Determination of Effective Resistance Between a Power Sourcing Equipment and a Powered Device

A system for determining an effective resistance between a power sourcing equipment and a powered device, the system comprising:

• a first power sourcing equipment;
• a first voltage measuring means associated with said first power sourcing equipment;
• a control circuitry responsive to said first voltage measuring means;
• a powered device, comprising a powered device interface and a powered device operational circuitry, arranged to receive power from said first power sourcing equipment;
• a second voltage measuring means associated with said powered device interface;
• and
• a current level impresser associated with said powered device interface,
• said powered device interface being operable responsive to said second voltage measuring means to:
• prior to connecting power to said powered device operational circuitry, impress, via said current level impresser, two disparate current flow levels (I1, I2) between the first power sourcing equipment and the powered device interface;
• and
• measure, via said second voltage measuring means, the voltage at said powered device interface (VPD1, PPD2) responsive to said impressed two disparate current flow levels,
• said control circuitry being operable to:
• measure, via said first voltage measuring means, the voltage at said first power sourcing equipment (VPSE1, VPSE2) responsive to said impressed two disparate current levels;
• and
• determine the effective resistance between said first power sourcing equipment and said powered device interface responsive to said VPD1, PPD2, VPSE1, VPSE2, I1 and I2.

A powered device interface operable in cooperation with a power sourcing equipment to determine an effective resistance there between, the powered device interface comprising:

• a control circuitry;
• a voltage measuring means in communication with said control circuitry;
• a current level impresser responsive to said control circuitry;
• and
• an isolating switch control means responsive to said control circuitry,
• said control circuitry being operable to:
• impress, via said current level impresser, two disparate current flow levels (I1, I2);
• measure, via said second voltage measuring means, the voltage at said powered device interface responsive to said impressed two disparate current flow levels;
• and
• subsequent to said sourcing two disparate current flow levels, operate said isolating switch control means to connect power to associated powered device operational circuitry.

A powered device operable in cooperation with a power sourcing equipment to determine an effective resistance there between, the powered device comprising:

• a powered device interface;
• a powered device operational circuitry;
• a voltage measuring means associated with said powered device interface;
• a current level impresser associated with said powered device interface;
• and
• an isolating switch responsive to said powered device interface,
• said powered device interface being operable to:
• to impress via said current level impresser, prior to connecting power to said powered device operational circuitry via said isolating switch, two disparate current flow levels (I1, I2);
• and
• measure, via said second voltage measuring means, voltages at said powered device interface responsive to said impressed two disparate current flow levels.

A power sourcing equipment operable to determine an effective resistance between the power sourcing equipment and a powered device connected thereto, comprising:

• a control circuitry;
• a voltage measuring means arranged to measure a port voltage of the power sourcing equipment and in communication with said control circuitry;
• and
• a current measuring means arranged to measure a current flowing between the power sourcing equipment via the port and the powered device,
• said control circuitry being operable to:
• supply an operating voltage to the powered device via the port;
• detect, via the current measuring means two disparate current flow levels (I1, I2) between the power sourcing equipment via the port and the powered device responsive to the supplied operating voltage;
• receive an indication of the voltage at the powered device (VPD1, PPD2) responsive to said two disparate current flow levels;
• measure, via said voltage measuring means, the port voltage of the power sourcing equipment (VPSE1, VPSE2) responsive to said detected two disparate current levels;
• and
• determine the effective resistance between the power sourcing equipment and the powered device responsive to said VPD1, PPD2, VPSE1, VPSE2, I1 and I2.