Touch control switch circuit

• US 4,731,548 A
• Filed: 09/29/1986
• Issued: 03/15/1988
• Est. Priority Date: 09/29/1986
• Status: Expired due to Term

• Current Assignee: Narton Corporation
• Original Assignee: Nartron Corporation
• Inventors: Ingraham, Ronald D.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Logan, Sharon D.
• Application Number:
  US06/913,084
• Time in Patent Office: 533 Days
• Field of Search: 307/116, 307/125, 307/252, 307/308, 315/34, 315/74, 315/208, 315/246, 315/362, 318/345, 318/446, 323/19, 323/24, 328/5, 200/DIG. 1
• US Class Current: 307/116
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

A touch controlled electronic switching circuit in which the body capacitance of the person actuating the device is coupled in series with current limiting resistors and a capacitor with the junction coupled to a logic circuit which responds thereto to provide a direct current control signal. The logic circuit has an output coupled to the gate terminal of a Triac coupled to a load for selectively applying current to said load during both half-cycles of each cycle of the line voltage supplied to the Triac and load.

Claims

1. A touch controlled electric switching circuit comprising:

a source of power for the actuation of a load to be selectively coupled to said source of power;

a controllable means for selectively coupling said source to a load; and

a control circuit including a series voltage divider input circuit including at least one capacitor having a first terminal connected to said source of power and an input touch terminal for coupling a person'"'"'s body capacitance in series with said at least one capacitor such that the voltage across said one capacitor produced by said source of power is changed when said input touch terminal is touched and said control circuit provides a control output signal in response to the touching of said touch terminal which signal is applied to said controllable means for selectively coupling said source of power to said load.

2. The circuit as defined in claim 1 wherein said source of power is an alternating current source and wherein said controllable means comprises a first solid-state switch.

3. The circuit as defined in claim 2 wherein said input circuit is coupled to said source of power and includes resistance means coupled in series between said touch terminal and said at least one capacitor.

4. The circuit as defined in claim 3 wherein said resistance means comprises a pair of serially coupled resistors each having a resistance of at least 1 megaohm.

5. A touch controlled electric switching circuit comprising:

a source of power for the actuation of a load to be selectively coupled to said source of power;

a controllable means for selectively coupling said source to a load; and

a control circuit including a series voltage divider input circuit including at least one capacitor and an input touch terminal for coupling a person'"'"'s body capacitance in series with said at least one capacitor such that the voltage between said one capacitor and said touch terminal is reduced when touched and said control circuit provides a control output signal in response to the touching of said touch terminal which signal is applied to said controllable means for selectively coupling said source of power to said load, wherein said source of power is an alternating current source and wherein said controllable means comprises a first solid-state switch, wherein said input circuit is coupled to said source of power and includes resistance means coupled in series between said touch terminal and said at least one capacitor, wherein said resistance means comprises a pair of serially coupled resistors each having a resistance of at least 1 megaohm and, wherein the junction of said at least one capacitor and said resistance means is coupled to a control terminal of a second solid-state switch coupled to said power source and responsive to the change in capacitance and resulting voltage change at said junction to provide a controlling signal.

6. The circuit as defined in claim 5 wherein said control circuit further includes a logic circuit having an input terminal coupled to said second solid-state switch and output terminal coupled to said first solid-state switch, said logic circuit latching in response to successive controlling signals for providing said control output signal.

7. The circuit as defined in claim 6 wherein said logic circuit comprises a squaring circuit serially coupled to a D-flip/flop circuit.

8. A touch controlled electric switching circuit comprising:

a source of alternating current power for the actuation of a load to be selectively coupled to said source;

a first solid-state switch for selectively coupling a load to said source and having a control input terminal for receiving control signals; and

a control circuit including a touch plate responsive to the touch of an individual to provide a direct current control output signal applied to said control input terminal such that said first switch is rendered conductive during each half-cycle of each cycle of applied alternating current voltage, wherein said control circuit includes a series voltage divider input circuit including said touch plate and at least one capacitor having a terminal remote from said touch plate connected to said source of alternating current power for coupling a person'"'"'s body capacitance in series with said at least one capacitor and said source of alternating current power such that said control circuit responds to the change in voltage across said one capacitor to selectively provide said direct current control signal.

