Capacitive sensing
First Claim
1. A multi-channel capacitive sensor comprising:
- a sample capacitor coupled to a first sense electrode and to a second sense electrode, the first sense electrode associated with a first sense capacitor and a first diode and the second sense electrode associated with a second sense capacitor and a second diode, the first sense capacitor being distinct from the second sense capacitor, the sample capacitor configured for use in measuring a capacitance of the first sense capacitor and in measuring a capacitance of the second sense capacitor; and
a control circuit programmed to;
apply, at a first time via a drive channel, a first drive signal to the sample capacitor;
apply, while allowing the first drive signal received from the sample capacitor to be conducted by the first diode to the first sense electrode associated with the first sense capacitor, a first signal to the second sense capacitor to prevent the first drive signal from being conducted by the second diode to the second sense electrode associated with the second sense capacitor;
apply, at a second time via the drive channel, a second drive signal to the sample capacitor of the multi-channel capacitive sensor; and
apply, while allowing the second drive signal received from the sample capacitor to be conducted by the second diode to the second sense electrode associated with the second sense capacitor, a second signal to the first sense capacitor to prevent the second drive signal from being conducted by the first diode to the first sense electrode associated with the first sense capacitor.
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Accused Products
Abstract
A multi-channel capacitive sensor comprises a sample capacitor having first and second terminals, a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. The sample capacitor and diodes are coupled to a control circuit. The control circuit is operable to apply a drive signal to the first terminal of the sample capacitor while simultaneously applying a bias signal to the second terminal of one or other of the diodes to prevent the diode from conducting the drive signal.
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Citations
20 Claims
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1. A multi-channel capacitive sensor comprising:
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a sample capacitor coupled to a first sense electrode and to a second sense electrode, the first sense electrode associated with a first sense capacitor and a first diode and the second sense electrode associated with a second sense capacitor and a second diode, the first sense capacitor being distinct from the second sense capacitor, the sample capacitor configured for use in measuring a capacitance of the first sense capacitor and in measuring a capacitance of the second sense capacitor; and a control circuit programmed to; apply, at a first time via a drive channel, a first drive signal to the sample capacitor; apply, while allowing the first drive signal received from the sample capacitor to be conducted by the first diode to the first sense electrode associated with the first sense capacitor, a first signal to the second sense capacitor to prevent the first drive signal from being conducted by the second diode to the second sense electrode associated with the second sense capacitor; apply, at a second time via the drive channel, a second drive signal to the sample capacitor of the multi-channel capacitive sensor; and apply, while allowing the second drive signal received from the sample capacitor to be conducted by the second diode to the second sense electrode associated with the second sense capacitor, a second signal to the first sense capacitor to prevent the second drive signal from being conducted by the first diode to the first sense electrode associated with the first sense capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A device comprising:
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one or more processors; and one or more memory units coupled to the one or more processors, the one or more memory units collectively storing logic configured to, when executed by the one or more processors, cause the one or more processors to perform operations comprising; applying, at a first time via a drive channel, a first drive signal to a sample capacitor of a multi-channel capacitive sensor, the sample capacitor coupled to a first sense electrode and to a second sense electrode, the first sense electrode associated with a first sense capacitor and a first diode and the second sense electrode associated with a second sense capacitor and a second diode, the first sense capacitor being distinct from the second sense capacitor, the sample capacitor configured for use in measuring a capacitance of the first sense capacitor and in measuring a capacitance of the second sense capacitor; applying, while allowing the first drive signal received from the sample capacitor to be conducted by the first diode to the first sense electrode associated with the first sense capacitor, a first signal to the second sense capacitor to prevent the first drive signal from being conducted by the second diode to the second sense electrode associated with the second sense capacitor; applying, at a second time via the drive channel, a second drive signal to the sample capacitor of the multi-channel capacitive sensor; and applying, while allowing the second drive signal received from the sample capacitor to be conducted by the second diode to the second sense electrode associated with the second sense capacitor, a second signal to the first sense capacitor to prevent the second drive signal from being conducted by the first diode to the first sense electrode associated with the first sense capacitor. - View Dependent Claims (17, 18)
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19. A method comprising:
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applying, at a first time via a drive channel, a first drive signal to a sample capacitor of a multi-channel capacitive sensor, the sample capacitor coupled to a first sense electrode and to a second sense electrode, the first sense electrode associated with a first sense capacitor and a first diode and the second sense electrode associated with a second sense capacitor and a second diode, the first sense capacitor being distinct from the second sense capacitor, the sample capacitor configured for use in measuring a capacitance of the first sense capacitor and in measuring a capacitance of the second sense capacitor; applying, while allowing the first drive signal received from the sample capacitor to be conducted by the first diode to the first sense electrode associated with the first sense capacitor, a first signal to the second sense capacitor to prevent the first drive signal from being conducted by the second diode to the second sense electrode associated with the second sense capacitor; applying, at a second time via the drive channel, a second drive signal to the sample capacitor of the multi-channel capacitive sensor; and applying, while allowing the second drive signal received from the sample capacitor to be conducted by the second diode to the second sense electrode associated with the second sense capacitor, a second signal to the first sense capacitor to prevent the second drive signal from being conducted by the first diode to the first sense electrode associated with the first sense capacitor. - View Dependent Claims (20)
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Specification