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:
Jun. 29, 1999
Filed:
Apr. 22, 1997
Applicant:
Inventor:
David B Rees, Overton Hants, GB;
Assignee:
Cypress Semiconductor Corp., San Jose, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ; H03K / ;
U.S. Cl.
CPC ...
326 27 ; 326 83 ; 326 86 ; 326 30 ;
Abstract
The present invention concerns an output buffer, which overcomes previous disadvantages of driving transmission line loads by providing a variable output impedance in response to the load on the output. The buffer generally comprises a pullup device for providing a high voltage at the output in response to a first input, a pulldown device configured to provide a low voltage at the output in response to a second input and a second pulldown device configured to provide additional low drive at the output. The second pulldown device provides an impedance at the output which varies with respect to the voltage present at the output.