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:
Apr. 01, 2014
Filed:
Jul. 20, 2010
Andrew Marshall, Dallas, TX (US);
Md. Imran Hossain, Plano, TX (US);
Michelle N. Nguyen, Rowlett, TX (US);
Andrew Marshall, Dallas, TX (US);
Md. Imran Hossain, Plano, TX (US);
Michelle N. Nguyen, Rowlett, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Circuitry and methods for measuring capacitive mismatch with improved precision. The capacitors under measurement are connected in series in a voltage divider, with the node common to both capacitors connected to the gate of a source follower transistor. In one disclosed embodiment of the invention, a ramped voltage is applied to the drain of the source follower transistor simultaneously with the ramped voltage applied to the voltage divider; the slope of the ramped drain voltage is at the nominal slope of the voltage at the common node of the voltage divider. In another embodiment, a second transistor in saturation has its gate coupled to the source of the source follower device, and its source connected to the drain of the source follower device in series with a constant voltage drop. The drain-to-source voltage of the source follower device is thus held constant in each embodiment, improving precision of the measurement.