Coss of Sync Fet on TPS54610

Ben van den Bergh

Prodigy 30 points

Other Parts Discussed in Thread: TPS54610

Hello, Could anybody please provide me with the Coss value for the "bottom" Sync Fet for the TPS54610

The reason for this is to enable us to calculate the external snubber RC network.

Thank you

over 15 years ago

0 Michael Krasnicki over 15 years ago

TI__Expert 3875 points

Hi Ben,

I am not really sure what you mean by "Coss". SwitcherPro uses 330pF as the output capacitance for each of the sync FETs. If this does not answer your question, I can transfer your question to the "Non-Isolated DC/DC" forum.

Hope this helps,

Michael

0 Ben van den Bergh over 15 years ago in reply to Michael Krasnicki

Prodigy 30 points

Yes thank you the information correlates well with the value which I arrived at using an empirical technique

The process is quite simple, Insert a cap across the snubber position and substitute with different value until the ringing frequency halves

The value of this cap divided by four is +/- Coss.

The experimental value was 335pF the cap used measured 1.34nF on our LCR bridge (supposed to be 1.5nF cap).

0 Ben van den Bergh over 15 years ago in reply to Ben van den Bergh

Prodigy 30 points

Some additional information that might prove useful to anybody having to implement a snubber

Application note "slup 100" Snubber Circuits: Theory, Design and Application by Philip C Todd.

proved very informative.

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Coss of Sync Fet on TPS54610