SNR-aware active mode touch scans with electrode reallocation

• US 10,037,100 B2
• Filed: 06/19/2015
• Issued: 07/31/2018
• Est. Priority Date: 03/02/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Nayyar, Amit, Shahparnia, Shahrooz
• Primary Examiner(s): CRAWLEY, KEITH L
• Application Number:
  US14/745,344
• Publication Number:
  US 20160259467A1
• Time in Patent Office: 1,138 Days
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• 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

Abstract

A touch controller can dynamically balance performance criteria, such as signal-to-noise ratio (SNR) thresholds, with power consumption for touch sensitive devices. A touch controller can be configured to reduce power consumption by reconfiguring bank boundaries for an active mode scan so as to reduce the number of banks scanned with a banked active mode scan. Additionally or alternatively, the stimulation signal amplitude and integration time of the touch controller can be dynamically adjusted to balance performance criteria with power consumption. Default integration times and default stimulation signal amplitudes can be increased in higher-noise operating environments to raise SNR, and can be reduced to save power in lower-noise operating environments. Additionally or alternatively, the touch scanning rate of the touch controller can be dynamically adjusted to reduce power consumption of the touch sensitive device or to reallocate touch sensing frames to increase integration times and thereby SNR performance.

Claims

1. A method for reducing power consumption of a touch controller comprising:

performing banked scans of a plurality of first banks, each of the plurality of first banks allocated a respective plurality of electrodes;

detecting one or more touch events from the banked scans of the plurality of first banks; and

in response to detecting the one or more touch events;

in accordance with a determination that one or more first criteria are satisfied when the one or more touch events correspond to one or more objects touching or proximate over two, and not more than two, of the plurality of first banks, wherein the two of the plurality of first banks are adjacent banks;

reallocating a subset of the respective plurality of electrodes of one of the two of the plurality of first banks and a subset of the respective plurality of electrodes of a second of the two of the plurality of first banks to a second bank;

reallocating a remaining subset of the respective plurality of electrodes of the one of the two of the plurality of first banks and a remaining subset of the respective plurality of electrodes of the second of the two of the plurality of first banks to one or more third banks;

performing a banked active mode scan of electrodes reallocated to the second bank; and

performing, for each respective third bank of the one or more third banks, a banked common mode scan of all electrodes reallocated to the respective third bank; and

in accordance with a determination that the one or more first criteria are not satisfied when the one or more touch events correspond to the one or more objects touching or proximate over three or more of the plurality of first banks;

performing, for each respective first bank of the plurality of first banks, a banked active mode scan of the respective plurality of electrodes allocated to the plurality of first banks.

2. The method of claim 1, further comprising:

in accordance with the determination that the one or more first criteria are satisfied, allocating adjacent electrodes from the two of the plurality of first banks such that the second bank is centered around a centroid of the detected one or more touch events.

3. The method of claim 1, wherein the second bank is the same size as each of the two of the plurality of first banks.

4. The method of claim 1, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, stimulating the respective plurality of electrodes of the respective first bank with a common mode stimulation signal to detect a coarse location of the touch event within a region of a touch sensor panel corresponding to the respective first bank.

5. The method of claim 1, further comprising:

performing a self-capacitance scan of a touch sensor panel to detect a coarse location of the one or more touch events touching or proximate to the touch sensor panel.

6. The method of claim 1, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, simultaneously stimulating the respective plurality of electrodes with a first plurality of stimulation signals in a first plurality of stimulation steps to detect a first fine location of the touch event within a region of a touch sensor panel corresponding to the respective first bank.

7. The method of claim 6, wherein performing the banked active mode scan of the electrodes reallocated to the second bank comprises simultaneously stimulating the reallocated electrodes of the second bank with a second plurality of stimulation signals having different phases during a second plurality of stimulation steps to determine a second fine location of the touch event within a region of a touch sensor panel corresponding to the second bank.

8. An electronic device comprising:

a touch-sensitive display; and

a touch controller coupled to the touch-sensitive display and configured to;

perform banked scans of a plurality of first banks, each of the plurality of first banks allocated a respective plurality of electrodes;

detect one or more touch events from the banked scans of the plurality of first banks; and

in response to detecting the one or more touch events;

in accordance with a determination that one or more first criteria are satisfied when the one or more touch events correspond to one or more objects touching or proximate over two, and not more than two, of the plurality of first banks, wherein the two of the plurality of first banks are adjacent banks;

reallocate a subset of the respective plurality of electrodes of one of the two of the plurality of first banks and a subset of the respective plurality of electrodes of a second of the two of the plurality of first banks to a second bank;

reallocate a remaining subset of the respective plurality of electrodes of the one of the two of the plurality of first banks and a remaining subset of the respective plurality of electrodes of the second of the two of the plurality of first banks to one or more third banks;

perform a banked active mode scan of electrodes reallocated to the second bank; and

perform, for each respective third bank of the one or more third banks, a banked common mode scan of all electrodes reallocated to the respective third bank; and

in accordance with a determination that the one or more first criteria are not satisfied when the one or more touch events correspond to the one or more objects touching or proximate over three or more of the plurality of first banks;

perform, for each respective first bank of the plurality of first banks, a banked active mode scan of the respective plurality of electrodes allocated to the plurality of first banks.

