Method for high voltage power feed on differential cable pairs

A method to at least partially power an Ethernet network powered device PD, from an Ethernet power signal fed through an Ethernet network connection, comprising:

• physically coupling the Ethernet network PD to the Ethernet network;
• receiving an Ethernet signal from the Ethernet network, wherein the Ethernet signal comprises the plurality of power signals and/or data signal(s);
• passing the Ethernet signal an integrated circuit (IC), wherein the IC comprises a power feed circuit;
• separating with the IC, the data signal from the Ethernet signal, wherein the data signal is passed to an Ethernet physical layer (PHY) module;
• separating with the IC, the Ethernet power signal from the Ethernet signal, wherein the power signal is passed to the power management module;
• and
• at least partially powering the Ethernet network PD from the power signal.

A method to at least partially power an Ethernet network powered device PD, from an Ethernet power signal fed through an Ethernet network connection, comprising:

• receiving a plurality of paired Ethernet power signals;
• passing each pair of Ethernet power signal through a differential transistor pairs;
• sensing a drain voltage at a drain of each of the transistors within the differential transistor pair;
• comparing the drain voltages of each of the transistors within the differential transistor pair;
• producing control signals for of each of the transistors within the differential transistor pair based on the comparison of the drain voltages of each of the transistors within the differential transistor pair;
• applying the control signal to a gate of each of the transistors, wherein the control signal forces the Ethernet power signal passed by each of the transistors in a differential transistor pair to be equal;
• and
• passing the Ethernet power signal from a pair of output nodes wherein one output node is associated with each of the differential transistor pairs, and wherein the pair of output nodes feed power to the Ethernet network PD.

A power feed circuit operable to supply power to an Ethernet network powered device (PD) coupled to an Ethernet network, comprising an integrated circuit (IC) that further comprises:

• two differential transistor pairs wherein each of the transistors of the differential transistor pairs is operable to pass an Ethernet power signal;
• two pairs of impedance sense resistors, wherein each of the impedance sense resistors is coupled to a single transistor of the differential transistor pairs, wherein each of the impedance sense resistors is operable to pass Ethernet power signals received from a drain of the coupled transistor;
• an amplifier coupled to the drains of each of the transistors within a differential transistor pair, wherein the amplifier are operable to:
• amplify a differential voltage across the pair of impedance sense resistors coupled to the differential transistor pair;
• and
• apply a feedback signal to a gate of each of the transistors within the differential transistor pair coupled to the amplifier, wherein the feedback signal is based on the differential voltage, wherein the feedback signal forces the Ethernet power signal passed by each of the transistors in the differential transistor pair to be equal;
• and
• a pair of output nodes, wherein one output node is associated with each of the differential transistor pairs, and wherein the pair of output nodes feed power to the Ethernet network PD.