TPS2384 PD Classifacation issue

Kin Wu

Prodigy 10 points

Other Parts Discussed in Thread: TPS2384

Hi,

I connected a class 2 PD to TPS2384, but got the class 1 value from TPS2383.

Is it possible this behavior appear?

What kind of modification i can do if I want to fix this issue.

Thank you,

Kin Wu

over 14 years ago

0 Eric Wright over 14 years ago

TI__Mastermind 42795 points

Port capacitance can affect this function. 0.22uF is recommended across the PSE port (between Px and Nx) but you can increase to 0.33uF.

0 Guenter Fettig over 11 years ago in reply to Eric Wright

TI__Intellectual 1540 points

Can only port capacitance affect this function, or are there other possibilities as well ?

My customer is using 2x100nF 10% X7R Ceramic in parallel and facing classification issues even at proper current level.

Can a capacitor increase to 220nF< C < 330nF ensure proper classification ?

0 Eric Wright over 11 years ago in reply to Guenter Fettig

TI__Mastermind 42795 points

Please further describe the issue (ie, class 3 current reporting as class 0 or other mis-classification?). Sometimes class problems can be observed at the PSE port as an oscillation in the port waveform (very low level oscillation so you have to zoom in on the port class voltage using an oscilloscope).

Increasing Cport even up to 470nF is acceptable.

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TPS2384 PD Classifacation issue