9. The electronic device of claim 8, wherein the respective plurality of electrodes are allocated equally among the plurality of first banks.

10. The electronic device of claim 8, the touch controller further configured to:

in accordance with the determination that the one or more first criteria are satisfied, allocate adjacent electrodes from the two of the plurality of first banks such that the second bank is centered around a centroid of the detected one or more touch events.

11. The electronic device of claim 8, wherein the second bank is the same size as each of the two of the plurality of first banks.

12. The electronic device of claim 8, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, stimulating the respective plurality of electrodes of the respective first bank with a common mode stimulation signal to detect a coarse location of the touch event within a region of the touch-sensitive display corresponding to the respective first bank.

13. The electronic device of claim 8, the touch controller further configured to:

perform a self-capacitance scan of the touch-sensitive display to detect a coarse location of the one or more touch events touching or proximate to the touch-sensitive display.

14. The electronic device of claim 8, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, simultaneously stimulating the respective plurality of electrodes with a first plurality of stimulation signals in a first plurality of stimulation steps to detect a first fine location of the touch event within a region of the touch-sensitive display corresponding to the respective first bank.

15. The electronic device of claim 14, wherein performing the banked active mode scan of the electrodes reallocated to the second bank comprises simultaneously stimulating the reallocated electrodes of the second bank with a second plurality of stimulation signals having different phases during a second plurality of stimulation steps to determine a second fine location of the touch event within a region of a touch-sensitive display corresponding to the second bank.

16. A non-transitory computer readable storage medium containing instructions that, when executed by a processor, can perform a method for reducing power consumption of a touch controller, the method comprising:

performing banked scans of a plurality of first banks, each of the plurality of first banks allocated a respective plurality of electrodes;

detecting one or more touch events from the banked scans of the plurality of first banks; and

in response to detecting the one or more touch events;

in accordance with a determination that one or more first criteria are satisfied when the one or more touch events correspond to one or more objects touching or proximate over two, and not more than two, of the plurality of first banks, wherein the two of the plurality of first banks are adjacent banks;

reallocating a subset of the respective plurality of electrodes of one of the two of the plurality of first banks and a subset of the respective plurality of electrodes of a second of the two of the plurality of first banks to a second bank;

reallocating a remaining subset of the respective plurality of electrodes of the one of the two of the plurality of first banks and a remaining subset of the respective plurality of electrodes of the second of the two of the plurality of first banks to one or more third banks;

performing a banked active mode scan of electrodes reallocated to the second bank; and

performing, for each respective third bank of the one or more third banks, a banked common mode scan of all electrodes reallocated to the respective third bank; and

in accordance with a determination that the one or more first criteria are not satisfied when the one or more touch events correspond to the one or more objects touching or proximate over three or more of the plurality of first banks;

performing, for each respective first bank of the plurality of first banks, a banked active mode scan of the respective plurality of electrodes allocated to the plurality of first banks.

17. The non-transitory computer readable storage medium of claim 16, further comprising:

in accordance with the determination that the one or more first criteria are satisfied, allocating adjacent electrodes from the two of the plurality of first banks such that the second bank is centered around a centroid of the detected one or more touch events.

18. The non-transitory computer readable storage medium of claim 16, wherein the second bank is the same size as each of the two of the plurality of first banks.

19. The non-transitory computer readable storage medium of claim 16, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, stimulating the respective plurality of electrodes of the respective first bank with a common mode stimulation signal to detect a coarse location of the touch event within a region of a touch sensor panel corresponding to the respective first bank.

20. The non-transitory computer readable storage medium of claim 16, further comprising:

performing a self-capacitance scan of a touch sensor panel to detect a coarse location of the one or more touch events touching or proximate to the touch sensor panel.

21. The non-transitory computer readable storage medium of claim 16, wherein the banked scans of the plurality of first banks comprises, for each respective first bank of the plurality of first banks, simultaneously stimulating the respective plurality of electrodes with a first plurality of stimulation signals in a first plurality of stimulation steps to detect a first fine location of the touch event within a region of a touch sensor panel corresponding to the respective first bank.

22. The non-transitory computer readable storage medium of claim 21, wherein performing the banked active mode scan of the electrodes reallocated to the second bank comprises simultaneously stimulating the reallocated electrodes of the second bank with a second plurality of stimulation signals having different phases during a second plurality of stimulation steps to determine a second fine location of the touch event within a region of a touch sensor panel corresponding to the second bank.