Capacitive sensing
First Claim
1. A multi-channel capacitive sensor comprising:
- a sample capacitor having a first terminal and a second terminal;
a first diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a first sense electrode;
a second diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a second sense electrode; and
a control circuit operable to;
apply a drive signal to the first terminal of the sample capacitor; and
apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes.
13 Assignments
0 Petitions
Accused Products
Abstract
In certain embodiments, a multi-channel capacitive sensor for measuring capacitances of sense electrodes to a system reference potential comprises a sample capacitor having first and second terminals. The sensor comprises 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 comprises 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. A control circuit is operable to apply a drive signal to the first terminal of the sample capacitor and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes.
-
Citations
20 Claims
-
1. A multi-channel capacitive sensor comprising:
-
a sample capacitor having a first terminal and a second terminal; a first diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a first sense electrode; a second diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a second sense electrode; and a control circuit operable to; apply a drive signal to the first terminal of the sample capacitor; and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A device comprising:
a multi-channel capacitive sensor for measuring the capacitances of a plurality of sense electrodes to a system reference potential, the sensor comprising; a sample capacitor having a first terminal and a second terminal; a first diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a first sense electrode; a second diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a second sense electrode; and a control circuit operable to; apply a drive signal to the first terminal of the sample capacitor; and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes. - View Dependent Claims (18)
-
19. A method comprising:
-
applying a drive signal to a first terminal of a sample capacitor of a multi-channel capacitive sensor, comprising; the sample capacitor having the first terminal and a second terminal; a first diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a first sense electrode; and a second diode having a first terminal directly connected to the second terminal of the sample capacitor and a second terminal directly connected to a second sense electrode; and applying a bias signal to the respective second terminal of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes. - View Dependent Claims (20)
-
Specification