Patent ID: 8446169
Filing Date: 2013-05-21
Classification: H03K,H04L

Abstract:
1. An apparatus for impedance adjustment, comprising: a differential driver circuit having an input port, a first output port, a second output port, a first bias node, and a second bias node; a first analog voltage source a second analog voltage source; a reference resistance circuit having a first tap and a second tap; a feedback control circuit coupled to the first output port, the second output port, the first tap, and the second tap; wherein the feedback control circuit is configured to provide a first digital output to the first analog voltage source in response to a first relationship between first voltages at the first output port and the first tap; and wherein the feedback control circuit is further configured to provide a second digital output to the second analog voltage source in response to a second relationship between second voltages at the second output port and the second tap.