JPS597773Y2 - switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit having a push button switch that indirectly turns on and off a circuit between a DC power source and a load, and particularly to a switching device that does not cause chattering and has a small leakage current.

Conventional switches often occupy a relatively large space like slide switches, or they have many problems that cause failures, such as high current being passed through the switch itself, and even if the switch does not extinguish the arc, it is subject to severe wear due to erosion, etc. There was a desire for a small, functional switch that could be turned on and off indirectly with a light touch.

In addition, although there have conventionally been switches that are turned on and off mechanically using push buttons, there have been no switches that are electrically operated indirectly by operating a push button.

Although it is possible to design a switch circuit using C-Mo5■C for such an indirect operation switch, C-Mo
It is not long enough to require 5 ICs, but it tends to be complicated, requiring the addition of transistors for current or voltage amplification, and it was hoped that it would be possible to create a simpler and more sophisticated circuit design using only transistors. .

Accordingly, an object of the present invention is to provide a switching device which does not cause chattering and generates little nok current by cleverly combining transistors and a small number of components to indirectly turn on and off with a soft one-touch switch.

Other objects and features of the present invention will become apparent from the following description and accompanying drawings.

An embodiment of the present invention will be described below according to the drawings.

The power supply forms a loop that passes through the emitter and collector of the transistor Tr1 and then through the load.

There is a circuit connecting the capacitor C1C2 and the power supply on the power supply side of the transistor Tr1, and the middle of C1C2 is connected to the switch SW.

The base of Tr1 is connected to a power supply via a resistor R1, the collector and emitter of a transistor Tr2.

Also, in parallel with the load, there is a circuit connecting the collector of Tr1, the resistor R3, the base of Tr2, the resistor R4, and the power supply.

The collector of Tr1 is connected to Tr2 via resistor R2 and capacitor Q.
The switch S reaches the base of R2 and C3.
W is connected.

As an example of this component, the capacitors C1C2C3 should preferably be tantalum with the same capacity, for example, 0.1 to 0.3 micro F, from the viewpoint of production control.

It is suitable that the resistors R1R2 and R3R4 have an IOK ohm and a resistance of about 50K ohm.

The switch SW is preferably a small, soft-touch manually operated push button with an automatic return contact.

Although not shown, this switch is turned on with the first push and then turned off with the second push, so it is advisable to add a pilot lamp to display the on/off state.

In such a structure, when the DC power source, the switching device of the present invention, and the load are connected, the capacitor C1C2 is charged together.

Since the transistor Tr is in an off state, the load does not operate.

When pushbutton switch SW is pressed now, the charge in capacitor C2 passes through this switch SW and passes through C3 to the NPN type Tr.
The base of Tr2 is reached and turned on, and the PNP type Tr is also turned on at the same time, and the application to the base of Tr2 continues through the circuit, so the switch device remains in the on state.
It is applied to the load from the power supply through Tr1 and continues to operate.

That is, even if the direct push button switch SW is turned off, the indirect switch Tr1 is operated and held, and the power is applied to the load from the power source to continue operation.

When the circuit is on, capacitor C3 is approximately (supply -V
be).

At this time, comparing the charging state of each capacitor, C1 and 02
Since they have the same capacitance and are connected in series, C2 has approximately 1/2 the voltage of C3.

Now, when the push button switch SW is pressed for the second time to turn off the entire switch device, the charge of C3 passes through C2 and reaches the transistor Tr2, and a reverse voltage is applied between the be of Tr2, turning Tr2 off, and at the same time Since Tr1 is also turned off, the switching device is turned off, and no charge is supplied to the load, so that the switching device stops.

As described above, since the switch device of the present invention indirectly turns on and off using a push button switch, almost no current flows through the switch, which has the following advantages.

1 No chattering.

2. Since the operating current is not turned on and off directly, the push button switch can be small, lightweight, and soft-touch, and the touch is light.

3. Since almost no current flows through the switch contacts, the contacts will not wear out and break down, reducing the chance of failure.

4 Leakage current is very small, a few nanoamperes.

This device not only has the above-mentioned advantages, but also has the advantage that it is a circuit suitable for desk IJ-} ICs because it is a low-cost and easy-to-manufacture circuit because it skillfully combines a small number of parts.

[Brief explanation of drawings]

The figure is an explanatory circuit diagram showing one embodiment of the present invention.

Claims (1)

[Scope of utility model registration request] It has a loop circuit that sequentially connects the positive pole of the power supply, the emitter and collector of the transistor Tr1, the load, and the negative pole of the power supply, and a series circuit that connects the positive pole of the power supply, the capacitors C1 and C2, and the negative pole of the power supply, and A series circuit connecting the base, the resistor R1, the collector and emitter of the transistor Tr2, and the negative pole of the power supply, and the transistor Tr1
It has a series circuit in parallel that connects the collector of the resistor R3, the base of the transistor Tr2, the resistor R4, and the negative pole of the power supply, and the intermediate between the capacitors C1 and C2, the collector of the transistor Tr1, and the base of the transistor Tr2. Switch SW
A switching device characterized by a structure having a circuit connected at.