Patent ID: 6331786
Filing Date: 2001-12-18
Classification: H04L

Abstract:
A active termination circuit for terminating a signal traversing on a transmission line having a selective DC power consumption, comprising:a first clamping transistor coupled to a first potential having a first clamping transistor control node arranged for clamping said signal at about a first reference voltage;a first threshold reference transistor coupled to a first reference voltage supply configured to supply a first reference voltage, wherein the first threshold reference transistor provides a first bias voltage to said first clamping transistor control node that biases said first clamping transistor control node at about a first threshold voltage from said first reference voltage, said first threshold voltage representing a threshold voltage of said first clamping transistor;a second clamping transistor coupled to a second potential having a second clamping transistor control node arranged for clamping said signal at about a second reference voltage; anda second threshold reference transistor coupled to a second reference voltage supply configured to supply a second reference voltage, wherein said second threshold reference transistor provides a second bias voltage to said second clamping transistor control node that biases said second clamping transistor control node at about a second threshold voltage from said second reference voltage, said second threshold voltage representing a second clamping transistor threshold voltage; anda variable current supply coupled to said first threshold reference transistor and said second threshold reference transistor arranged to reduce the DC power consumption of the active termination circuit as needed.