UC3842: how to calculate the number of turns for the pdf example

bogdan ardeleanu

Part Number: UC3842
Other Parts Discussed in Thread: UCC38C42

For the example in pdf I have not found a formula for finding the number of turns in the primary and secondary winding starting from the primary and secondary inductor of 1.5mH and 15uH respectively.

As a transformer I would like to use EE30. Please show me what formula to use to determine the number of turns.

over 7 years ago

0 John Stevens over 7 years ago

TI__Expert 7395 points

Bogdan,

Thanks for your interest in TI here.

The turns ratio and inductance are calculated in section 9.2.2.2 and 9.2.2.3 on pages 23 and 24.

Alternatively you could use Webench to calculate your design from the product folder here:

Additionally you may consider the most recent version of this part the ucc38c42.

Regards

John

0 bogdan ardeleanu over 7 years ago in reply to John Stevens

Prodigy 20 points

I'm interested in the number of turns not the transformation ratio.If it can be found in the transformation ratio, I'm interested in the formula

0 John Stevens over 7 years ago in reply to bogdan ardeleanu

TI__Expert 7395 points

Bogdan,
The best resource for that is here: www.ti.com/.../slup132.pdf
regards,
John

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UC3842: how to calculate the number of turns for the pdf example