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. 27, 1999
Filed:
Jan. 24, 1997
Peter Ruetz, Redwood City, CA (US);
Synopsys, Inc., Mountain View, CA (US);
Abstract
The hybrid adder of the present invention uses stages of carry select functions to provide serial carries and a carry look-ahead tree structure to compute the final carries in parallel. The longer the carry select stages become, the slower and smaller the hybrid adder gets by reducing the size of the carry tree. By making the carry select stages shorter, the faster and larger the adder gets by increasing the size of the carry tree. The increased flexibility of the resulting hybrid adder gives the circuit designer a greater range of possible designs to achieve optimum size and speed performance. A preferred process for selecting optimum stage lengths is also described. The method for designing the hybrid adder is preferably carried out using a logic synthesis software program.