Capacitive sensing button on chip

• US 9,588,626 B2
• Filed: 02/26/2015
• Issued: 03/07/2017
• Est. Priority Date: 02/28/2011
• Status: Active Grant

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Narayanasamy, Rajagopal, Swamy, Mahadevan Krishnamurthy Narayana, Wright, David G., Kolokowsky, Steve
• Primary Examiner(s): He, Amy
• Application Number:
  US14/632,191
• Publication Number:
  US 20150293625A1
• Time in Patent Office: 740 Days
• Field of Search: 324/686, 345/173, 345/174
• US Class Current: 1/1
• CPC Class Codes: G01D 5/2405 by varying dielectric
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H03K 17/602 in integrated circuits
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/960715 Rc-timing; e.g. measurement of variation of charge time or discharge time of the sensor
• CPC Class Codes: H03K 2217/960725 Charge-transfer
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches

Abstract

A method and apparatus include a plurality of sensor elements arranged within an integrated circuit package and a controller arranged within the integrated circuit package and coupled to the plurality of sensor elements. The controller is configured to apply a transmit signal to a first sensor element of the plurality of sensor elements and receive a receive signal from a second sensor element of the plurality of sensor elements. The receive signal represents a mutual capacitance of the first sensor element and the second sensor element.

Claims

1. An integrated circuit package comprising:

a plurality of sensor elements arranged within the integrated circuit package; and

a controller arranged within the integrated circuit package and coupled to the plurality of sensor elements, wherein the controller is configured to apply a transmit signal to a first sensor element of the plurality of sensor elements and receive a receive signal from a second sensor element of the plurality of sensor elements, the receive signal representing a mutual capacitance of the first sensor element and the second sensor element.

2. The integrated circuit package of claim 1, wherein the plurality of sensor elements includes a central sensor element and a subset of sensor elements arranged around the central sensor element, wherein the mutual capacitance is between the central sensor element and at least one of the subset of sensor elements.

3. The integrated circuit package of claim 1, wherein the controller is configured to detect sequential changes in mutual capacitance of the plurality of sensor elements.

4. The integrated circuit package of claim 3, wherein the plurality of sensor elements are arranged to implement at least one of a linear slider and a scroll wheel.

5. The integrated circuit package of claim 1, wherein the controller is configured to apply transmit signals to a first subset of sensor elements of the plurality of sensor elements and to receive receive signals from a second subset of the plurality of sensor elements.

6. The integrated circuit package of claim 5, wherein the controller is configured to use the receive signals to determine a position of a conductive object.

7. The integrated circuit of claim 1, wherein the controller is configured receive a further receive signal from the second sensor element, wherein the further receive signal represents a self capacitance of the second sensor element, wherein the controller is configured to use the receive signal and the further receive signal to detect a presence of a conductive object.

8. The integrated circuit package of claim 1, further comprising an output pin coupled to the controller, the output pin configured to carry a signal that is based on the mutual capacitance and is associated with a conductive object.

9. The integrated circuit package of claim 1, further comprising a top layer overlying the plurality of sensor elements.

10. The integrated circuit package of claim 1, wherein the controller is formed on a die mounted underneath the sensor element.

11. The integrated circuit package of claim 1, further comprising a lead frame coupled to the controller and configured to secure a substrate of the plurality of sensor elements.

12. A system comprising:

a device including user interface circuitry; and

a circuit package coupled to the user interface circuitry, the circuit package comprising;

a plurality of sensor elements located within the circuit package; and

a logic circuitry located within the circuit package and coupled to the plurality of sensor elements, wherein the logic circuitry is configured to apply a transmit signal to a first sensor element of the plurality of sensor elements and receive a receive signal from a second sensor element of the plurality of sensor elements, the receive signal representing a mutual capacitance of the first sensor element and the second sensor element.

13. The system of claim 12, wherein the logic circuitry is configured to detect sequential changes in mutual capacitance of the plurality of sensor elements.

14. The system of claim 13, wherein the plurality of sensor elements are arranged to implement at least one of a linear slider and a scroll wheel.

15. The system of claim 12, wherein the circuit package is configured to replace an interface component of the interface circuitry.

16. The system of claim 12, wherein the circuit package further comprises an output pin coupled to the logic circuitry, the output pin configured to carry a signal that is based on the mutual capacitance and is associated with a conductive object proximate to the first sensor element and the second sensor element.

17. The system of claim 12, wherein the circuit package further comprises a lead frame coupled to the logic circuitry and configured to secure a substrate of the plurality of sensor elements.

18. A method comprising:

applying a transmit signal, from within an integrated circuit package, to a first sensor element of a plurality of sensor elements arranged within the integrated circuit package; and

receiving a receive signal, within the integrated circuit package, from a second sensor element of the plurality of sensor elements, wherein the receive signal represents a mutual capacitance of the first sensor element and the second sensor element.

19. The method of claim 18, comprising using the receive signal to implement a button function.

20. The method of claim 18 comprising:

applying at least one further transmit signal, from within the integrated circuit package, to one of the first sensor element and a third sensor element;

receiving at least one further receive signal, within the integrated circuit package, from one of the second sensor element and a fourth sensor element; and

using the receive signal and the further receive signal to implement one of a slider function and a scrolling function.