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. 04, 2003
Filed:
Feb. 27, 2001
Toshihiko Nakano, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a semiconductor integrated circuit, a selector selects a signal FB at the input thereof by giving a proper level to a signal EN. By setting two-phase scan clocks SC , SC of F/F so that F/F are set to the through state, a signal can be passed from F/F to F/F under a through state in the above circuit. Further, there can be fabricated a critical path-ring oscillator which is self-oscillated in the critical path by negatively feeding back the output of F/F to F/F through the signal FB. The logic in the ring is required to be an inverted logic. In a test other than a speed screening test or at the normal operation time, a proper level is given to the signal EN so that the selector is switched to select the input side, thereby cutting a negative feedback path through which the output of F/F is negatively fed back to F/F