JPS623857Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a multi-interlocking push switch, that is, when one switch out of multiple switches is pressed, this switch is locked, and when another switch is pressed in this state, it is locked previously. This invention relates to countermeasures against misuse and erroneous operation of a switch configured so that the switch returns to its original state and only the pressed switch is locked.

Conventionally, in multi-interlocking push switches, for example, if you forcefully press two or more switches, both of them may become locked, and if you press the switch halfway when changing the switch, the switch that is to be changed may also be locked before. It is well known that all the switches that have been locked may become unlocked.

The present invention provides an inexpensive circuit that generates a signal under such conditions to prevent malfunctions. An embodiment of the present invention will be described below with reference to the drawings. In the figure, S _A , S _B , and S _C indicate switches forming a multi-interlock switch. Switch S
A voltage V ₁ is supplied to the common terminal of _A , _SB , and _SC , and when any switch is turned on (only S _A is turned on in the figure), voltage V ₁ is output to the output terminal. Output terminals a of switches S _A , S _B , S _C ,
Reverse current prevention diodes D _A , D _B , D _C are connected in series with resistors R _A , R _B , R C to b and _c , and the cathodes of the diodes D _A to D _C are connected to form a common resistance. Grounded through _R1 . Therefore, for example, when any one of the switches S _A , S _B , and S _C is pressed, the resistance _R
B , or the value E ₁ obtained by dividing V ₁ by resistor R _C and common resistor R ₁ is output, and when any two switches are pressed, V ₁ is divided by resistor R _A , R _B , or R _C A value E 2 divided by the parallel resistance value of the two resistors and the common resistance R ₁ is output, and when three switches are pressed at the same time _, V ₁ is shared with the parallel resistance value of the resistors R _A , R _B , and R _C. The value _E3 divided by the resistor _R1 is output. Needless to say, E ₁ < E ₂ < E ₃ . _{Connect the point ​ ​}
By applying a voltage-divided value E _S and setting this E _S so that the transistor T ₁ is turned on when the base potential of the transistor T ₁ is greater than E ₁ , the switch S _A ~
When two or more of S _C are pressed, that is, when the base potential of transistor T ₁ reaches E ₂ or E ₃ , transistor T ₁ is turned on, and the collector potential of transistor T ₁ is lowered to ₃
A low level signal (hereinafter referred to as an "L" signal) is output from the Y point on the collector side of the circuit. Note that R ₄ is the collector resistance of transistor T ₁ , and R ₅ is the transistor
Base current limiting resistor of T ₃ , R ₆ is transistor T ₃
is the collector resistance of Further, the common cathode of D _A , D _B , and D _C is supplied to the base of the transistor T ₄ via the resistor R ₇ , and the collector output of the transistor T ₄ is connected to the base of the transistor T ₃ via the resistor R ₈ . Depending on the case, switches S _A , S _B , S
When all of the switches _C are off, that is, when no switch is pressed, the transistor _T4 is off and the transistor _T3 is on, and an L signal is also output from the Y point. Note that ^R9 is the collector resistance of transistor _T4 . For example, in the case of a radio receiver, the above-mentioned L signal can be used to prevent malfunction of the set due to incorrect use or operation of the multi-linked push switch by preventing the detection output of FM, AM, etc. from being supplied to the low frequency amplification stage, or by turning on a warning lamp. It can be prevented.

Note _that capacitor _C1 outputs an L signal to point Y when all switches S _A to S _C are temporarily turned off during switching between _them , or when two or more switches are turned on. resistance to prevent
It constitutes a filter in combination with R ₁ and R ₈ . Furthermore, in the case of a multi-interlock switch in which two or more buttons are not pressed, the transistors T ₁ and T ₂ and the resistors R ₂ , R ₃ , R ₄ and R ₅ are not required. In other words, it is sufficient to consider only the state in which all switch buttons are not pressed.

As explained above, according to the switch circuit of the present invention, a simple and inexpensive countermeasure circuit can be obtained against misuse and erroneous operation of a multi-interlock switch.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing a switch circuit in an embodiment of the present invention. S _A , S _B , S _C ... Switches constituting a multi-interlock push switch, R _A , R _B , R _C ... Resistance, R ₁
……Common resistance, V ₁ ……Power supply voltage.

Claims (1)

[Scope of utility model registration request] A multi-interlock push switch has a voltage applied to a common terminal, a series circuit of a resistor and a reverse current prevention diode is inserted into each of the plurality of switch output terminals, and a resistor is connected to a common connection point between the cathodes of the diodes of each of the plurality of series circuits. a first transistor whose base is connected through the transistor and whose emitter is grounded; and a second transistor whose base is connected to the collector of the first transistor and which has a capacitor connected to the ground through a resistor and whose emitter is grounded. a divided resistor provided between the cathode common connection point of the diode and the ground, a third transistor whose base is connected to the connection point between the divided resistor and the cathode common connection point; a fourth transistor whose base is resisted by the collector of the transistor, and whose collector is connected to the base of the second transistor; A switch circuit characterized in that when two or more switches are pressed, the switch circuit is turned on by increasing the base potential due to the divided resistors.