Touch switch with integral control circuit

• US 6,713,897 B2
• Filed: 10/25/2001
• Issued: 03/30/2004
• 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, Brian
• Assistant Examiner(s): DEBERADINIS, ROBERT L
• Application Number:
  US10/027,884
• Publication Number:
  US 20020057020A1
• Time in Patent Office: 887 Days
• Field of Search: 307/652, 307/109, 307/125, 307/139, 341/33, 200/512
• US Class Current: 307/125
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/96077 comprising an electrode which is floating

Abstract

A touch switch apparatus for detecting the presence of an object such as a human appendage, the apparatus having a touch pad and a local control circuit connected to the touch pad and to a controlled device. The touch pad preferable includes a first electrode and a second electrode spaced from and surrounding the first electrode. The control circuit is preferably in integrated circuit form. A signal is provided to the touch pad to generate an electric field thereabout. Introduction of a stimulus near the touch pad disturbs the electric field. The control circuit detects the electric field disturbance in and generates a control signal in response.

Claims

1. An electrical switch apparatus responsive to human proximity and adapted to control a controlled device, comprising:

a touch pad;

an integrated circuit coupled to said touch pad, wherein said integrated circuit comprises a startup and bias section, a pulse generator and logic section, a decision section, and a self holding latch section; and

a control line coupled to said integrated circuit, said control line further coupled to said controlled device;

wherein the distance between said integrated circuit and said controlled device is substantially greater than the distance between said integrated circuit and said touch pad.

2. The apparatus of claim 1 further comprising at least a first active element coupled to said touch pad, said pulse generator and logic section, and said decision section.

3. The apparatus of claim 2 wherein said touch pad comprises at least a first electrode, said first active element coupled to said first electrode, said pulse generator and logic section, and said decision section.

4. The apparatus of claim 3 further comprising a second active element, said second active element coupled to said second electrode said pulse generator and logic section, and said decision section.

5. The apparatus of claim 4 wherein said touch pad further comprises a second electrode, said second active element coupled to said second electrode, said pulse generator and logic section, and said decision section.

6. The apparatus of claim 1 wherein said control line is coupled to said decision section.

7. The apparatus of claim 1 wherein said control line is coupled to said self holding latch section.

8. An electrical switch apparatus responsive to human proximity and adapted to control a controlled device, comprising:

a first electrode;

a second electrode;

an integrated circuit coupled to said first electrode and said second electrode, wherein said integrated circuit comprises a startup and bias section, a pulse generator and logic section, a decision section, and a self holding latch section; and

a control line coupled to said integrated circuit, said control line further coupled to said controlled device;

wherein the length of said control line is substantially greater than the distance between said integrated circuit and said touch pad.

9. The apparatus of claim 8 further comprising a first active element, said first active element coupled to said first electrode, said pulse generator and logic section, and said decision section.

10. The apparatus of claim 9 further comprising a second active element, said second active element coupled to said second electrode, said pulse generator and logic section, and said decision section.

11. The apparatus of claim 8 wherein said control line is coupled to said decision section.

12. The apparatus of claim 8 wherein said control line is coupled to said self holding latch section.