Touch switch with integral control circuit

• US 7,218,498 B2
• Filed: 10/15/2002
• Issued: 05/15/2007
• Est. Priority Date: 01/19/1999
• Status: Expired due to Term

• Current Assignee: Touchsensor Technologies LLC (Methode Electronics Incorporated)
• Original Assignee: Touchsensor Technologies LLC (Methode Electronics Incorporated)
• Inventors: Caldwell, David W.
• Primary Examiner(s): Sircus; Brain
• Assistant Examiner(s): Nguyen; Danny
• Application Number:
  US10/272,377
• Publication Number:
  US 20030122432A1
• Time in Patent Office: 1,673 Days
• Field of Search: 361/179, 361/181, 361/280, 361/1, 361/5, 361/6, 361/7, 307/99, 307/112, 307/125, 307/116, 307/127
• US Class Current: 361/179
• CPC Class Codes: A47B 57/00 Cabinets, racks or shelf units, characterised by features for adjusting shelves or partitions shelf units with stackable uprights A47B87/00; details of cabinets, racks or shelf units in general A47B96/00; brackets adjustable in themselves A47B96/07
• CPC Class Codes: A47B 96/025 Shelves with moving elements, e.g. movable extensions or link elements cabinets, racks or shelf units enabling enlargement in height, length or depth A47B45/00
• CPC Class Codes: A47F 3/06 with movable or removable shelves or receptacles A47F3/0486 takes precedence; display racks with movable parts A47F5/0081
• CPC Class Codes: A47F 5/0043 Show shelves shelves in general A47B96/02; brackets or similar shelf-supporting means A47B96/06; advertising or price indication G09F
• CPC Class Codes: F25D 2325/022 Shelves made of glass or ceramic
• CPC Class Codes: F25D 2331/803 Bottles
• CPC Class Codes: F25D 25/02 by shelves
• CPC Class Codes: G09F 3/204 specially adapted to be attached to a shelf or the like
• CPC Class Codes: G09F 9/30 in which the desired character or characters are formed by combining individual elements panels comprising a number of electrodes in a single cell controlling light arriving from an independent light source, e.g. electro-optical or magneto-optical cell, G02F1/00
• CPC Class Codes: H03K 17/96 Touch switches specially adapted for electronic time-pieces with no moving parts G04G21/08

Abstract

A touch switch apparatus for detecting the presence of an object such as a human appendage, the apparatus having a touch pad, an electric field generated about the touch pad and also having a preferably integrated and local control circuit connected to the touch pad and to a controlled device. The touch switch apparatus also having at least one of an input circuit portion for providing input signals to a decision circuit, swamping capacitance, active blocking devices, peak detector circuits, and a dual connection output latch circuit portion.

Claims

1. An electronic sensor apparatus comprising:

a first electrode;

a second electrode;

a signal source; and

a control circuit,

said control circuit comprising;

an input section having a first input channel and a second input channel;

a decision section having a first input, a second input, and an output; and

an output section;

said first input channel coupled to said signal source, to said first electrode, and to said first input of said decision section, said first input channel comprising at least one first input channel electrical component;

said second input channel coupled to said signal source, to said second electrode, and to said second input of said decision section, said second input channel comprising at least one second input channel electrical component, each of said second input channel electrical components corresponding to one of said first input channel electrical components; and

said output of said decision section coupled to said output section;

wherein each of said second input channel electrical components is electrically matched to the corresponding first input channel electrical component.

2. The apparatus of claim 1 wherein a first of said first input channel electrical components comprises a first transistor having an input terminal, an output terminal, and a control terminal;

said input terminal of said first transistor coupled to said signal source and to said first electrode; and

said output terminal of said first transistor coupled to said first input of said decision section; and

wherein a first of said second input channel electrical components comprises a second transistor having an input terminal, an output terminal, and a control terminal;

said input terminal of said second transistor coupled to said signal source and to said second electrode; and

said output terminal of said second transistor coupled to said second input of said decision section.

