LVDS output driver having low supply voltage capability

An apparatus, comprising:

• a plurality of source followers, each of the plurality of source followers comprising a pull-down transistor having a source, a drain, a gate, and a bulk terminal;
• a plurality of pull-up transistors, each of the plurality of pull-up transistors m having a source, a drain, and a gate, wherein the drain of each of the plurality of the pull-up transistors is coupled to the source of a pull-down transistor of the plurality of source followers, to output a plurality of differential signals via the drains of the plurality of pull-up transistors;
• a first current source coupled to the sources of the plurality of pull-up transistors;
• an operational amplifier, coupled to the first current source, to drive the first current source;
• and
• a feedback path coupled between the drains of the plurality of pull-up;
• transistors and an input of the operational amplifier, wherein the feedback path further comprises a sensing circuit, the sensing circuit includes a plurality of transistors biased by a predetermined voltage.

An apparatus, comprising:

• a plurality of source followers, each of the plurality of source followers comprising a pull-down transistor having a source, a drain, a gate, and a bulk terminal;
• a plurality of pull-up transistors, each of the plurality of pull-up transistors CD having a source, a drain, and a gate, wherein the drain of each of the plurality of pull-up transistors is coupled to the source of a pull-down transistor of the plurality of source followers, to output a plurality of differential signals via the drains of the plurality of pull-up transistors;
• a low swing differential pre-driver, coupled to the gates of the pull-down m transistors of the plurality of source followers, to drive the pull-down transistors;
• and
• a plurality of inverters, each of the plurality of inverters being coupled to the gate of each of the plurality of pull-up transistors to amplify an input signal and to apply the amplified signal to the gate of the corresponding pull-up transistor, wherein the plurality of inverters are powered by a second voltage approximately between 1.1V and 1.3V.

A method comprising:

• providing a plurality of input signals to a plurality of pull-up transistors;
• coupling each of the plurality of pull-up transistors to one of a plurality of pull-down transistors;
• driving the plurality of pull-down transistors with a plurality of differential low swing signals to output a plurality of low voltage differential signals in response to the plurality of input signals;
• and
• generating the plurality of differential low swing signals using a low swing differential pre-driver, wherein generating the plurality of differential low swing signals using the low swing differential pre-driver comprises:
• supplying current to a load from a second current source;
• sinking the current from the load via a transistor and a resistor, the transistor being coupled to the resistor in parallel;
• and
• outputting a plurality of low swing differential signals via the load to the gates of the plurality of pull-down transistors.

A method, comprising

• providing a plurality of input signals to a plurality of pull-up transistors,
• coupling each of the plurality of pull-up transistors to one of a plurality of pull-down transistors;
• driving the plurality of pull-down transistors with a plurality of differential low swing signals to output a plurality of low voltage differential signals in response to the plurality of input signals;
• amplifying the plurality of input voltages using a plurality of inverters, each of the plurality of inverters being coupled to a distinct one of the plurality of pull-up transistors;
• and
• powering the plurality of inverters by a voltage approximately between 1.1V and 1.3V.

An apparatus comprising:

• means for providing a plurality of input signals to a plurality of pull-up transistors;
• means for coupling each of the plurality of pull-up transistors to one of a plurality of pull-down transistors;
• means for driving the plurality of pull-down transistors with a plurality of differential low swing signals to output a plurality of low voltage differential signals in response to the plurality of input signals;
• means for generating the plurality of differential low swing signals using a low swing differential pre-driver, wherein the means for generating the plurality of differential low swing signals using the low swing differential pre-driver comprises:
• means for supplying current to a load from a second current source;
• means for sinking the current from the load via a transistor and a resistor, the transistor being coupled to the resistor in parallel;
• and In
• means for outputting a plurality of low swing differential signals via H the load to the gates of the plurality of pull-down transistors.