US 9,851,772 B2Granted

1-wire bus PD detection and classification scheme for ethernet PoDL

AssigneeLinear Technology Corporation

InventorsDavid Dwelley, Andrew J. Gardner

Life of this patent

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Abstract

A PoDL system includes a PSE supplying DC power and Ethernet data over a single twisted wire pair to a PD. Prior to coupling the DC voltage source to the wire pair, the PD needs to receive sufficient power to perform a detection and classification routine with the PSE to determine whether the PD is PoDL-compatible. The PSE has a low current, pull-up current source coupled to a first wire in the wire pair via a first inductor. This pull-up current charges a capacitor in the PD to a desired operating voltage, and the operating voltage is used to power a PD logic circuit. The PD logic circuit and a PSE logic circuit then control pull-down transistors to communicate detection and classification data via the first wire. After the handshaking phase, the PSE then applies the DC voltage source across the wire pair to power the PD for normal operation.

Claims17

Dependent claims

A Power over Data Lines (PoDL) system for supplying power and data over a wire pair, the wire pair being a first wire and a second wire coupled to a Powered Device, the system comprising:

a Power Sourcing Equipment (PSE) side of the wire pair, the PSE side comprising:
a DC voltage source supplying a DC voltage;
a first low pass filter coupled to the first wire;
a first switch coupled between the DC voltage source and the first low pass filter for selectively coupling the DC voltage to the first wire;
a first pull-up current source coupled to the first low pass filter at a first node;
a first pull-down device coupled to the first node;
a first control circuit controlling the first switch and the first pull-down device;
and
a first differential data transceiver coupled to the wire pair via a first high pass filter;
a Powered Device (PD) side of the wire pair, the PD side comprising:
a second low pass filter coupled to the first wire;
a first capacitor coupled to the second low pass filter;
a second pull-down device coupled to the second low pass filter;
a second differential data transceiver coupled to the wire pair via a second high pass filter;
and
a second control circuit controlling the second pull-down device, wherein the first capacitor is coupled to a voltage input terminal of the second control circuit,
wherein, prior to the first switch being closed for coupling the DC voltage source to the first wire, the first pull-up current source charges the first capacitor to an operating voltage of the second control circuit to power the second control circuit, and
wherein the first control circuit and the second control circuit are configured to transmit and receive first serial data via the first wire by controlling the first pull-down device and the second pull-down device prior to the DC voltage source being applied to the first wire, such that the first pull-up current source provides power to operate the second control circuit while also being used to pull-up the first wire for transmitting serial data via the first wire.

15 more elements

A method performed by a Power over Data Lines (PoDL) system for supplying power and data over a wire pair, the wire pair being a first wire and a second wire coupled to a Powered Device, the method comprising:

Power Sourcing Equipment (PSE) providing a pull-up current to the first wire in the wire pair via a first low pass filter;
charging a first capacitor in the Powered Device (PD) by the pull-up current to achieve a desired operating voltage across the first capacitor;
coupling the first capacitor to an input voltage terminal of a first control circuit in the PD to operate the first control circuit;
controlling pull-down devices in the PD and PSE to selectively pull down the first wire to transmit first serial data between the first control circuit and a second control circuit in the PSE, the first serial data conveying operating characteristics of at least the PD;
only after the first serial data is processed by the PSE, coupling a DC voltage source to the first wire, via the first low pass filter, to supply operating power to the PD;
and
communicating between the PSE and the PD, using a first differential data transceiver in the PSE and a second differential data transceiver in the PD, via the wire pair and via high pass filters, such that the first serial data is communicated between the PSE and the PD, via the first low pass filter, and the first differential data transceiver and the second differential data transceiver bidirectionally communicate differential data via the wire pair and the high pass filters.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/831,632Filed 20 Aug 2015 · us provisional application
Priority: 22 Aug 2014
Published: US 2016/0054777 A125 Feb 2016
Granted: 26 Dec 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G06F 1/3206
Power management, i.e. event-based initiation of a power-saving mode: monitoring of events, devices or parameters that trigger a change in power…
G06F 1/263
Power supply means, e.g. regulation thereof: arrangements for using multiple switchable power supplies, e.g. battery and AC
G06F 1/3287
Power saving characterised by the action undertaken: by switching off individual functional units in the computer system
G06F 1/3296
Power saving characterised by the action undertaken: by lowering the supply or operating voltage