SEMICONDUCTOR DEVICE AND ELECTRONIC DEVICE

• US 20140145985A1
• Filed: 11/21/2013
• Published: 05/29/2014
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: Omnivision TDDI Ontario Limited Partnership
• Original Assignee: Renesas SP Drivers Inc. (Synaptics Incorporated)
• Inventors: Akai, Akihito, Kuroiwa, Tsuyoshi, Ishii, Tatsuya
• Granted Patent: US 9,568,976 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

The semiconductor device has a touch panel controller, a processor and a display driver. The semiconductor device is arranged so as to reduce an electric power uselessly consumed while the action of the display driver is stopped or suspended and further, and an electric power uselessly consumed by the touch-detecting action for recovery of the display driver from the state of the action being stopped or suspended.

The processor built in the semiconductor device together with the touch panel controller and the display driver returns to its workable state from Sleep state each time a given length of time elapses, and then causes the touch panel to perform a touch-detecting action. When the processor cannot acquire a result of judgment as “being touched”, it returns to Sleep state again, and waits for the given length of time to elapse.

Claims

1. A semiconductor device comprising:

a touch panel controller operable to perform pulse-drive control on one electrodes of a touch panel and detection control of touch signals arising on the other electrodes capacitively coupling with the one electrodes;

a processor operable to perform control of the touch panel controller; and

a display driver operable to perform drive control of a display panel,

wherein the processor returns to its workable state from Sleep state each time a given length of time elapses, causes the touch panel controller to perform an action of detecting a touch/no touch, and

when the processor cannot acquire a result of judgment as “

being touched”

, the processor returns to Sleep state again, and waits for a given length of time to elapse.

2. The semiconductor device according to claim 1, wherein the processor in Sleep state returns to its workable state from Sleep state each time the given length of time elapses, and

on receipt of the result of judgment as “

being touched”

, the processor takes an action for coping with an action from outside, and waits for a touch-scan-activation instruction from the touch panel controller, and the display driver waits for an activation instruction.

3. The semiconductor device according to claim 2, wherein a touch condition when the processor judges as “

being touched”

is that more than one touch position can be detected.

4. The semiconductor device according to claim 3, wherein the touch-scan-activation instruction includes an instruction for starting touch scan at intervals shorter than the given length of time, and

on receipt of the touch-scan-activation instruction, the processor performs a coordinate calculation of a touch position based on touch detection signals obtained by the touch panel.

5. The semiconductor device according to claim 1, wherein the touch panel controller has:

a plurality of drive terminals connected with the drive electrodes of the touch panel;

a first drive circuit operable to output a drive pulse from the drive terminals;

a plurality of detection terminals connected with the detection electrodes of the touch panel;

a second drive circuit operable to output a drive pulse to the detection terminals;

a detection circuit operable to accumulate signals input, more than once, through the detection terminals in synchronization with a change in the drive pulse thereby creating detection data; and

a timing control circuit operable to control a touch-detecting action by use of the first and second drive circuits and the detection circuit, and

the timing control circuit has a first touch detection mode in which detection data are created by accumulating, by use of the detection circuit, signals input more than once from the detection terminals in synchronization with a change of the drive pulse output by the first drive circuit, and

a second touch detection mode in which detection data are created by accumulating, by use of the detection circuit, signals input more than once from the detection terminals of one of groups consisting of the even and odd detection terminals respectively in synchronization with a change of the drive pulse output from the second drive circuit through the detection terminals of the other group.

6. The semiconductor device according to claim 5, wherein the action of detecting a touch/no touch which the processor returns to its workable state from Sleep state to cause the touch panel controller to perform each time a given length of time elapses is an action according to the second touch detection mode.

7. The semiconductor device according to claim 6, wherein the processor in Sleep state returns to its workable state from Sleep state each time the given length of time elapses,

when acquiring the result of judgment as “

being touched”

, the processor makes a request for interruption to outside, and waits for a touch-scan-activation instruction from the touch panel controller, and the display driver waits for an activation instruction, and

the touch-detecting action in response to the touch-scan-activation instruction is an action according to the first touch detection mode.

8. The semiconductor device according to claim 7, wherein a touch condition when the processor judges as “

being touched”

in the second touch detection mode is that more than one touch position can be detected.

9. The semiconductor device according to claim 8, wherein the touch-scan-activation instruction includes an instruction for starting touch scan at intervals shorter than the given length of time, and

on receipt of the touch-scan-activation instruction, the processor performs a coordinate calculation of a touch position based on touch detection signals obtained by the touch panel.

10. The semiconductor device according to claim 5, wherein the timing control circuit has a mode register capable of rewritably storing instruction data for providing an instruction on which of the first and second touch detection modes to select.

