Power over data lines system providing a variable voltage to powered device

A method performed by a Power Over Data Lines (PoDL) system, wherein the system includes Power Source Equipment (PSE) coupled to a Powered Device (PD) via a wire pair, wherein differential data signals and DC power are transmitted over the same wire pair;

• the method comprising:
• applying an input voltage to a variable voltage converter in the PSE and outputting a regulated voltage;
• carrying out a low power handshaking phase over the wire pair to at least identify whether the PD is compatible for receiving an operating voltage over the wire pair and to identify a particular voltage requirement of the PD, wherein voltages within a first voltage range are carried by the wire pair during the handshaking phase;
• controlling the variable voltage converter to output a voltage on the wire pair corresponding to the particular voltage requirement of the PD identified during the handshaking phase wherein the particular voltage requirement of the PD is allowed to be below or within the first voltage range;
• detecting a DC voltage on the wire pair, by an Undervoltage Lockout (UVLO) circuit in the PD, and determining whether the voltage is above a threshold voltage;
• coupling the wire pair conducting a voltage above the threshold level, by the UVLO circuit, to a PD load after the handshaking phase;
• and
• preventing coupling the wire pair conducting a voltage above the threshold level, by the UVLO circuit, to the PD load if the voltage above the threshold level occurs during the handshaking phase.

A Power Over Data Lines (PoDL) system comprising:

• a Powered Device (PD) configured for connection to Power Source Equipment (PSE) via a wire pair, wherein differential data signals and DC power are transmitted over the same wire pair;
• the PD comprising a PD controller configured to carry out a low power handshaking phase over the wire pair to at least identify whether the PD is compatible for receiving an operating voltage from the PSE over the wire pair and to identify to the PSE a particular voltage requirement of the PD, wherein voltages within a first voltage range are carried by the wire pair during the handshaking phase,
• wherein the particular voltage requirement of the PD is allowed to be below or within the first voltage range;
• and
• an Undervoltage Lockout (UVLO) circuit in the PD configured to detect a DC voltage on the wire pair and determine whether the voltage is above a threshold voltage,
• wherein the UVLO circuit is configured to couple the wire pair conducting a voltage above the threshold level to a PD load after the handshaking phase, and
• wherein the UVLO circuit is configured to prevent coupling the wire pair conducting a voltage above the threshold level to the PD load if the voltage above the threshold level occurs during the handshaking phase.

A Power Over Data Lines (PoDL) system comprising:

• a first means configured for connection to a second means via a wire pair, wherein differential data signals and DC power are transmitted over the same wire pair;
• the first means comprising a first controller configured to carry out a low power handshaking phase over the wire pair to at least identify whether the first means is compatible for receiving an operating voltage from the second means over the wire pair and to identify to the second means a particular voltage requirement of the first means, wherein voltages within a first voltage range are carried by the wire pair during the handshaking phase,
• wherein the particular voltage requirement of the first means is allowed to be below or within the first voltage range;
• and
• third means in the first means configured to detect a DC voltage on the wire pair and determine whether the voltage is above a threshold voltage,
• wherein the third means is configured to couple the wire pair conducting a voltage above the threshold level to a load in the first means after the handshaking phase, and
• wherein the third means is configured to prevent coupling the wire pair conducting a voltage above the threshold level to the load if the voltage above the threshold level occurs during the handshaking phase.