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:
May. 01, 2018
Filed:
Jul. 17, 2015
Synaptics Incorporated, San Jose, CA (US);
Farzaneh Shahrokhi, San Jose, CA (US);
Tracy Scott Dattalo, Santa Clara, CA (US);
Joseph Kurth Reynolds, Alviso, CA (US);
Adam Schwartz, Redwood City, CA (US);
Synaptics Incorporated, San Jose, CA (US);
Abstract
A capacitance measurement circuit comprises a differential amplifier with first and second inputs and an output, first and second feedback capacitances, and a reset mechanism. The first input is coupled to a modulated reference voltage and the second input is coupled with a sensor electrode. A first feedback capacitance is coupled between the output and the second input. A second feedback capacitance is coupled between the output and the second input. The reset mechanism resets the first feedback capacitance to a first level of charge and the second feedback capacitance to a second level of charge. During an absolute capacitance measurement phase, the differential amplifier charges the sensor electrode while balancing voltages on the first and second inputs to a voltage level associated with the modulated reference voltage and integrates charge on the sensor electrode to measure capacitance corresponding to a coupling between the sensor electrode and an input object.