DC/DC Converter

Bosco N

Prodigy 30 points

Other Parts Discussed in Thread: TIDA-010081, UCC28911, UCC25640, UCC25660, UCC25660EVM-064

Hi,

I would like to know if TI has DC/DC converter support for our below-required specification.

I/P= 400VDC

O/P=48Vdc @ 20Amps.

Kindly support

Thanks

Bosco

9 months ago

0 JCHK 9 months ago

TI__Mastermind 44220 points

Hi Bosco,

Have a look at TIDA-010081 and see if that can work for you. Here is a Webench-based design you can also refer to. We are about to pre-release our latest LLC controller which will go live any day now. Here is a selection guide highlighting some of the new features.

I hope this answers your question.

0 Bosco N 9 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks.

I went through TIDA-010081 , but i see the i/p is AC type.

But I need I/P= 400VDC and O/P=48Vdc @ 20Amps.

Pl., suggest

Regards

Bosco

0 JCHK 9 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

The output of the PFC stage is normally 400V. So if you connect your 400V after the PFC this should be close to what you are looking for.

Does this answer your question?

0 Bosco N 9 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks. That's nice.

Hope, I can continue the design from the Vbus circuit with out any design changes, including the transformer, etc.

also wanted to check if any filter circuit is required in between the Vbus line? If yes can you pl., suggest one.

Thanks

Bosco

0 JCHK 9 months ago in reply to Bosco N

TI__Mastermind 44220 points

HI Bosco.

You shouldn't need to change anything if you are happy with the current output power stage. Since I don't know how you are providing the 400V, it is not easy to suggest what filtering may be required. For the LLC input stage, the key is to have enough bulk capacitance on VBUS.

Regards,

John

0 Bosco N 9 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks for your quick response and support.

The 400Vdc o/p which I provide comes from power supply with high power (400VDC @40Amps ). That's the reason wanted to check if any filter is required.

Also wanted to know if this high power(400VDC @40Amps). can be given to the VBus line. without any component change?

Thanks

Bosco

0 JCHK 9 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

Yes, the power stage of the reference design is optimized for ~18.5A. Having the input supply capable of supporting more power only ensures the VBUS can be robust over the full load. Keep in mind the current out of the supply is far less than the load current. This should be less than 3A on the input side.

0 Bosco N 9 months ago in reply to JCHK

Prodigy 30 points

Hi John,

I'm not getting this point " Keep in mind the current out of the supply is far less than the load current. This should be less than 3A on the input side."

which you have mentioned. Can you pl., clarify

Thanks

Bosco

0 JCHK 9 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

Think of it in terms of power, if you are delivering 48V at 20A this is 960W of power. On the input side assuming 100% conversion efficiency 960W/400V= 2.4A. If your LLC stage is 90% efficient, that would only raise the input current to around 2.7A.

Does this make sense.

0 Bosco N 8 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks for clarifying.

Regards
Bosco

0 Bosco N 8 months ago in reply to Bosco N

Prodigy 30 points

Hi John,

I need to make some changes to the calculations to achieve 48V @ 20A. and I see all the calculation formulas in the design guide.

It would be nice if you could share the design calculations excel sheet to speed up

Also, I don't see calculations for the AUX circuit, and transformer. pl., share

Thanks

Bosco

0 JCHK 8 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

Do you mean the Aux winding that provides the pri_15V rails? This is produced with the UCC28911's aux winding. The Excel calculator for that device is here. The Excel calculator for the UCC25640 is here.

Also, we just pre-released our latest LLC UCC25660. This newer controller might be even easier to use as it is less sensitive to layout.

I hope this helps.

0 Bosco N 8 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks for sharing the required details and the latest part.(will consider this).

Regarding the AUX supply, I did not find any transformer calculations. The one below T2.

P.S: I have downloaded the excel calculations yet to see if the AUX transformer calculation is included.

Thanks

Bosco

0 JCHK 8 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

The Aux calculations start at row 85 in the Excel calculator:

Regards,

Jojhn

0 Bosco N 8 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks. Got it

Regards

Bosco

0 Bosco N 8 months ago in reply to JCHK

Prodigy 30 points

Hi John,

I had gone through the latest LLC UCC25660 which you suggested, and seems this is a better device.

Kindly share the design files(design guide, sch, BOM, gerber, PCB layout etc) for UCC25660EVM-064.(This would be a good ref for me)

Thanks

Bosco

0 JCHK 8 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

I have requested our applications engineer to send these your way.

Regards,

John

0 Bosco N 8 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks for the support

Regards

Bosco

0 JCHK 8 months ago in reply to Bosco N

TI__Mastermind 44220 points

HI Bosco,

You are welcome!

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Hi John,

I had mailed you my requirement calculation sheet.

Can you please check and update?

Thanks

Bosco.N

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

I have requested our applications expert on this device to review in detail. Unfortunately, he will not be back in the office until December 3rd.

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Hi John,

Thanks. Will wait for response from your application expert.

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

Thank you for your patience. I hope to get an answer to you by Monday.

0 JCHK 7 months ago in reply to JCHK

TI__Mastermind 44220 points

Hi Bosco,

My applications expert confirmed your calculations are OK. You can proceed with the design with the current values.

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Thanks, John.

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

You're welcome!

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Hi John,

I couldn't find the UCC25660EVM model simulation on the website.

pl., do provide the download link.

Thanks

Bosco.N

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

HI Bosco,

It is not on the website yet, but it should be soon. The delay was trying to speed up the model so it runs faster. This is a Simplis model, is that something you can use? Otherwise, it might be best to request an EVM.

Regards,

John

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Hi John

Thanks.

I was looking for Pspice or Simplis model.

Regards,

Bosco

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

Hi Bosco,

I sent you a pre-release of the SIMPLIS model.

I hope this helps you get started.

0 Bosco N 7 months ago in reply to JCHK

Prodigy 30 points

Thanks, John

0 JCHK 7 months ago in reply to Bosco N

TI__Mastermind 44220 points

You're most welcome

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