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:
Apr. 28, 1998
Filed:
May. 30, 1995
Yoshimi Asada, Kawasaki, JP;
Tatsumi Nakada, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
When a selector selects a first input terminal, a first loop circuit is formed including first and second input buffer circuits and an output buffer circuit. When the selector selects a second input terminal, a second loop circuit is formed including the first input buffer circuit and the output buffer circuit. When the selector selects a third input terminal, a third loop circuit is formed including the first input buffer circuit, a variable delay line (VDL), and the output buffer circuit. From the oscillating frequencies of loop circuits each formed as a ring oscillator, their respective signal delay times are obtained. By equalizing characteristics of first and second input buffer circuits, through a mutual operation using the signal delay times of respective loop circuits, a propagation delay time over a timing signal supply path including the first input buffer circuit and the VDL and stretching to a flip-flop is obtained precisely.