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:
Jan. 22, 1985
Filed:
Jun. 17, 1982
John J Zasio, Sunnyvale, CA (US);
Storage Technology Partners, Louisville, CO (US);
Abstract
A CMOS LSI or VLSI integrated circuit chip includes a shift register circuit that provides internal delay testing capability. The shift register circuit is disposed around the periphery of the chip and includes a large number of serially connected stages. One mode of operation allows a data signal to pass through the shift register circuit at a speed limited only by the propagation delays associated with the individual stages thereof. In this mode of operation, one net inversion is introduced into the data path and the output of a final stage of the shift register circuit is coupled to the input of a first stage of the shift register circuit, thereby creating a ring oscillator. The period of oscillation of this ring oscillator represents a measure of the average propagation delay times associated with the various circuit elements employed within the LSI or VLSI circuitry. Such delay measurements can readily be made at any level of packaging or system operation.