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. 18, 1997
Filed:
Nov. 18, 1994
Petrus H Seesink, NL-5627 KE Eindhoven, NL;
Georg Schneider, D-79650 Schopfheim, NL;
Richard Wagner, D-79618 Rheinfelden, NL;
Vierten M Mellert, D-77790 Steinach, NL;
Other;
Abstract
A circuit arrangement for the linearization and temperature compensation of capacitive sensor signals is provided which requires few components and wherein the compensated input signal is obtained fast. The arrangement includes: a clock generator; a reference capacitor; a measuring capacitor; a temperature-dependent voltage divider connected between an operating and a reference potential which measures the temperature of the measuring capacitor; an adjusting circuit which acts on the measuring capacitor and the reference capacitor and having a first input connected to the operating potential, a second input connected to the voltage divider, and a third input; an integrating stage connected to the measuring capacitor and the reference capacitor and having its output coupled to the third input of the adjusting circuit, the output being the output of the arrangement. The output signal is ##EQU1## where C.sub.v =(C.sub.m -C.sub.r)/C.sub.m, (C.sub.m -C.sub.r)/(C.sub.m +C.sub.r) , or (C.sub.m -C.sub.r)/C.sub.r ; C.sub.m is the capacitance of the capacitor; C.sub.r is the capacitance of the reference capacitor; U is the operating potential; a.sub.0 is a zero adjustment value; a.sub.1 is a temperature coefficient zero adjustment value; a.sub.2 is a first span adjustment value; a.sub.3 is a temperature coefficient span adjustment value; b.sub.0 is a second span adjustment value; b.sub.1 is a linearization adjustment value, and v.sub.1 is the temperature-dependent resistance ratio of the voltage divider.