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:
Jan. 02, 2018
Filed:
May. 23, 2013
Hitachi, Ltd., Chiyoda-ku, Tokyo, JP;
Toshiyuki Usagawa, Tokyo, JP;
HITACHI, LTD., Tokyo, JP;
Abstract
A semiconductor gas sensor includes a CMOS inverter which is configured by an n-channel field effect transistor having a catalytic gate and a p-channel field effect transistor having the catalytic gate. An input setting gate potential Vin(D) of the CMOS inverter is set to satisfy 'Vin(D)=Vtc−ΔVgth' by using the sensor response threshold intensity ΔVgth determined by a concentration of a gas to be detected and a threshold input potential Vtc of the CMOS inverter. Therefore, only by setting the input setting gate potential Vin(D), a warning or an alarm can be issued for the concentration of the gas to be detected. In addition, a temperature compensation of the threshold voltage caused by a MOS structure is reduced regardless of the detection gas by setting a characteristic coefficient β, a threshold voltage Vtn of the n-channel field effect transistor, and the threshold voltage Vtp of the p-channel field effect transistor so as to satisfy relations 'β=1' and “Vtp=−Vtn”.