Touch panel having a master and slave controller and method for driving thereof

• US 9,268,432 B2
• Filed: 10/19/2012
• Issued: 02/23/2016
• Est. Priority Date: 10/19/2012
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Asia Pacific Pte Limited (STMicroelectronics NV)
• Inventors: Guo, Dianbo, Tan, KienBeng
• Primary Examiner(s): Pham, Long D
• Application Number:
  US13/656,302
• Publication Number:
  US 20140111443A1
• Time in Patent Office: 1,222 Days
• Field of Search: 345/173
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers

Abstract

In accordance with an embodiment, a method of operating a touch panel includes operating a slave touch panel controller by receiving a synchronization signal from a master touch panel controller of a display driver circuit, and polling a plurality of receive inputs coupled to outputs of an in-cell touch module based on an predetermined pattern.

Claims

1. A method of operating a touch panel, the method comprising:

operating a slave touch panel controller, operating the slave touch panel controller comprising

receiving a single synchronization pulse from a master touch panel controller of a display driver circuit, wherein the master touch panel controller is configured to generate and transmit a plurality of force signals according to a first predetermined pattern that defines an order in which the plurality of force signals are transmitted to an in-cell touch module, and the master touch panel controller is configured to generate the single synchronization pulse a first period of time after at least one of a horizontal synchronization signal and a vertical synchronization signal is asserted, and

upon receipt of the single synchronization pulse, polling a plurality of receive inputs coupled to outputs of the in-cell touch module according to a second predetermined pattern, wherein the second predetermined pattern defines an order in which the plurality of receive inputs are polled, the second predetermined pattern corresponds to the first predetermined pattern, and the polling is initiated upon receipt of only the single synchronization pulse.

2. The method of claim 1, further comprising determining a selected coordinate of the in-cell touch module based on the polling.

3. The method of claim 1, further comprising setting the second predetermined pattern.

4. The method of claim 3, wherein setting the second predetermined pattern comprises receiving configuration information via a digital interface.

5. The method of claim 1, further comprising operating the master touch panel controller of the display driver circuit, operating the master touch panel controller comprising:

transmitting the single synchronization pulse to the slave touch panel controller;

generating the plurality of force signals; and

transmitting the plurality of force signals to the in-cell touch module.

6. The method of claim 5, wherein transmitting the single synchronization pulse comprises transmitting the single synchronization pulse from a first integrated circuit comprising the master touch panel controller to a second integrated circuit comprising the slave touch panel controller.

7. The method of claim 5, wherein transmitting the single synchronization pulse comprises transmitting the single synchronization pulse from a first circuit comprising the master touch panel controller on a first integrated circuit to a second circuit comprising the slave touch panel controller on the first integrated circuit.

8. An in-cell touch panel controller circuit comprising:

a plurality of receiver inputs configured to be coupled to touch panel output signals of an in-cell touch panel circuit of an integrated in-cell touch panel display; and

a slave touch panel controller coupled to the plurality of receiver inputs and to a single synchronization input configured to be coupled to a master touch panel controller of a display driver circuit, wherein

the master touch panel controller is configured to generate and transmit a single synchronization pulse and a plurality of force signals according to a first predetermined pattern that defines an order in which the plurality of force signals are transmitted to the integrated in-cell touch panel display, and the master touch panel controller is configured to generate the single synchronization pulse a first period of time after at least one of a horizontal synchronization signal and a vertical synchronization signal is asserted, and

the slave touch panel controller is configured to poll the plurality of receive inputs according to a second predetermined pattern upon receipt of the single synchronization pulse on the single synchronization input, wherein the second predetermined pattern defines an order in which the plurality of receive inputs are polled, the second predetermined pattern corresponds to the first predetermined pattern, and the slave touch panel controller is configured to initiate polling the plurality of receive inputs upon receipt of only the single synchronization pulse.

9. The circuit of claim 8, further comprising a serial interface coupled to the slave touch panel controller, the serial interface configured to receive configuration data to set the second predetermined pattern.

10. The circuit of claim 9, wherein the slave touch panel controller further comprises a pattern configuration register coupled to the serial interface, wherein contents of the pattern configuration register affects the second predetermined pattern.

11. The circuit of claim 8, wherein the slave touch panel controller is further configured to provide touch panel position data based on the polled plurality of receive inputs.

12. The circuit of claim 8, wherein the plurality of receive inputs and the slave touch panel controller is disposed on a first integrated circuit.

13. The circuit of claim 12, wherein the master touch panel controller is disposed on a second integrated circuit separate from the first integrated circuit.

14. The circuit of claim 12, further comprising the master touch panel controller.

15. The circuit of claim 14, wherein the master touch panel controller is disposed on the first integrated circuit.

16. The circuit of claim 14, wherein the master touch panel controller comprises a plurality of forcing outputs configured to be coupled to forcing inputs of the integrated in-cell touch panel display.

17. The circuit of claim 14, further comprising a plurality of charge amplifiers coupled to the plurality of receive inputs.

18. An integrated in-cell display system comprising:

an integrated in-cell display comprising a plurality of touch panel forcing inputs, a plurality of display inputs, and a plurality of touch panel sensor outputs;

a first integrated circuit comprising a display driver coupled to the plurality of display inputs and a master touch panel controller coupled to the plurality of touch panel forcing inputs, the master touch panel controller configured to generate forcing signals on the plurality of touch panel forcing inputs according to a first predetermined pattern that defines an order in which forcing signals are transmitted via the plurality of touch panel forcing inputs to the integrated in-cell display and generate a single synchronization pulse on a single synchronization output, wherein the first integrated circuit is configured to generate the single synchronization pulse a first period of time after at least one of a horizontal synchronization signal and a vertical synchronization signal is asserted; and

a second integrated circuit comprising a slave touch panel controller having a single synchronization input coupled to the single synchronization output of the master touch panel controller, and a plurality of receive inputs coupled to the plurality of touch panel sensor outputs, wherein the slave touch panel controller is configured to poll the plurality of receive inputs according to a second predetermined pattern upon receipt of the single synchronization pulse from the master touch panel controller, wherein the second predetermined pattern defines an order in which the plurality of receive inputs are polled, the second predetermined pattern corresponds to the first predetermined pattern, and the slave touch panel controller is configured to initiate polling the plurality of receive inputs upon receipt of only the single synchronization pulse.

19. The system of claim 18, wherein the first integrated circuit and the second integrated circuit comprises separate integrated circuits.

20. The system of claim 18, wherein the slave touch panel controller further comprises a serial interface coupled to a pattern configuration register, the pattern configuration register configured to determine the second predetermined pattern.

21. The system of claim 18, wherein the first integrated circuit comprises a plurality of level shifting drivers having inputs coupled to the master touch panel controller and outputs coupled to the plurality of touch panel forcing inputs.