Patent ID: 7969181

Claim:
A method for adjusting an impedance of an output driver of an integrated circuit; the method comprises: receiving, by the output driver, a first square wave signal that should be driven by the output driver to provide a second square wave signal; monitoring, by a monitoring circuit included in the integrated circuit, the second square wave signal during an output driver transient period resulting from a first square wave signal transient to provide a monitoring result, wherein the monitoring comprises comparing temporal values of the second signal, during the output driver transient period, to at least one voltage threshold out of a first voltage threshold and a second voltage threshold, wherein the first voltage threshold is above a matched impedance balanced second signal value, wherein the second voltage threshold is below the matched impedance balanced second signal value, and wherein the first and second voltage thresholds are between steady state values of the second signal; wherein the output driver transient period is followed by a second period during which the second signal has a constant voltage, the second period corresponds to twice a signal flight time through a transmission line coupled to the output driver; wherein the second period is followed by a third period during which the first square signal peaks back in a trend opposing that of the first square wave signal transient; determining whether to adjust the impedance of the output driver in response to the monitoring result; and adjusting the impedance of the output driver in response to the determination.