3. The apparatus of claim 2 wherein said first input channel further comprises a first peak detector circuit.

4. The apparatus of claim 3 wherein said first peak detector circuit comprises a first rectifier coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said first rectifier and to said first input of said decision section.

5. The apparatus of claim 4 wherein said first rectifier comprises a first diode.

6. The apparatus of claim 3 wherein said first peak detector circuit comprises a third transistor coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said third transistor and to said first input of said decision section.

7. The apparatus of claim 3 wherein said second input channel further comprises a second peak detector circuit.

8. The apparatus of claim 7 wherein said first peak detector circuit comprises a first rectifier coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said first rectifier and to said first input of said decision section and said second peak detector circuit comprises a second rectifier coupled to said output terminal of said second transistor and to said second input of said decision section and a second capacitor coupled to said second rectifier and to said second input of said decision section.

9. The apparatus of claim 8 wherein at least one of said first rectifier and said second rectifier comprises a diode.

10. The apparatus of claim 7 wherein said first peak detector circuit comprises a third transistor coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said third transistor and to said first input of said decision section and said second peak detector circuit comprises a fourth transistor coupled to said output terminal of said second transistor and to said second input of said decision section and a second capacitor coupled to said fourth transistor and to said second input of said decision section.

11. The apparatus of claim 2 wherein said first input channel further comprises a first square root extractor.

12. The apparatus of claim 11 said second input channel further comprises a second square root extractor.

13. The apparatus of claim 1 wherein said output section comprises an output line.

14. The apparatus of claim 13 wherein said output line is coupled to a controlled device.

15. The apparatus of claim 1 wherein said output section comprises a drive transistor.

16. The apparatus of claim 15 wherein said drive transistor comprises an input terminal, an output terminal, and a control terminal, said output of said decision section coupled to said control terminal of said drive transistor.

17. The apparatus of claim 16 wherein said output terminal of said drive transistor is coupled to a controlled device.

18. The apparatus of claim 1 wherein said output section comprises a latch.

19. The apparatus oc claim 18 wherein said latch comprises a self-holding latch.

20. The apparatus of claim 19 wherein said latch is coupled to a controlled device.

21. The apparatus of claim 1 wherein said control circuit is embodied on an integrated circuit.

22. The apparatus of claim 21 wherein said integrated circuit is proximate at least one of said first electrode and said second electrode.

23. The apparatus of claim 1 wherein said signal source provides a periodic output signal.

24. The apparatus of claim 1 wherein said signal source comprises an oscillator.

25. The apparatus of claim 2 wherein at least one of said first transistor and said second transistor comprises an n channel metal oxide transistor.

26. The apparatus of claim 2 wherein at least one of said first transistor and said second transistor comprises a p channel metal oxide transistor.

27. The apparatus of claim 2 wherein at least one of said first transistor and said second transistor comprises an npn bipolar transistor.

28. The apparatus of claim 2 wherein at least one of said first transistor and said second transistor comprises a pnp bipolar transistor.

29. The apparatus of claim 1 further comprising a first resistor coupled to said signal source and said first electrode.

30. The apparatus of claim 29 further comprising a second resistor coupled to said signal source and said second electrode.

31. The apparatus of claim 2 further comprising a first resistor coupled to said signal source, said first electrode, and said first transistor.

32. The apparatus of claim 31 further comprising a second resistor coupled to said signal source, said second electrode, and said second transistor.

33. The apparatus of claim 1 wherein said signal source provides an electrical signal to at least one of said first electrode and said second electrode.

34. The apparatus of claim 1 wherein said second electrode is further coupled to a reference potential.

35. The apparatus of claim 34 wherein said reference potential is ground.

36. An electronic sensor apparatus comprising:

a first electrode;

a signal source; and

a control circuit,

said control circuit comprising;

an input section having a first input channel and a second input channel;

a decision section having a first input, a second input, and an output; and

an output section;

said first input channel coupled to said signal source, to said first electrode, and to said first input of said decision section, said first input channel comprising at least one first input channel electrical component;

said second input channel coupled to said signal source and to said second input of said decision section, said second input channel comprising at least one second input channel electrical component, each of said second input channel electrical components corresponding to one of said first input channel electrical components; and

said output of said decision section coupled to said output section;

wherein each of said second input channel electrical components is electrically matched to the corresponding first input channel electrical component.

