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. 05, 2008
Filed:
Jul. 26, 2006
Tsukasa Fujimori, Kokubunji, JP;
Natsuki Yokoyama, Mitaka, JP;
Hiroshi Fukuda, Tokyo, JP;
Yuko Hanaoka, Kodaira, JP;
Takashi Azuma, Kawasaki, JP;
Tsukasa Fujimori, Kokubunji, JP;
Natsuki Yokoyama, Mitaka, JP;
Hiroshi Fukuda, Tokyo, JP;
Yuko Hanaoka, Kodaira, JP;
Takashi Azuma, Kawasaki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A sensor and sensor module with small power consumption and high reliability are disclosed. The sensor includes a capacitor having a capacitance varying with a physical quantity, a capacitance-voltage conversion circuit for converting the capacitance of the capacitor into a voltage, and a control signal generation circuit for generating a plurality of control signals. The capacitor has a frequency-capacitance characteristic with a resonant frequency. In a measurement of the physical quantity, the capacitance of the capacitor is measured with one of the control signals having a first frequency which is much higher or much lower than the resonant frequency. In a self-diagnosis of the sensor, the capacitance of the capacitor is measured with another one of the control signals having a second frequency which is equal or close to the resonant frequency.