Method and apparatus for multi-mode driver

An apparatus comprising:

• an output circuit that is adapted to drive signals according to a first mode and a second mode, the output circuit including at least one input adapted to receive a mode select input, the mode select input capable of selecting between the first mode and the second mode;
• wherein the first mode comprises a current mode logic (CML) signaling operation type and the second mode comprises a low voltage differential signaling (LVDS) operation type;
• and
• wherein the output circuit is further adapted to switch from being capable of driving signals according to the second mode to being capable of driving signals according to the first mode by shorting a resistive element.

An apparatus comprising:

• an output circuit that is adapted to drive signals according to a first mode and a second mode, the output circuit including at least one input adapted to receive a mode select input, the mode select input capable of selecting between the first mode and the second mode;
• wherein the first mode comprises a current mode logic (CML) signaling operation type and the second mode comprises a low voltage differential signaling (LVDS) operation type;
• and
• wherein the CML signaling operation type of the first mode involves maintaining a predetermined output impedance using an alternating current (AC) ground that is capable of being created at a node between a resistive element and a capacitive element that are connected in series, with the capacitive element coupled to a ground potential.

An apparatus comprising:

• a differential amplifier pair including first and second transistors and first and second loading resistive elements;
• the first transistor connected in series with the first loading resistive element and the second transistor connected in series with the second loading resistive element, the first transistor and the first loading resistive element connected in parallel with the second transistor and the second loading resistive element at an upper node and a lower node;
• a first output driver input located at a gate terminal of the first transistor;
• a second output driver input located at a gate terminal of the second transistor;
• a first output driver output node located between the first transistor and the first loading resistive element;
• a second output driver output node located between the second transistor and the second loading resistive element;
• a resistive element coupled to the upper node;
• and
• a switch having an open position and a closed position, the switch coupled to the upper node and connected in parallel with the resistive element, the switch capable of shorting the resistive element when in the closed position;
• wherein a first output driver mode is enabled when the switch is in the closed position and a second output driver mode is enabled when the switch is in the open position.

An apparatus comprising:

• a differential amplifier pair including first and second transistors and first and second loading resistive elements;
• the first transistor connected in series with the first loading resistive element and the second transistor connected in series with the second loading resistive element, the first transistor and the first loading resistive element connected in parallel with the second transistor and the second loading resistive element at an upper node and a lower node;
• a first output driver input located at a gate terminal of the first transistor;
• a second output driver input located at a gate terminal of the second transistor;
• a first output driver output node located between the first transistor and the first loading resistive element;
• a second output driver output node located between the second transistor and the second loading resistive element;
• a resistive element coupled to the upper node;
• and
• a mode selection component that enables the apparatus to switch from being capable of driving signals at the first and second output driver output nodes according to a first mode to being capable of driving signals at the first and second output driver output nodes according to a second mode, and vice versa.

A method for operating an output driver in accordance with at least two modes, the method comprising:

• receiving a mode select input at an output driver circuit;
• selecting an output driver circuit configuration corresponding to at least one of a first operational mode or a second operational mode responsive to the received mode select input by closing or opening, respectively, a switch that is connected in parallel with a resistive element;
• the output driver circuit including a differential pair that provides differential outputs for the output driver circuit;
• and
• driving the output driver circuit at the differential outputs according to at least one of the first operational mode or the second operational mode based on the selected output driver circuit configuration, the first operational mode corresponding to current mode logic (CML) signaling and the second operational mode corresponding to low voltage differential signaling (LVDS).

A method for operating an output driver in accordance with at least two modes, the method comprising:

• receiving a mode select input at an output driver circuit;
• if the mode select input comprises a first value, activating a switch into an open position;
• wherein the switch is connected in parallel with a resistive element and coupled between a supply voltage and an alternating current (AC) ground;
• if the mode select input comprises a second value, activating the switch into a closed position;
• if the switch is in the open position, driving the output driver circuit according to a first mode;
• and
• if the switch is in the closed position, driving the output driver circuit according to a second mode.

An arrangement comprising:

• amplification means for amplifying differential signals for transmission from first and second output nodes of an output driver;
• resistance means for providing a resistance between the amplification means and a supply voltage;
• and
• switching means for shorting the resistance means, the switching means adapted to enable a first output driver mode when the resistance means is shorted and to enable a second output driver mode when the resistance means is not shorted.

A method for operating an output driver in accordance with at least two modes, the method comprising:

• receiving a mode select input at an output driver circuit;
• selecting an output driver circuit configuration corresponding to at least one of a first operational mode or a second operational mode responsive to the received mode select input by respectively closing or opening a switch, the output driver circuit including a differential pair that provides differential outputs for the output driver circuit;
• and
• driving the output driver circuit at the differential outputs according to at least one of the first operational mode or the second operational mode based on the selected output driver circuit configuration, the first operational mode corresponding to current mode logic (CML) signaling and the second operational mode corresponding to low voltage differential signaling (LVDS).