| US 7,548,799 B2 | ||
| Powered device including a detection signature resistor | ||
| D. Matthew Landry, Austin, Tex. (US); and Russell J. Apfel, Austin, Tex. (US) | ||
| Assigned to Silicon Laboratories, Inc., Austin, Tex. (US) | ||
| Filed on Jul. 25, 2006, as Appl. No. 11/492,367. | ||
| Prior Publication US 2008/0024106 A1, Jan. 31, 2008 | ||
| Int. Cl. G06F 1/26 (2006.01) | ||
| U.S. Cl. 700—297 [324/533; 323/267] | 19 Claims |
| 6. A powered device comprising:
an interface responsive to a powered network;
a first node responsive to an external resistor;
a switch to selectively couple the first node to a voltage supply terminal;
a power over Ethernet (PoE) detection circuit responsive to a detection voltage from the interface and to selectively activate
the switch to couple the first node to the voltage supply terminal; and
a reference current generator responsive to the first node to generate a reference current related to the external resistor
when the switch is inactive;
wherein the external resistor comprises a resistor having a resistance value that is approximately 25 K-ohms.
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