System and method for measuring current in hybrid power over ethernet architecture
AssigneeBroadcom Corporation
InventorMarius Ionel Vladan
Life of this patent
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Abstract
Systems and methods of measuring current in a power over Ethernet (PoE) system are provided. The PoE system includes an integrated circuit component having a controller, an internal transistor, a replica transistor, and an external transistor. Current in the system can be indirectly measured by enabling and disabling the transistors in known ways and then measuring the current through the replica transistor. The actual current in the system can be calculated based on the measured currents, thereby allowing for a PoE system that is capable of measuring current without a resistor in series with the external transistor.
Claims17
A method of indirectly measuring a load current IL in a power over Ethernet (PoE) system that includes a first transistor, a second transistor, and a replica transistor M times smaller than at least one of the first and second transistors, the method comprising:
- enabling both the first and second transistors and measuring an initial-state current IR1 through the replica transistor;
- disabling at least one of the first and second transistors and measuring a final-state current IR2 through the replica transistor;
- calculating a current factor kI based on the initial-state current IR1 and the final-state current IR2;
- and
- calculating the load current IL based on a measured present current IRP in the replica transistor and the current factor kI.
A power over Ethernet (PoE) system, comprising:
- an integrated circuit component that includes a controller, a first transistor, and a replica transistor, wherein the first transistor is coupled between a load and a ground;
- and
- a second transistor directly coupled between the load and the ground, wherein the second transistor is external to the integrated circuit component,
- wherein the controller is configured to:
- enable the first and second transistors prior to measuring an initial-state current I R1 through the replica transistor, disable at least one of the first and second transistors and measure a final-state current IR2 through the replica transistor, calculate a current factor kI based on the initial-state current IR1 and the final-state current IR2, and calculate a load current IL based on a measured present current IRP in the replica transistor and the current factor kI.
Dependencies are inferred from the claim text.