HIGH SPEED, LOW POWER HIGH COMMON MODE RANGE VOLTAGE MODE DIFFERENTIAL DRIVER CIRCUIT

摘要

A BICMOS OUTPUT DRIVER FOR A TRANSCEIVER CIRCUIT HAS A PULL-UP/PULL-DOWN CIRCUIT (14, 17) WITH CMOS TRANSISTORS SUPPLYING BASE CURRENT TO BIPOLAR PULL-UP/PULL-DOWN TRANSISTORS. IN ITS QUIESCENT STATE, THE CMOS TRANSISTORS DRAW NO CURRENT. A CURRENT MIRROR CIRCUIT COMPRISING A PAIR OF BIPOLAR TRANSISTORS SIZED TO BE A FRACTION OF THE PULL-UP/PULL-DOWN TRANSISTORS IS COUPLED BETWEEN THE INPUT AND OUTPUT OF THE PULL-UP/PULL-DOWN CIRCUIT (14, 17) TO PREVENT EXCEEDING A PREDETERMINED CURRENT. A SPEED UP CIRCUIT (16, 19) COMPRISING CMOS TRANSISTORS IS COUPLED BETWEEN GROUND AND THE BASE OF THE BIPOLAR PULL-UP/PULL-DOWN TRANSISTORS TO SPEED UP THE SHUT OFF OF THE TRANSISTORS. (FIG. 3)