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. 22, 2011
Filed:
Mar. 06, 2008
Takahisa Hiraide, Kawasaki, JP;
Tatsuru Matsuo, Kawasaki, JP;
Takahisa Hiraide, Kawasaki, JP;
Tatsuru Matsuo, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In a linear feedback shift register (LFSR), a four-bit shift register mainly using F/Fs is formed and an XOR circuit that feeds back an exclusive OR of a first bit and a last bit to the first bit is also provided, thereby outputting a test pattern having a maximum cycle of 15. A phase change circuit that can perform arbitrary phase change of a test pattern based on input of a control signal having a maximum clock number 4 and an average clock number log4 is also formed in the LFSR. As a result, a smaller clock count is required for the LFSR to output a test pattern that matches a test pattern automatically generated by an ATPG.