Patent ID: 8026627

Claim:
A Powered Device (PD) for use in a Power over Ethernet (PoE) system, comprising: a PD chip that receives a DC port voltage from a Power Source Equipment (PSE), said PSE connected to the PD by a cable; a first circuit, coupled to said DC port voltage, operable when said DC port voltage is within a detection voltage range of said PD chip to provide a detection signature of said PD chip to said PSE; a second circuit, coupled to said DC port voltage, operable when said DC port voltage is within a classification voltage range of said PD chip to provide a classification signature of said PD chip to said PSE; and a third circuit, coupled to said DC port voltage and to said second circuit, that receives said classification signature from said second circuit and that dynamically determines a turn on voltage and a turn off voltage of said PD chip based on said classification signature and a maximum voltage drop across said cable; thereby allowing said PD chip to operate when said received DC port voltage during a post startup phase is lower than an IEEE compliant minimum voltage for said post startup phase.