Parallel acquisition and measurement of capacitive sensor channels, and related systems, methods, and devices

Patent metadata

Field	Value
Publication number	US-10877608-B2
Application number	US-201816014969-A
Country	US
Kind code	B2
Filing date	Jun 21, 2018
Priority date	Jun 21, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

Embodiments of the disclosure relate, generally, to techniques for parallel acquisition and measurements and related circuits, systems and devices that implement those techniques. A technique for parallel acquisition and measurement generally includes simultaneously acquiring sensed signals from multiple sensor channels and determining channel capacitance measurements responsive to the sensed signals.

First claim

We claim:

1. A capacitive circuit system, comprising:
a sensor circuitry comprising drive lines and sense lines;
an acquisition circuitry operatively coupled to the sense lines; and
a digital logic circuitry configured to:
provide groups of drive signals to an interface operatively coupled to the drive lines of the sensor circuitry, wherein the groups of drive signals comprise polarity changes and the groups of drive signals are associated with a number of drive lines;
select active sense lines of the sensor circuitry; and
determine at least one channel capacitance of at least one active sense line responsive to one or more sample voltages and the polarity changes.

2. The capacitive circuit system of claim 1 , wherein the digital logic circuitry is configured to provide the groups of drive signals for a number of acquisition cycles.

3. The capacitive circuit system of claim 2 , wherein each group of the groups of drive signals is associated with a different acquisition cycle of the number of acquisition cycles.

4. The capacitive circuit system of claim 1 , wherein each of the polarity changes is selected from the group consisting of a low-to-high polarity change and a high-to-low polarity change.

5. The capacitive circuit system of claim 1 , wherein the number of drive lines is a subset of the drive lines of the sensing circuitry.

6. The capacitive circuit system of claim 1 , wherein the number of drive lines is all of the drive lines of the sensing circuitry.

7. The capacitive circuit system of claim 1 , wherein a number of groups of drive signals is equal to a number of acquisition cycles over which the one or more sample voltages are received.

8. The capacitive circuit system of claim 1 , further comprising selection circuitry configured to selectively couple selected sense lines to the acquisition circuitry responsive to selection by the digital logic circuitry.

9. The capacitive circuit system of claim 1 , further comprising selection circuitry, wherein the selection circuitry further comprises switches configured for selectively coupling, wherein the switches are selected from the group consisting of bipolar-junction-transistors, diodes, capacitive switches, metal oxide semiconductor field effect transistors, and insulated gate bipolar transistors.

10. The capacitive circuit system of claim 1 , wherein the acquisition circuitry comprises charge-to-voltage converter circuitry.

11. A capacitive circuit system, comprising:
a sensor circuitry comprising drive lines and sense lines;
an acquisition circuitry operatively coupled to the sense lines; and
a digital logic circuitry configured to:
provide groups of drive signals to an interface operatively coupled to the drive lines of the sensor circuitry,
wherein the groups of drive signals are associated with a number of drive lines, and
wherein a first group of drive signals associated with a first acquisition cycle comprises first drive signals, and one drive signal of the first drive signals comprises a first polarity change and all other drive signals of the first drive signals comprise a second polarity change,

select active sense lines of the sensor circuitry; and
determine at least one channel capacitance of at least one active sense line responsive to one or more sample voltages and the polarity changes.

12. The capacitive circuit system of claim 11 , wherein the one drive signal of the first group of drive signals is associated with a first drive line of the number of drive lines.

13. The capacitive circuit system of claim 11 , wherein a second group of drive signals associated with a second acquisition cycle comprises second drive signals, and one drive signal of the second drive signals comprises the first polarity change and all other drive signals of the drive signals comprise the second polarity change.

14. The capacitive circuit system of claim 13 , wherein the one drive signal of the second drive signals is associated with a second drive line of the number of drive lines.

15. The capacitive circuit system of claim 14 , wherein the first acquisition cycle and the second acquisition cycle are consecutive.

16. A method of capacitive sensing, comprising:
asserting, at a number of drive lines of a sensor circuitry, groups of drive signals comprising polarity changes;
enabling reception of sensed signals from sense lines of the sensor circuitry while the groups of drive signals are asserted;
receiving one or more sample voltages indicative of the sensed signals; and
determining at least one channel capacitance of at least one of the sense lines responsive to the one or more sample voltages.

17. The method of claim 16 , further comprising asserting the groups of drive signals over a number of acquisition cycles.

18. The method of claim 17 , further comprising asserting each group of the groups of drive signals a different acquisition cycle of the number of acquisition cycles.

19. The method of claim 16 , wherein each of the polarity changes is selected from a group consisting of a low-to-high signal change and a high-to-low signal change.

20. The method of claim 16 , further comprising asserting the groups of drive signals at a subset of the number of drive lines of the sensing circuitry.

21. The method of claim 16 , further comprising asserting the groups of drive signals at all of the number of drive lines of the sensing circuitry.

22. The method of claim 16 , further comprising asserting drive signals of all of the groups over a number of acquisition cycles equal to the number of groups.

23. The method claim 16 , further comprising selectively coupling selected sense lines to an acquisition circuitry.

24. The method of claim 23 , further comprising selectively enabling or disabling switches to selectively couple the selected sense lines to the acquisition circuitry, wherein the switches are selected from the group consisting of bipolar-junction-transistors, diodes, capacitive switches, metal oxide semiconductor field effect transistors, and insulated gate bipolar transistors.

25. The method of claim 16 , further comprising integrating the sensed signals at a charge-to-voltage converter configured to output a measurable voltage responsive to the integrated sensed signals.

26. A method of capacitive sensing, comprising:
asserting, at a number of drive lines of a sensor circuitry, groups of drive signals comprising polarity changes, wherein the asserting the groups of drive signals comprises:
asserting first drive signals during a first acquisition cycle, wherein one drive signal of the first drive signals comprises a first polarity change and all other drive signals of the drive signals comprise a second polarity change;

enabling reception of sensed signals from sense lines of the sensor circuitry while the groups of drive signals are asserted;
receiving one or more sample voltages indicative of the sensed signals; and
determining at least one channel capacitance of at least one of the sense lines responsive to the one or more sample voltages,
further comprising asserting first drive signals during a first acquisition cycle, wherein one drive signal of the first drive signals comprises a first polarity change and all other drive signals of the drive signals comprise a second polarity change.

27. The method of claim 26 , further comprising asserting the one drive signal of the first drive s

Assignees

• Microchip Tech Inc

Inventors

• Vix Regis
• Whelan Rian
• Igier Frederic

Classifications

• G06F3/04886

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• G06F2203/04104

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• G06F3/0446

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