Patent ID: 7330056
Filing Date: 2008-02-12
Classification: H04L

Abstract:
1. An output driver comprising: a voltage-controlled resistor; a voltage-controlled current sink; and a switching stage disposed between the voltage-controlled resistor and the voltage-controlled current sink and adapted to generate an output voltage across an external load said output voltage to vary between first and second output voltages, wherein the resistance of said voltage-controlled resistor is controlled by a first operational amplifier and the current through the voltage-controlled current sink is controlled by a second operational amplifier wherein said switching stage further comprises: a first resistor having a first terminal coupled to a first terminal directly of the voltage-controlled resistor and a second terminal directly coupled to a first output node; a first transistor having a first terminal coupled to the first output node, a second terminal coupled to a first terminal of the voltage-controlled current sink, and a third terminal coupled to a first input voltage; a second transistor having a first terminal coupled to a second output node, a second terminal coupled to the first terminal of the voltage-controlled current sink, and a third terminal coupled to a second input voltage; and a third transistor having a first terminal coupled to the first terminal of the voltage-controlled resistor, a second terminal coupled to the second output node, and a third terminal coupled to the second input voltage.