The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 23, 2010
Filed:
Jul. 24, 2007
Erik Anderson, Shoreline, WA (US);
Erik Anderson, Shoreline, WA (US);
Cypress Semiconductor Corporation, San Jose, CA (US);
Abstract
A capacitive sensor with ratiometric voltage references includes a voltage source, a charge transfer switch, an integrating capacitor, and a comparator. The voltage source is configured to generate a first voltage reference and a second voltage reference in response to a supply voltage, where the first voltage reference changes proportionally to the second voltage reference in response to a change in the supply voltage. The charge transfer switch is coupled to the integrating capacitor to distribute charge between a sensing capacitor and the integrating capacitor, where the charge is accumulated in response to the first voltage reference. The comparator is coupled to the second voltage reference and the integrating capacitor to compare a voltage on the integrating capacitor against the second voltage reference.