Ultra-high-speed PAM-N CMOS inverter serial link
AssigneeXilinx, Inc.
InventorsRonan Sean Casey, Lokesh Rajendran, Declan Carey, Kevin Zheng, Catherine Hearne, Hongtao Zhang
Life of this patent
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Abstract
Methods, systems, and apparatus described herein make a multi-level PAM signal (PAM-N signal) at a transmitter using CMOS-based components. By forming the PAM-N signal at the transmitter, receivers do not have to recombine and/or realign multiple signals and only employs a single transmission line channel (or two transmission line channels in differential implementations) to convey the data stream to the receiver from the transmitter.
Claims21
A transmitter circuit comprising:
- two or more input converter circuits coupled in parallel, each of the two or more input converter circuits configured to convert a non-return-to-zero (NRZ) input voltage signal to a corresponding current signal;
- and
- a combining circuit, the combining circuit configured to combine the two or more corresponding current signals to generate a pulse amplitude modulation level N (PAM-N) signal output,
- wherein the two or more input converter circuits and the combining circuit comprise a CMOS-inverter-based circuit.
A method of transmitting data signals, the method comprising:
- receiving a plurality of non-return to zero (NRZ) input voltage signals at a plurality of parallel coupled corresponding input converter circuits;
- generating a plurality of current signals based on converting each of the plurality of NRZ input voltage signals into corresponding current signals via the plurality of parallel coupled corresponding input converter circuits;
- and
- generating an output multilevel pulse amplitude modulation (PAM-N) voltage signal based on the plurality of current signals,
- wherein the plurality of parallel coupled corresponding input converter circuits comprise CMOS-inverter-based circuits.
A data link circuit comprising:
- a transmitter circuit configured to:
- receive a plurality of input non-return-to-zero (NRZ) voltage signals;
- convert the input NRZ voltage signals into a plurality of corresponding current signals via CMOS-inverter-based circuits;
- and
- generate a PAM-N signal as an output voltage signal based on the plurality of current signals;
- a receiver circuit configured to:
- receive the PAM-N signal from the transmitter circuit;
- and
- a transmission line or channel configured to convey the PAM-N signal from the transmitter circuit to the receiver circuit.
A transmitter circuit comprising:
- two or more input converter circuits coupled in parallel, each of the two or more input converter circuits configured to convert a non-return-to-zero (NRZ) input voltage signal to a corresponding current signal;
- and
- a combining circuit, the combining circuit configured to combine the two or more corresponding current signals to generate a pulse amplitude modulation level N (PAM-N) signal output,
- wherein each of the two or more input converter circuits or the combining circuit are hardcoded or programmed with a respective weight, and wherein the respective weights for the two or more input converter circuits are programmed to reduce a number of levels in the PAM-N signal output based on tristating at least one of the two or more input converter circuits or making the NRZ input voltage signal of a plurality of the two or more input converter circuits identical.
Dependencies are inferred from the claim text.