US Patent No. 10,599,606

424 ENCODING SCHEMES TO REDUCE COUPLING AND POWER NOISE ON PAM-4 DATA BUSES


Patent No. 10,599,606
Issue Date March 24, 2020
Title 424 Encoding Schemes To Reduce Coupling And Power Noise On Pam-4 Data Buses
Inventorship Donghyuk Lee, Cedar Park, TX (US)
John Wilson, Wake Forest, NC (US)
Assignee NVIDIA Corp., Santa Clara, CA (US)

Claim of US Patent No. 10,599,606

1. A method of encoding a series of data bits onto a serial data bus, the method comprising:determining if (a) a first four-level symbol for a first sequence of two bits of the series of data bits is at a first voltage level of a Pulse Amplitude Modulation 4 Level (PAM-4) encoding, wherein the first voltage level is one of a highest of four voltage levels of the PAM-4 encoding and a lowest of the four voltage levels of the PAM-4 encoding;
determining if (b) a second four-level symbol for a second sequence of two bits of the series of data bits immediately following the first sequence of two bits is at a second voltage level of the PAM-4 encoding different than the first voltage level, wherein the second voltage level is one of the highest voltage level used by the PAM-4 encoding and the lowest voltage level used by the PAM-4 encoding; and
on condition that (a) and (b) are both true, encoding a two-level bridge symbol between the first four-level symbol and the second four-level symbol on a data lane of the serial data bus.