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. 25, 2014
Filed:
May. 16, 2011
Toshiyuki Suzuki, Kiyosu, JP;
Toshiyuki Suzuki, Kiyosu, JP;
Denso Corporation, Kariya, JP;
Abstract
In a sensor control circuit, an impedance signal output unit has a HPF, a P/H circuit, a LPF, etc., and detects an element impedance of a sensor element on the basis of an impedance response signal which is alternately changed in response to an alternating current signal supplied to the sensor element. The P/H circuit has an input comparator which inputs an impedance detection voltage Vz after the HPF, a rectifying element connected to the P/H circuit, and a hold capacitor which is charged by the output of the input comparator. The input comparator has a constant current circuit and a transistor. The constant current circuit limits an updating value of a hold voltage value Vph of the hold capacitor every alternating current period. The sensor control device detects the element impedance of the sensor element with high accuracy while preventing influence of noise.