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:
Sep. 13, 1994
Filed:
Mar. 30, 1993
Izumi Sakai, Yokohama, JP;
Yukinori Uchino, Yokohama, JP;
Yasunori Tanaka, Yokosuka, JP;
Toshiaki Mori, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In an integrated circuit device using a plurality of different power supply voltages, the application of an input voltage exceeding the power supply voltages to an input/output circuit is prevented. When a p-type substrate is used, a plurality n-wells are formed to surround an integrated circuit region on a central portion of the substrate. When an n-type substrate is used, a plurality of p-wells are formed in the same manner. A predetermined power supply voltage is applied to each well to select transistors of the input/output buffer in accordance with the voltage level of an external voltage.