UCC28700-Q1: Removing Aux WInding?

?? ?

Part Number: UCC28700-Q1
Other Parts Discussed in Thread: UCC28700, TINA-TI

Hello,

my system has DC24V as input to supply UCC28700-Q1 with no need of an aux winding connected to Vcc. Is it possible to sample primary mosfet Vds instead of Vaux, since Vds is also scaled replica of the secondary winding voltage and contains information of output voltage? In this way I need only adjust resistors connected to VS pin according to ratio of Vds to Vaux, saving an extra aux winding.

Thanks for your reply.

3 months ago

0 Harish Ramakrishnan5 3 months ago

TI__Mastermind 22015 points

Hi Qi,

Thank you for the query on UCC28700.

The aux winding is used for a number of functions which are critical for the controller to run.

So it might be difficult to implement and not straight forward to implement. I do not see this implemented before from our end to show any references.

Regards,

Harish

0 ?? ? 3 months ago in reply to Harish Ramakrishnan5

Prodigy 20 points

Hi Harish,

i'm just trying to verify this idea with UCC28700 Tina-TI model from TI website. However I got the error "convergence problem".

Maybe you can shoot what is the trouble? Attached is my simulation file.

Thanks!
UCC28700 high side without aux winding.TSC

0 Harish Ramakrishnan5 3 months ago in reply to ?? ?

TI__Mastermind 22015 points

Hi,

Thank you for reaching out.

I see convergence error when these models are used in high side configuration. Not sure what could be affecting this. Honestly, the modelling support team is no longer available and we might not be able to support specific requests.

Regards,

Harish

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UCC28700-Q1: Removing Aux WInding?