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:
May. 09, 2000
Filed:
Sep. 29, 1997
Philip M Daniell, Kingsclere, GB;
Cypress Semiconductor Corp., , US;
Abstract
An output buffer is provided in which the output impedance of the buffer is set relatively low during an initial portion of an output transition. Subsequently, near the end of the output transition, the output impedance of the buffer is increased to more closely follow the characteristic impedance of a transmission line driven by the buffer. The output impedance is automatically changed when the buffer output voltage crosses a predetermined threshold. The output buffer includes a voltage threshold detection circuit comprising a diode and a transistor, the diode being coupled to the gate of the transistor. When a voltage level of a signal applied to one of the diode and the transistor crosses a predetermined threshold, a switch state of the diode and/or transistor changes to thereby change an output of the voltage detection circuit and trigger the change of output impedance of the output buffer in a reliable and consistent manner.