11. The semiconductor device according to claim 5, wherein the timing control circuit has a mode register capable of rewritably storing instruction data for providing an instruction on which group of the even and odd detection terminal groups to direct the drive pulse to, and on which group to accept detection signal input from.

12. The semiconductor device according to claim 5, wherein the second drive circuit includes:

a voltage-select switch circuit operable to alternately select voltages having different levels; and

a buffer amplifier operable to output, to the corresponding detection terminal, voltages output by the voltage-select switch circuit.

13. An electronic device comprising:

a host processor;

a touch panel having a plurality of drive electrodes, a plurality of detection electrodes, and capacitance components formed between the electrodes;

a touch panel controller operable to perform pulse-drive control on the one electrodes of the touch panel and detection control of touch signals arising on the other electrodes capacitively coupling with the one electrodes;

a processor connected with the host processor and operable to control the touch panel controller;

a display panel; and

a display driver connected with the host processor and operable to perform drive control of the display panel,

wherein the processor returns to its workable state from Sleep state each time a given length of time elapses, causes the touch panel controller to perform an action of detecting a touch/no touch, and

when the processor cannot acquire the result of judgment as “

being touched”

, the processor returns to Sleep state again, and waits for the given length of time to elapse.

14. The electronic device according to claim 13, wherein the processor in Sleep state returns to its workable state from Sleep state each time the given length of time elapses, and

on receipt of the result of judgment as “

being touched”

, the processor takes an action of dealing with the host processor, and waits for a touch-scan-activation instruction from the touch panel controller, and the display driver waits for an activation instruction from the host processor.

15. The electronic device according to claim 14, wherein a touch condition when the processor judges as “

being touched”

is that more than one touch position can be detected.

16. The electronic device according to claim 15, wherein the touch-scan-activation instruction includes an instruction for starting touch scan at intervals shorter than the given length of time, and

on receipt of the touch-scan-activation instruction, the processor performs a coordinate calculation of a touch position based on touch detection signals obtained by the touch panel.

17. The electronic device according to claim 13, wherein the touch panel controller has:

a plurality of drive terminals connected with the drive electrodes of the touch panel;

a first drive circuit operable to output a drive pulse from the drive terminals;

a plurality of detection terminals connected with the detection electrodes of the touch panel;

a second drive circuit operable to output a drive pulse to the detection terminals;

a detection circuit operable to accumulate signals input, more than once, through the detection terminals in synchronization with a change in the drive pulse thereby creating detection data; and

a timing control circuit operable to control a touch-detecting action by use of the first and second drive circuits and the detection circuit, and

the timing control circuit has a first touch detection mode in which detection data are created by accumulating, by use of the detection circuit, signals input more than once from the detection terminals in synchronization with a change of the drive pulse output by the first drive circuit, and

a second touch detection mode in which detection data are created by accumulating, by use of the detection circuit, signals input more than once from the detection terminals of one of groups consisting of the even and odd detection terminals respectively in synchronization with a change of the drive pulse output from the second drive circuit through the detection terminals of the other group.

18. The electronic device according to claim 17, wherein the action of detecting a touch/no touch which the processor returns to its workable state from Sleep state to cause the touch panel controller to perform each time the given length of time elapses is an action according to the second touch detection mode.

19. The electronic device according to claim 18, wherein the processor in Sleep state returns to its workable state from Sleep state each time the given length of time elapses,

when acquiring the result of judgment as “

being touched”

, the processor makes a request for interruption to outside, and waits for a touch-scan-activation instruction from the touch panel controller, and the display driver waits for an activation instruction from the host processor, and

the touch-detecting action in response to the touch-scan-activation instruction is an action according to the first touch detection mode.

20. The electronic device according to claim 19, wherein a touch condition when the processor judges as “

being touched”

in the second touch detection mode is that more than one touch position can be detected.

21. The electronic device according to claim 20, wherein the touch-scan-activation instruction includes an instruction for starting touch scan at intervals shorter than the given length of time, and

on receipt of the touch-scan-activation instruction, the processor performs a coordinate calculation of a touch position based on touch detection signals obtained by the touch panel.

22. The electronic device according to claim 17, wherein the timing control circuit has a mode register which receives, from the host processor, instruction data for providing an instruction on which of the first and second touch detection modes to select, and rewritably stores the instruction data.

23. The electronic device according to claim 17, wherein the timing control circuit has a mode register which receives, from the host processor, instruction data for providing an instruction on which group of the even and odd detection terminal groups to direct the drive pulse to, and on which group to accept detection signal input from, and rewritably stores the instruction data.