Need help in designing buck power supply

KDN Nandu

Intellectual 750 points

Other Parts Discussed in Thread: LM5118, LM5116, LM5119

I am looking for power supply with input 24VDC and output 12VDC with 50A.

I need help in selecting inductor and and MOSFET.

over 10 years ago

0 KDN Nandu over 10 years ago

Intellectual 750 points

And selecting switcher also

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

You might start here:

It is a 12 V output at 50 A, with a slightly higher input voltage range. You could likely modify the basic design for lower input voltage.

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

LM5116MH is too much costly, any alternative of it?

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

There may be other alternatives, but that is the solution that I could find. I think you are going to find that to get 600W output will not be inexpensive. The prices on the web are 1k qty. You can probably do a lot better depending on your quantity. How many are you planning to build?

0 KDN Nandu over 10 years ago in reply to KDN Nandu

Intellectual 750 points

Do LM5116MH and LM5118 are equivalent?

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

No LM5116 is synchronous buck controller, LM5118 is non synchronous buck boost controller.

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

Total cost is around $68

I need around $20

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

I can typically help with technical questions. BOM cost is greatly determined by your supply chain. For lower cost you might look at LM5119 dual controller. The reference design for it is 28V output though.

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

Can you provide me reference design.

why we need dual controller, can't we do with single controller?

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

Typically there will not be enough gate drive from a single controller with integrated gate drivers to support that much load current. I cannot personally provide you with any reference design. We do have a design services group that may assist you. Can you tell me about your end application and the yearly production volumes?

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

MOSFET gate come with capacitive loading , which consume too less current , can you tell me how to calculate Gate driver current of MOSFET.

Datasheet give with information

IOHL Peak LO Source Current VLO = 0 V 1.8 A
IOLL Peak LO Sink Current VLO = VCC 3.5 A

IOHH Peak HO Source Current VHO = 0 V 1 A
IOLH Peak HO Sink Current VHO = VCC 2.2 A

I think 3.5 A and 2.2 A are sufficient to drive gate of MOSFET

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

There should be sufficient information in th edata sheet to help you design your circuit and choose switching FETs. There are probably lots of app notes on line as well.

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

Is their any technical document from TI for calculation gate current of MOSFET at different switching frequency?

0 JohnTucker over 10 years ago in reply to KDN Nandu

TI__Guru**** 191445 points

You could start here perhaps:

www.ti.com/.../slpa009a.pdf

You can also go here and use the search function at the top of the page to look for other technical documents:

www.ti.com/.../power_portal.page

0 KDN Nandu over 10 years ago in reply to JohnTucker

Intellectual 750 points

Here Input range is 35V to 60V, can I connect 24V at input to get 12Vdc at output ?

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Need help in designing buck power supply