Capacitive sensor device and method for operating a capacitive sensor device

• US 9,954,524 B2
• Filed: 01/12/2012
• Issued: 04/24/2018
• Est. Priority Date: 01/12/2011
• Status: Active Grant

• Current Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Original Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Inventors: Kaltner, Claus
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): Monsur, Nasima
• Application Number:
  US13/979,204
• Publication Number:
  US 20150288361A1
• Time in Patent Office: 2,294 Days
• Field of Search: 324671, 324662, 324686, 324629, 324658, 324660, 324679, 324690, 324600, 324548, 324672, 324 711, 345174, 345173, 345156, 345 55, 178 1806, 178 1903, 34087037, 340562, 36167901, 3616793, 36167956, 327517
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9615 using three electrodes per touch switch
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe
• CPC Class Codes: H03K 2217/960775 Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes

Abstract

A capacitive sensor device for approach and/or contact detection can be coupled with an electric circuit (10) and has a sensor electronics (20) and a device for potential separation (30), which with the sensor electronics (20) is coupled and by which the capacitive sensor device can be coupled with the electric circuit (10). In a method for operating a capacitive sensor device which has a sensor electronics, the sensor electronics can be coupled with an electric circuit and the sensor electronics is coupled with the electric circuit in a separable way with respect to the potential.

Claims

1. A capacitive sensor device for approach and/or contact detection, configured to be coupled with an electric circuit, wherein the electric circuit is coupled with a power supply, comprising

an electrode configuration, having at least one transmission electrode, at least one compensation electrode and at least one receiving electrode, in which the transmission electrode and the compensation electrode are configured to each emit an alternating electrical field which is coupled into the receiving electrode,

a sensor-electronics configured to be coupled with the electrode configuration and which, at least during a measuring interval, supplies the transmission electrode and the compensation electrode each with an electric alternating signal and taps an electrical value at the receiving electrode, and

a device for potential separation having a primary side and a secondary side, wherein the secondary side is directly coupled with the sensor electronics and the primary side is coupled with the electric circuit and said power supply.

2. The sensor device according to claim 1, wherein the device for potential separation, at least during the measuring interval, galvanically separates the capacitive sensor device from the electric circuit.

3. The sensor device according to claim 1, wherein the device for potential separation galvanically separates the capacitive sensor device from the electric circuit in a time-division multiplex method.

4. The sensor device according to claim 1, wherein the device for potential separation comprises a filter for the frequency-selective separation of the capacitive sensor device from the electric circuit, preferably during the measuring interval.

5. The sensor device according to claim 1, wherein the device for potential separation comprises at least one of optical coupling device, capacitive coupling device, and inductive coupling device, in order to couple the capacitive sensor device with the electric circuit.

6. The sensor device according to claim 1, wherein the device for potential separation presents at least one electric switch, by which the sensor-electronics is configured to be coupled with the electric circuit.

7. The sensor device according to claim 1, wherein the sensor-electronics further supplies the transmission electrode with an electric alternating signal, which is phase-shifted with respect to the electric alternating signal supplied at the compensation electrode.

8. The sensor device according to claim 1, wherein the electric circuit is part of an electric hand-held device, especially of a mobile phone, a two-way radio, a computer mouse, a remote control device, a digital camera, a game controller, a movable minicomputer, or a tablet PC.

9. The sensor device according to claim 1, wherein the device for potential separation is configured to decouple the electric circuit and the sensor electronics during the measuring interval and to couple the electric circuit and the sensor electronics after the measuring interval.

10. The sensor device according to claim 1, wherein during the measuring interval the electric circuit and the sensor electronics are independently grounded.

11. The capacitive sensor device according to claim 1, wherein the sensor-electronics comprise an electrical charge storage which is charged by the power supply when a measurement cycle is not performed.

12. The capacitive sensor device according to claim 11, wherein the sensor-electronics store the measured electrical value for a time until they can be transmitted to the electric circuit.

13. A method for operating a capacitive sensor device, which comprises a sensor-electronics coupled with an electrode configuration, wherein the sensor-electronics is configured to be directly coupled with an electric circuit and a power supply, the method comprising:

providing at least during a measurement cycle a potential separation between the electric circuit coupled with the power supply and the sensor-electronics by a device for potential separation having a primary side and a secondary side, wherein the secondary side is directly coupled with the sensor electronics and the primary side is coupled with the electric circuit and said power supply;

supplying at least during each measurement cycle a first and second electric alternating signal by the sensor electronics to a transmission electrode and a compensation electrode of the electrode configuration, respectively to emit at them an alternating electrical field, which is coupled into a receiving electrode of the electrode configuration, wherein the receiving electrode provides for an electrical value to be measured.

14. The method according to claim 13, in which at least during the measuring cycle the capacitive sensor device is galvanically isolated from the electric circuit.

15. The method according to claim 13, wherein the capacitive sensor device is galvanically isolated from the electric circuit in a time-division multiplex method.

16. The method according to claim 13, wherein the potential separation is done with a device, which comprises at least one of optical coupling device, capacitive coupling device, inductive coupling device, and electric switch.

17. The method according to claim 13, wherein the sensor-electronics comprise an electrical charge storage which is charged by the power supply when a measurement cycle is not performed.

18. The method according to claim 17, wherein the sensor-electronics store the measured electrical value for a time until they can be transmitted to the electric circuit.

19. A mobile device comprising:

a capacitive sensor device for approach and/or contact detection, which is configured to be coupled with an electric circuit and a power supply of the mobile device, wherein the electric circuit comprises a microprocessor, wherein the capacitive sensor device comprises;

an electrode configuration, having at least one transmission electrode, at least one compensation electrode and at least one receiving electrode, and

a sensor-electronics coupled with the electrode configuration and which, at least during a measuring interval, supplies the transmission electrode and the compensation electrode each with an electric alternating signal, respectively and receives an electrical value from the receiving electrode, and

a device for potential separation comprising a primary side coupled with the electric circuit and the power supply and a secondary side directly coupled with the sensor-electronics wherein the device for potential separation is configured to provide at least during each measurement cycle a potential separation between the primary and secondary side.

20. The mobile device according to claim 19, wherein the device for potential separation, at least during the measuring interval, galvanically separates the capacitive sensor device from the electric circuit.

21. The mobile device according to claim 19, wherein the device for potential separation galvanically separates the capacitive sensor device from the electric circuit in a time-division multiplex method.

22. The mobile device according to claim 19, wherein the device for potential separation comprises a filter for the frequency-selective separation of the capacitive sensor device from the electric circuit, preferably during the measuring interval.

23. The mobile device according to claim 19, wherein the device for potential separation comprises at least one of optical coupling device, capacitive coupling device, and inductive coupling device, in order to couple the capacitive sensor device with the electric circuit.

24. The mobile device according to claim 19, wherein the device for potential separation presents at least one electric switch, by which the sensor-electronics is configured to be coupled with the electric circuit.

25. The mobile device according to claim 19, wherein the sensor-electronics further supplies the transmission electrode with an electric alternating signal, which is phase-shifted with respect to the electric alternating signal supplied at the compensation electrode.

26. The mobile device according to claim 19, wherein the mobile device is a mobile phone, a two-way radio, a computer mouse, a remote control device, a digital camera, a game controller, a laptop computer, or a tablet PC.

27. The mobile device according to claim 19, wherein the sensor-electronics comprise an electrical charge storage which is charged by the power supply when a measurement cycle is not performed.

28. The sensor device according to claim 27, wherein the sensor-electronics store the measured electrical value for a time until they can be transmitted to the electric circuit.