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:
Mar. 22, 2016
Filed:
Nov. 19, 2013
Applicant:
Hitachi, Ltd., Tokyo, JP;
Inventors:
Yasuyoshi Sunaga, Tokyo, JP;
Hideki Sakakibara, Tachikawa, JP;
Yuko Ito, Akishima, JP;
Tomoji Nakamura, Fussa, JP;
Atsushi Hazeyama, Ome, JP;
Kozaburo Kurita, Ome, JP;
Koki Tsutsumida, Ome, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 29/00 (2006.01); G01R 31/30 (2006.01); G01R 19/00 (2006.01); G01R 21/00 (2006.01);
U.S. Cl.
CPC ...
G01R 31/3016 (2013.01); G01R 19/0084 (2013.01); G01R 19/0092 (2013.01); G01R 21/00 (2013.01);
Abstract
There is provided a semiconductor integrated circuit in which a ring oscillator is formed by a variable delay circuit to cause the ring oscillator to oscillate (S) at the test operation of the variable delay circuit and it is determined whether the variable delay circuit is normal or abnormal depending on whether the ring oscillator satisfies a predetermined monotonic increase condition (S) and a predetermined linearity condition (S).