DISCONTINUOUS INTEGRATION USING HALF PERIODS

• US 20140022203A1
• Filed: 11/07/2012
• Published: 01/23/2014
• Est. Priority Date: 07/17/2012
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Roman Ogirko
• Inventors: Karpin, Oleksandr, Ribeiro, Milton, Bihday, Volodymyr, Ogirko, Roman, Maharyta, Andriy, Kolych, Igor
• Granted Patent: US 9,411,928 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

Apparatuses and methods of frequency hopping algorithms are described. One method monitors a signal on one or more electrodes of a sense network at a first operating frequency and detects noise in the signal at the first operating frequency. The method then switches to a second operating frequency, based on said detecting, for scanning the electrodes to detect a conductive object proximate to the plurality of electrodes, wherein a constant integration time is used for one half-period when scanning the electrodes at both the first and second operating frequencies.

Claims

1. A method comprising:

monitoring a signal on one or more electrodes of a sense network at a first operating frequency;

monitoring a signal on the one or more electrodes of the sense network at a second operating frequency; and

scanning, by a controller comprising a processing device and a memory, the one or more electrodes to detect a conductive object proximate to the sense network, wherein a constant integration time is used for one half-period when scanning the one or more electrodes at both the first and second operating frequencies.

2. The method of claim 1, further comprising:

detecting noise in the signal at the first operating frequency; and

switching to the second operating frequency, based on said detecting, wherein detecting noise in the signal comprises;

comparing a noise level to a first noise threshold; and

detecting noise if the noise level exceeds the first noise threshold.

3. The method of claim 2, wherein switching to a second operating frequency comprises selecting one of a plurality of operating frequencies defined by a frequency hopping algorithm, wherein the second operating frequency is the one of the plurality of operating frequencies with a lowest noise level.

4. The method of claim 1, wherein the constant integration time is defined in a single set of configuration data used for both the first and second operating frequencies.

5. The method of claim 1, further comprising:

detecting a high level of noise in the signal at the first operating frequency; and

decreasing the integration time when scanning the electrodes at the first operating frequency.

6. The method of claim 5, wherein detecting a high level of noise comprises:

comparing a noise level to a second noise threshold; and

detecting high noise if the noise level exceeds the second noise threshold.

7. The method of claim 5, further comprising:

decreasing the integration time to a reduced integration time with a specified relationship between the reduced integration time and a length of pauses between integrations.

8. A capacitance sensing system comprising:

a memory device storing calibration data; and

a controller coupled to the memory device, wherein the controller is configured to receive signals from a sense network comprising a plurality of electrodes to detect a conductive object proximate to the plurality of electrodes, wherein the controller comprises;

a noise listening circuit configured to monitor the plurality of electrodes during a first mode of operation and during a second mode of operation; and

a sense control circuit configured to scan the plurality of electrodes to detect the conductive object, wherein the controller uses a same calibration data when operating at both the first and second modes of operation.

9. The capacitance sensing system of claim 8, wherein the sense control circuit is further configured to:

switch the controller from the first mode of operation to the second mode of operation in response to the noise listening circuit detecting a noise level in the first mode of operation, wherein to detect the noise level on the plurality of electrodes, the noise listening circuit is configured to;

compare the noise level to a first noise threshold; and

detect noise if the noise level exceeds the first noise threshold.

10. The capacitance sensing system of claim 9, wherein the sense network operates at a first operating frequency in the first mode of operation and at a second operating frequency in the second mode of operation, wherein to switch the controller to the second mode of operation, the sense control circuit is configured to select one of a plurality of operating frequencies defined by a frequency hopping algorithm, wherein the second operating frequency is the one of the plurality of operating frequencies with a lowest noise level.

11. The capacitance sensing system of claim 8, wherein the calibration data defines a constant integration time used for one half-period when scanning the electrodes at both the first and second operating frequencies.

12. The capacitance sensing system of claim 8,

the noise listening circuit further configured to detect a high noise level on the plurality of electrodes during the first mode of operation;

and

the sense control circuit further configured to decrease an integration time when scanning the plurality of electrodes during the first mode of operation.

13. The capacitance sensing system of claim 12, wherein to detect a high noise level on the plurality of electrodes, the noise listening circuit is configured to:

comparing a noise level to a second noise threshold; and

detect high noise if the noise level exceeds the second noise threshold.

14. The capacitance sensing system of claim 12, wherein the sense control circuit is further configured to decrease the integration time to a reduced integration time with a specified relationship between the reduced integration time and a length of pauses between integrations.

15. A host device comprising:

a display;

a capacitance sensing array disposed in connection with the display;

a touchscreen controller coupled to the capacitance sensing array, wherein the touchscreen controller comprises;

a capacitance sensing circuit coupled to the capacitance sensing array; and

a noise listening circuit coupled to the capacitance sensing array, wherein the noise listening circuit is configured to detect noise on the capacitance sensing circuit from at least one noise source at a first operating frequencies, wherein the touchscreen controller is configured to switch to a second operating frequency in response to detecting the noise, wherein a constant integration time is used for one half-period when scanning the capacitance sense array at both the first and second operating frequencies.

16. The host device of claim 15, wherein to detect noise on the capacitance sensing array, the noise listening circuit is configured to:

compare a noise level to a first noise threshold; and

detect noise if the noise level exceeds the first noise threshold.

17. The host device of claim 15, wherein to switch to the second operating frequency, the controller is configured to select one of a plurality of operating frequencies defined by a frequency hopping algorithm, wherein the second operating frequency is the one of the plurality of operating frequencies with a lowest noise level.

18. The host device of claim 15, wherein the constant integration time is defined in a single set of configuration data used for both the first and second operating frequencies.

19. The host device of claim 15,

the noise listening circuit further configured to detect a high level of noise on the capacitance sensing circuit at the first operating frequency;

and

the touchscreen controller further configured to decrease the integration time when scanning the capacitance sense array at the first operating frequency.

20. The host device of claim 19, wherein the touchscreen controller is further configured to decrease the integration time to a reduced integration time with a specified relationship between the reduced integration time and a length of pauses between integrations.