Programmable impedance transmitter for serial communication

摘要

Embodiments include apparatuses, methods, and systems for transmitting a data signal over one or more transmission lines. In one embodiment, a transmitter circuit includes a plurality of programmable impedance driver (PID) circuits coupled in parallel with one another to drive a data signal on a transmission line. The individual PID circuits may include a pull-up transistor to receive a pull-up signal, a pull-down transistor to receive a pull-down signal, and first and second resistors coupled in series with one another between the pull-up and pull-down transistors. An output contact may be coupled to a node between the first and second resistors to pass an output signal that is responsive to the pull-up and pull-down signals. The individual PID circuits may further include a switch transistor coupled in parallel with the first and second resistors, and a control contact coupled to the switch transistor to receive a control signal to switch the switch transistor on or off to control an impedance at the output contact.

主权项

1. A circuit comprising:
a plurality of programmable impedance driver (PID) circuits coupled in parallel with a same output terminal to drive a transmission signal on a transmission line coupled to the output terminal, wherein individual PID circuits of the plurality of PID circuits include:
a pull-up transistor to receive a pull-up signal at a gate terminal of the pull-up transistor;a pull-down transistor to receive a pull-down signal at a gate terminal of the pull-down transistor;first and second resistors coupled in series with one another between the pull-up and pull-down transistors;an output contact coupled between the output terminal and a node between the first and second resistors to pass an output signal to the output terminal that is responsive to the pull-up and pull-down signals;a switch transistor coupled in parallel with the first and second resistors; anda control contact coupled to a gate terminal of the switch transistor to receive a control signal to switch the switch transistor on or off to control an impedance at the output contact.