UCC28950: UCC28950

Hi Hamidi,
Thanks for your interest in UCC28950. Can you offer more information about the project spec for the XLS file calculation? Or you can send me the xls file of UCC28950 after you fill in the parameter.
For the shim inductor, the energy of this inductor is trying to charge and discharge the Coss energy of the primary mos. in the UCC28950 xls file, the average Coss is a roughly estimation.
From the xls file, if the Llk of transformer is big enough, then the Ls will be negative and Ls might not needed. As I said, the Coss of Primary mos is nonlinear and hard to do precise estimation, so it is better to left the place for the Ls for debugging in case we need to optimize the ZVS at the target load.
for the dead time setting, I would suggest you follow the datasheet Page 56-58.
thanks.

HI DAVID 

I ATTACH FOR YOU XLS FILE AND MY MOSFET DATASHEET AND TRANS FORMER CORE INPUT 390V OUTPUT IS 180V 20A

TRANSFORMER 10:5:5 ER64/13/51 

PLEASE ADVISE MIN L IS POSSIBLE FOR EASY SETUP AND DEBUG 

NOW I PUT 2.2UH BOUT IN NO LOAD ZVFS DEAD TIME SO BIG AND HAVE OVER SHOT SOME TIME DIODE PULL UP TO VCC ON TRANSFORMERE PIN DAMAGE (600V 3A) OVER 600V COME TO DIODE

NOTE ONE SECONDARY TRANSFORMER I DONT USED MOSFET ONLY USED 2 FAST DIODE BECUSE CURRENT NOT TO HIGH SOME TIME OVER VOLTAG DAMAGE DIODE (600V 30A)

MY BE NEED ADD CLAMP ?

 

BEST REGARDS 

OMID HAMIDI

ER64_13_51.pdf

DAVID.rar

Hi Hamidi，
Bigger Ls will cause more current through primary clamped diode. 2.2uH for the Ls is OK to me.
I can not follow your question, do you mean the primary clamped diode damaged?
What kind of clamped diode do you use, can you send me the datasheet?

HI DAVID 

THANKS for your follow my problem 

I test two diode I attach for you datasheet 

is possible give me one email addres i will send more data to you

best regards

omid hamidi

ES3J_datasheet.pdfES5J.pdf

Hi Hamidi,
my email is :wenbin-huang@ti.com.We can discuss this issue through email.