Method of discrimination of a device as powerable through a lan line and device for estimating electric parameters of a lan line
AssigneeSTMicroelectronics S.r.l.
InventorsAldo Torazzina, Riccardo Russo
Life of this patent
Estimating the term…
Abstract
PDs that can be supplied through the LAN line are discriminated from PDs that cannot be so supplied as a function of the resistance of the supply line and of the voltage drop caused by nonlinear elements in series therewith. The values of these two parameters are estimated by applying two distinct voltages to the supply terminals of the LAN line and sensing the relative steady-state currents absorbed by the power supply line, and by processing voltage and current values for estimating the resistance of the line and the voltage drop caused by nonlinear elements connected in series therewith.
Claims19
1-13. (canceled)
A method of recognizing a device as being powerable through a local area network (LAN) line coupled thereto based upon electrical parameters seen from first and second terminals of the LAN line comprising:
- applying a first voltage across the first and second terminals for a first time interval and sensing a first steady-state current;
- applying a second voltage different than the first voltage across the first and second terminals for a second time interval and sensing a second steady-state current;
- estimating a resistance of the LAN line based upon the first and second voltages, the first and second steady-state currents, and a voltage drop across a load coupled to the LAN line;
- and
- recognizing the device as being powerable through the LAN line based upon the resistance of the LAN line and the voltage drop across the load.
A method of recognizing a device as being powerable through a local area network (LAN) line coupled thereto based upon electrical parameters seen from first and second terminals of the LAN line comprising:
- applying a first voltage across the first and second terminals for a first time interval and sensing a first steady-state current;
- applying a second voltage different than the first voltage across the first and second terminals for a second time interval and sensing a second steady-state current;
- estimating a resistance of the LAN line based upon the first and second voltages, the first and second steady-state currents, and a voltage drop across a load coupled to the LAN line;
- switching a supply voltage of the LAN line from the second voltage to a third voltage and sensing a third steady-state current;
- estimating a capacitance of the LAN line seen between the first and second terminals, based upon the third steady-state current failing to reach a threshold;
- and
- recognizing the device as being powerable through the LAN line based upon the resistance of the LAN line, the voltage drop across the load, and the capacitance of the LAN line.
A device for estimating a resistance seen from first and second terminals of a local area network (LAN) line and a voltage drop across a load connected to the LAN comprising:
- a generator configured to generate at least first and second supply voltages;
- a buffer stage configured to replicate the first supply voltage on the first and second terminals for a first time interval;
- a current sensor configured to generate a corresponding digital signal representative of a first current absorbed by the LAN line as the first supply voltage is replicated on the first and second terminals;
- said buffer stage also configured to replicate the second supply voltage on the first and second terminals for a second time interval;
- said current sensor also configured to generate a corresponding digital signal representative of a second current absorbed by the LAN line as the second supply voltage is replicated on the first and second terminals;
- control circuitry configured to control the generator and to estimate a resistance of the LAN line based upon the first and second voltages, the first and second steady-state currents, and a voltage drop across a load coupled to the LAN line;
- said control circuitry also configured to recognize the device as being powerable through the LAN line based upon the resistance of the LAN line and the voltage drop across the load.
A device for recognizing a device as being powerable through a local area network (LAN) line coupled thereto based upon electrical parameters seen from first and second terminals of the LAN line, the device comprising:
- circuitry configured to apply a first voltage across the first and second terminals for a first time interval and sense a first steady-state current;
- circuitry configured to apply a second voltage different than the first voltage across the first and second terminals for a second time interval and sense a second steady-state current;
- control circuitry configured to estimate a resistance of the LAN line based upon the first and second voltages, the first and second steady-state currents, and a voltage drop across a load coupled to the LAN line;
- and
- said control circuitry further configured to recognize the device as being powerable through the LAN line based upon the resistance of the LAN line and the voltage drop across the load.
Dependencies are inferred from the claim text.