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:
Dec. 07, 2021
Filed:
Oct. 12, 2020
Rambus Inc., San Jose, CA (US);
Kamran Farzan, Toronto, CA;
Aaron Ali, Holland Landing, CA;
Rambus Inc., San Jose, CA (US);
Abstract
A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.