Hi!
We all know that Type 2 PD needs two cycles detection to decrease risk of detection failure, while Type 1 only needs one cycle in TI's chips. The question is:
Why there should be TWO cycles detection?
Thank you very much if you can kindly answer me this question.
Regards.
Hello Wenhao,
2 point detection occurs so that the detection resistance can be measured accurately. When you take two measurements & subtract their differences, you are removing their common error from noise/impedance/other parasitics across the long Ethernet cable.
Our PSEs do 4 point detection (where all 4 measured currents & voltages are compared against each other) because even 2 point detection can be fooled.
Best,
Tom
