UCD7138: UCD3138

robin gangopadhya18

Part Number: UCD7138
Other Parts Discussed in Thread: UCD3138

Is there an Xl spreadsheet ( or mathcad) calculation tool for the design of LLC converter parameters used in the system implied in the tidrn83.pdf?

over 4 years ago

0 Yitzhak Bolurian over 4 years ago

TI__Mastermind 18370 points

An expert will get back to you soon.

0 Sean Xu over 4 years ago in reply to Yitzhak Bolurian

TI__Genius 13570 points

I don't think so.

0 robin gangopadhya18 over 4 years ago in reply to Sean Xu

Mastermind 6050 points

Yitzhak:

Thanks for pointing this out.

Question then: for parameters used in the design guide for interleaved LLC using TMS320F28379, they show 62uH inductor!

In another app using UCD3138, noninterleaved LLC case, they have 2.3 uH. UCD3138 is running at higher switching frq- not substantially.

Almost 30 fold! Same Cr. Same power. Same input.

One would think freq was 6 times higher for UCVD3138.

But not so.

Is there any specific reason why Lr in C2000 case would be so much higher?

We will calculate that for sure...but I would like to explore why this vast difference.

It matters when you are trying to reduce packaging to the least possible vol , maximize efficiency etc...

appreciate any illumination of this matter.

0 Sean Xu over 4 years ago in reply to robin gangopadhya18

TI__Genius 13570 points

The resonant frequency comes from resonant inductor and transform leakage inductance. even though it output the same power, but the switching frequency can be different

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UCD7138: UCD3138