Noise measurement in capacitive touch sensors
First Claim
Patent Images
1. An apparatus comprising:
- a drive electrode;
a sense electrode; and
circuitry configured to perform operations comprising;
making, in a noise-measurement phase, a first measurement by performing operations comprising;
providing a pre-determined amount of charge to a charge-measurement capacitor;
transferring a first amount of charge on the sense electrode to the charge-measurement capacitor, thereby modulating the first amount of charge by the pre-determined amount of charge provided to the charge-measurement capacitor; and
measuring a first voltage of the charge-measurement capacitor to determine the first amount of charge; and
making, in a proximity-detection phase, a second measurement by performing operations comprising;
providing a drive signal to the drive electrode;
transferring a second amount of charge on the sense electrode to the charge-measurement capacitor; and
measuring a second voltage of the charge-measurement capacitor to determine the second amount of charge.
13 Assignments
0 Petitions
Accused Products
Abstract
In certain embodiments, an apparatus comprises a charge-measurement capacitor and circuitry. The circuitry is configured to provide a pre-determined amount of charge to the charge-measurement capacitor and transfer an accumulated amount of charge on a sense electrode to the charge-measurement capacitor, the accumulated amount of charge having accumulated on the sense electrode due at least in part to noise. The circuitry is configured measure a voltage of the charge-measurement capacitor to determine the accumulated amount of charge.
-
Citations
17 Claims
-
1. An apparatus comprising:
-
a drive electrode; a sense electrode; and circuitry configured to perform operations comprising; making, in a noise-measurement phase, a first measurement by performing operations comprising; providing a pre-determined amount of charge to a charge-measurement capacitor; transferring a first amount of charge on the sense electrode to the charge-measurement capacitor, thereby modulating the first amount of charge by the pre-determined amount of charge provided to the charge-measurement capacitor; and measuring a first voltage of the charge-measurement capacitor to determine the first amount of charge; and making, in a proximity-detection phase, a second measurement by performing operations comprising; providing a drive signal to the drive electrode; transferring a second amount of charge on the sense electrode to the charge-measurement capacitor; and measuring a second voltage of the charge-measurement capacitor to determine the second amount of charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An apparatus comprising:
-
a charge-measurement capacitor; and circuitry configured to perform operations comprising; providing a pre-determined amount of charge to the charge-measurement capacitor; transferring an accumulated amount of charge on a sense electrode to the charge-measurement capacitor, the accumulated amount of charge having accumulated on the sense electrode due at least in part to noise; measuring a voltage of the charge-measurement capacitor to determine the accumulated amount of charge; and calculating a noise factor to configure a filter based on the accumulated amount of charge. - View Dependent Claims (10, 11, 12)
-
-
13. Circuitry comprising logic embodied in a non-transitory computer-readable medium, the logic when executed configured to perform operations comprising:
-
providing a first control signal to cause a voltage to be applied, providing a pre-determined amount of charge to a charge-measurement capacitor; providing a second control signal to cause an accumulated amount of charge on a sense electrode to be transferred to the charge-measurement capacitor, thereby modulating the accumulated amount of charge by the pre-determined amount of charge provided to the charge-measurement capacitor, the accumulated amount of charge having accumulated on the sense electrode due at least in part to noise; and providing a third control signal to cause a voltage of the charge-measurement capacitor to be measured to determine the accumulated amount of charge. - View Dependent Claims (14, 15, 16, 17)
-
Specification