O'Reilly logo

Power Over Ethernet Interoperability Guide by Sanjaya Maniktala

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Resumption after “Error” and Timings
A failed inrush phase (where the current may have exceeded the inrush template for example), or a severe overload or a short-circuit, or a port-voltage droop outside operating limits, are all “error” (fault) conditions that cause the port to be shut down. What happens thereafter?
The PSE first declares “power removal” by turning its pass-FET totally non-conducting (“OFF”), and also activates a timer called the TED (error delay) timer. Note that after declaration of power removal, the port voltage still needs to be brought below 2.8 V, since port capacitances are charged up. This can be done actively by the PSE, where it places a large bleeder resistor (> 45 k) across the port. In a test setup, the standard ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required