37. The apparatus of claim 36 wherein a first of said first input channel electrical components comprises a first transistor having an input terminal, an output terminal, and a control terminal;

said input terminal of said first transistor coupled to said signal source and to said first electrode; and

said output terminal of said first transistor coupled to said first input of said decision section; and

wherein a first of said second input channel electrical components comprises a second transistor having an input terminal, an output terminal, and a control terminal;

said input terminal of said second transistor coupled to said signal source and said output terminal of said second transistor coupled to said second input of said decision section.

38. The apparatus of claim 37 wherein said first input channel further comprises a first peak detector circuit.

39. The apparatus of claim 38 wherein said first peak detector circuit comprises a first rectifier coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said first rectifier and to said first input of said decision section.

40. The apparatus of claim 39 wherein said first rectifier comprises a first diode.

41. The apparatus of claim 40 wherein said first peak detector circuit comprises a third transistor coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said third transistor and to said first input of said decision section.

42. The apparatus of claim 38 wherein said second input channel further comprises a second peak detector circuit.

43. The apparatus of claim 42 wherein said first peak detector circuit comprises a first rectifier coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said first rectifier and to said first input of said decision section and said second peak detector circuit comprises a second rectifier coupled to said output terminal of said second transistor and to said second input of said decision section and a second capacitor coupled to said second rectifier and to said second input of said decision section.

44. The apparatus of claim 43 wherein at least one of said first rectifier and said second rectifier comprises a diode.

45. The apparatus of claim 42 wherein said first peak detector circuit comprises a third transistor coupled to said output terminal of said first transistor and to said first input of said decision section and a first capacitor coupled to said third transistor and to said first input of said decision section and said second peak detector circuit comprises a fourth transistor coupled to said output terminal of said second transistor and to said second input of said decision section and a second capacitor coupled to said fourth transistor and to said second input of said decision section.

46. The apparatus of claim 37 wherein said first input channel further comprises a first square root extractor.

47. The apparatus of claim 46 wherein said second input channel further comprises a second square root extractor.

48. The apparatus of claim 36 wherein said output section comprises an output line.

49. The apparatus of claim 48 wherein said output line is coupled to a controlled device.

50. The apparatus of claim 36 wherein said output section comprises a drive transistor.

51. The apparatus of claim 50 wherein said drive transistor comprises an input terminal, an output terminal, and a control terminal, said output of said decision section coupled to said control terminal of said drive ransistor.

52. The apparatus of claim 51 wherein said output terminal of said drive transistor is coupled to a controlled device.

53. The apparatus of claim 36 wherein said output section comprises a latch.

54. The apparatus of claim 53 wherein said latch comprises a self-holding latch.

55. The apparatus of claim 54 wherein said latch is coupled to a controlled device.

56. The apparatus of claim 36 wherein said control circuit is embodied on an integrated circuit.

57. The apparatus of claim 56 wherein said integrated circuit is proximate said first electrode.

58. The apparatus of claim 36 wherein said signal source provides a periodic output signal.

59. The apparatus of claim 36 wherein said signal source comprises an oscillator.

60. The apparatus of claim 37 wherein at least one of said first transistor and said second transistors comprises an n channel metal oxide transistor.

61. The apparatus of claim 37 wherein at least one of said first transistor and said second transistors comprises a p channel metal oxide transistor.

62. The apparatus of claim 37 wherein at least one of said first transistor and said second transistors comprises an npn bipolar transistor.

63. The apparatus of claim 37 wherein at least one of said first transistor and said second transistors comprises a pnp bipolar transistor.

64. The apparatus of claim 36 further comprising a first resistor coupled to said signal source and said first electrode.

65. The apparatus of claim 37 further comprising a first resistor coupled to said signal source, said first electrode, and said first transistor.

66. The apparatus of claim 36 wherein said signal source provides an electrical signal to said first electrode.