9. The circuit as defined in claim 8 wherein said input circuit is coupled to said source of power and includes resistance means coupled in series between said touch plate and said at least one capacitor.

10. The circuit as defined in claim 9 wherein said resistance means comprises a pair of serially coupled resistors each having a resistance of at least 1 megohm.

11. A touch controlled electronic switching circuit comprising:

a source of alternating current power for the actuation of a load to be selectively coupled to said source;

a first solid-state switch for selectively coupling a load to said source and having a control input terminal for receiving control signals; and

a control circuit including a touch plate responsive to the touch of an individual to provide a direct current control output signal applied to said control input terminal such that said first switch is rendered conductive during each half-cycle of each cycle of applied alternating current voltage, wherein said control circuit includes a series voltage divider input circuit including at least one capacitor and said touch plate is coupled to said at least one capacitor for coupling a person'"'"'s body capacitance in series with said at least one capacitor such that said control circuit selectively provides said direct current control signal, said source of power and includes resistance means coupled in series between said touch plate and said at least one capacitor, wherein said resistance means comprises a pair of serially coupled resistors each having a resistance of at least 1 megaohm and, wherein the junction of said at least one capacitor and said resistance means is coupled to a control terminal of a second solid-state switch coupled to said power source and responsive to the change in capacitance and resulting voltage change at said junction to provide a controlling signal.

12. The circuit as defined in claim 11 wherein said control circuit further includes a logic circuit having an input terminal coupled to said second solid-state switch and ouput terminal coupled to said first solid-state switch, said logic circuit latching in response to successive controlling signals for providing said control output signal.

13. The circuit as defined in claim 12 wherein said logic circuit comprises a squaring circuit serially coupled to a D-flip/flop circuit.

14. A touch controlled electrical switching circuit for controlling power applied to a load, said circuit comprising:

a solid-state switch and means for coupling said switch between a load to be controlled and a supply of electrical power, said switch having a control input terminal; and

a control circuit including an input circuit and a logic circuit for receiving tactile command information from an operator and for providing a control output signal applied to said control input terminal of said solid-state switch, wherein said input circuit includes a touch terminal coupled to at least one capacitor having a terminal remote from said touch terminal coupled to the supply of power to define a voltage divider circuit with a person'"'"'s body capacitance, said input circuit further including resistance means coupled in series with said touch terminal and said capacitor for limiting current to said touch terminal and voltage level responsive means responsive to said voltage divider circuit for causing said logic circuit to change the state of said control output signal.

15. A touch controlled electrical switching circuit for controlling power applied to a load, said circuit comprising:

17. The circuit as defined in claim 15 wherein said control circuit further includes a logic circuit including a latching circuit having an output terminal coupled to said control input terminal of said first named solid-state switch.

19. The circuit as defined in claim 17 wherein said logic circuit includes a squaring circuit coupled to said latching circuit and said latching circuit comprises a D-flip/flop circuit.

16. a solid-state switch and means for coupling said switch between a load to be controlled and a supply of electrical power, said switch having a control input terminal;

and

a control circuit including an input circuit and a logic circuit for receiving tactile command information from an operator and for providing a control output signal applied to said control input terminal of said solid-state switch, wherein said input circuit includes a touch terminal coupled to at least one capacitor having a terminal remote from said touch terminal coupled to the supply of power to define a voltage divider circuit, said input circuit further including resistance means coupled in series with said touch terminal and said capacitor for limiting current to said touch terminal, wherein said input circuit further includes a second solid-state switch having a control input terminal coupled to said touch terminal and to the supply of operating power and responsive to the touching of said touch terminal for changing state.

18. The circuit as defined in claim 16 wherein said resistance means comprises a pair of serially coupled resistors each having a resistance of at least 1 megohm.

20. The electrical circuit as defined in claim 18 wherein said first named solid-state switch comprises a Triac.