Invention Grant
- Patent Title: Power over data lines system using pair of differential mode chokes for coupling DC voltage and attenuating common mode noise
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Application No.: US16396566Application Date: 2019-04-26
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Publication No.: US10594519B2Publication Date: 2020-03-17
- Inventor: Gitesh Bhagwat
- Applicant: Linear Technology Holding LLC
- Applicant Address: US MA Norwood
- Assignee: Linear Technology Holding LLC
- Current Assignee: Linear Technology Holding LLC
- Current Assignee Address: US MA Norwood
- Agency: Patent Law Group
- Agent Brian D. Ogonowsky
- Main IPC: H04L25/02
- IPC: H04L25/02 ; H04B3/56 ; H04L12/40 ; G06F1/3234

Abstract:
In a Power over Data Lines (PoDL) system that conducts differential data and DC power over the same wire pair, various DC coupling techniques are described that improve DC voltage coupling while attenuating AC common mode noise. Pairs of differential mode chokes (DMCs) are used to share current supplied by a single phase or multi-phase power supply. In one embodiment, one DMC is coupled to the line side of a common mode choke (CMC), and one DMC is coupled to the PHY side of the CMC. The line-side DMC has windings that are loosely magnetically coupled so that DMC does not present a very low impedance to AC common mode noise on the wires. Therefore, the performance of the wires' RC termination circuitry is not adversely affected by the line-side DMC when minimizing reflections of common mode signals.
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