Patent ID: 8816726
Filing Date: 2014-08-26
Classification: H03K,H04L

Abstract:
1. A differential signaling driver, comprising: a current source, connected between an operation voltage and a first node, and supplying a driving current to the first node; a differential signal generator, connected between the first node and a second node, receiving a digital input signal, and generating a pair of differential output signals at a first output node and a second output node according to the digital input signal; and a first resistor, connected between the second node and a ground voltage, wherein the differential signal generator couples the first output node to the operation voltage and the second output node to the ground voltage or couples the first output node to the ground voltage and the second output node to the operation voltage according to the digital input signal; wherein the first resistor is implemented with an RTN (Resistor Tuning Network) element comprising: a plurality of tunable branches, coupled in parallel between a first terminal and a second terminal of the RTN element, wherein each of the tunable branches comprises a resistor and a transistor, and the transistors each have a control terminal to selectively activate the transistor; and a comparator, comparing a reference voltage difference with a voltage difference between the first terminal and the second terminal, and outputting a comparison signal according to the reference voltage difference and the voltage difference between the first terminal and the second terminal, wherein the control terminals of the transistors of the plurality of tunable branches are coupled to the comparison signal.