknown what state the flip-flop 6 is in, so when the first switch 4 is pressed, the resistor ₅
The output Q of the flip-flop 6 is reset by the differential signal from the capacitor 8.

(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. There is.

[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 configuration diagram of a conventional example. 2...Power supply terminal, 3...Switching transistor, 4...Switch, 5, 6...Flip-flop, 9...Transistor, 13...Power line.

Claims (1)

[Claims] 1. A first transistor for switching disposed between a power supply and a system, and a normally closed contact, a normally open contact, and a movable contact, and when the normally open contact and the movable contact are connected, the first transistor a first flip-flop that is directly set or reset by switching the switch; and a second flip-flop whose output is switched between high and low every time the first flip-flop outputs a predetermined signal. a second transistor that is turned on or off depending on the output state of the second flip-flop to control the on or off of the first transistor; A switch self-holding control circuit comprising: a power line that supplies power to a flip-flop;