US 10,594,367 B1Granted

Power over data lines system with accurate and simplified cable resistance sensing

AssigneeLinear Technology Holding LLC

InventorGitesh Bhagwat

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Abstract

In a PoDL system, where DC power and differential data are supplied over the same conductors between a PSE and a PD, a low-power test is first performed to determine the conductor resistance. The PSE and PD are connected to the conductors via DC-coupling inductors that block the data signals. Such inductors have a DC resistance (DCR). To avoid the DCR of the PD inductors being included in the resistance test of the conductors and to avoid the requirement of additional pins for kelvin sensing, the PD includes a MOSFET switch connected across the conductors on the line-side of the PD inductors. The PSE applies a current pulse of a known value to one of the conductors while the MOSFET switch is temporarily closed. The PSE measures the resulting voltage across the wires and uses Ohm's law to more accurately calculate the resistance of the conductors.

Claims21

Dependent claims

A Power over Data Lines (PoDL) circuit including Power Sourcing Equipment (PSE) for supplying DC power to a Powered Device (PD) over a first conductor and a second conductor, the PoDL circuit comprising:

the PD comprising:
a PD load powered by a DC voltage coupled across the first conductor and the second conductor;
a first DC-coupling inductor coupled between the first conductor and the PD load;
a second DC-coupling inductor coupled between the second conductor and the PD load;
a first switch, controlled by the PD, coupled across the first conductor and the second conductor, the first switch being controllable for temporarily creating a low resistance path between the first conductor and the second conductor;
the PSE comprising:
a current source for supplying a current pulse to the first conductor so that the current pulse flows through a loop including the first conductor, the first switch, and the second conductor without flowing through the first DC-coupling inductor and the second DC-coupling inductor;
and
PSE logic circuitry configured for calculating a resistance of the loop using a level of the current pulse and a voltage on at least one of the first conductor and the second conductor.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/518,683Filed 22 Jul 2019 · us provisional application
Priority: 7 Nov 2018
Granted: 17 Mar 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H04B 3/54
Line transmission systems: systems for transmission via power distribution lines
H02J 1/06
Circuit arrangements for DC mains or DC distribution networks: two-wire DC power distribution systems
H04L 12/10
Details: current supply arrangements
H04L 12/40045
Architecture of a communication node: details regarding the feeding of energy to the node from the bus