Sensor system and method for reducing a settling time of a sensor system

• US 9,476,924 B2
• Filed: 12/06/2012
• Issued: 10/25/2016
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Original Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Inventors: Ivanov, Artem, Zhang, Ce
• Primary Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US14/363,938
• Publication Number:
  US 20150097585A1
• Time in Patent Office: 1,419 Days
• Field of Search: 324/600, 324/649, 324/658, 324/660, 324/661, 324/679, 324/684, 324/686, 702/47, 702/52
• US Class Current: 1/1
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard

Abstract

A sensor system has a first sensor device and a second capacitive sensor device for detecting a movement of the object relative to a detection surface, wherein the sensor system is configured to be operated in a first mode of operation and in a second mode of operation, wherein the sensor system is configured to be switched over from the first mode of operation into the second mode of operation, wherein the second capacitive sensor device has a number of second sensor electrodes, and wherein in the sensor system at least in the second mode of operation at least one signal path connectable with a predetermined fixed electric potential is provided, which is parallel to a parasitic capacitance of the first sensor device.

Claims

1. A sensor system comprising a first sensor device and a second capacitive sensor device configured to detect a movement of an object relative to a detection surface without touching it, wherein the sensor system is configured to be operated in a first mode of operation using the first sensor device and in a second mode of operation using the second sensor device, wherein the sensor system is configured to be switched over from the first mode of operation into the second mode of operation, wherein the second capacitive sensor device comprises a number of second sensor electrodes, and wherein in the sensor system at least in the second mode of operation at least one signal path connected with a predetermined fixed electric potential is connected in parallel with a parasitic capacitance connected with an input of the first sensor device.

2. The sensor system of claim 1, wherein the predetermined fixed electric potential comprises at least one of ground potential, supply voltage, half of the supply voltage, and an electric potential between ground potential and supply voltage.

3. The sensor system of claim 1, wherein the signal path is connected with the predetermined electric potential via an electric resistance.

4. The sensor system of claim 3, wherein through the signal path at least one terminal of the first sensor device is coupled with the predetermined electric potential via the electric resistance.

5. The sensor system of claim 1, wherein the first sensor device comprises a capacitive sensor device configured to detect a contact by an object with a detection surface, wherein the first capacitive sensor device comprises a number of first sensor electrodes, wherein in the first mode of operation a contact of an object is detected, and wherein in the second mode of operation a non-touching movement of an object is detected.

6. The sensor system of claim 5, wherein through the signal path at least one electrode of the first sensor electrodes is coupled with the predetermined electric potential via an electric resistance.

7. The sensor system of claim 1, wherein a switching device is provided in the signal path that is designed to connect the signal path with the predetermined fixed electric potential in the second mode of operation.

8. The sensor system of claim 5, wherein through the signal path at least those first sensor electrodes are each coupled via one electric resistance with the predetermined electric potential, whose distance from the second sensor electrodes is below a predetermined value.

9. A method for reducing a settling time of a second capacitive sensor device, the method comprising:

detecting a movement of an object relative to a detection surface without touching it, wherein the second capacitive sensor device is part of a sensor system that in addition comprises a first sensor device; and

operating the sensor system in a first mode of operation using the first sensor device or in a second mode of operation using the second sensor device,

wherein at least in the second mode of operation, connecting at least one signal path with a predetermined fixed electric potential in the sensor system, and

wherein connecting the at least one signal path comprises connecting the at least one signal path in parallel to the parasitic capacitance connected with an input of the first sensor device.

10. The method of claim 9, wherein:

the first sensor device comprises a capacitive sensor device configured to detect a contact by an object with a detection surface;

wherein

the first capacitive sensor device comprises a number of first sensor electrodes;

in the first mode of operation, detecting a contact; and

in the second mode of operation, detecting the non-touching movement.

11. The method of claim 10, further comprising connecting at least one terminal of the first capacitive sensor device with the predetermined electric potential via the electric resistance through the at least one signal path.

12. The method of claim 10, wherein through the signal path at least one electrode of the sensor electrodes of the first capacitive sensor device is connected with the predetermined electric potential via the electric resistance.

13. The method of claim 9, connecting the at least one signal path comprises connecting the at least one signal path with the predetermined electric potential via an electric resistance.