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For 28V IN and 28V OUT application

Marco Failla
Prodigy 85 points
Part Number: LM25184EVM-S12
Other Parts Discussed in Thread: SN6507, UCC256403, , SN6501, LM25184

Tool/software:

Hi, 

we need a TI proper solution for an isolated switching power supply, with: high efficiency (>80 %), small footprint, few components.

Specifications: Input Voltage: 20 - 35 V (nominal = 28 V), Output Voltage = 28 V, Output current = 200 mA Max, switching frequency 400 - 1000 kHz.

We first tried an LLC solutions with UCC256403 but it can't work at high switching freq, then we tried the simple solution with SN6507 EVM, it's open loop so with no load the voltage raises too much and with load we can't get more than 65 % efficiency with our specifications.

Now we are looking to a PSR flyback solution: LM25184EVM-S12

So I have a simple question before to buy it, can it work with our specifications? 

Can I use it to get a 28V out, 5.6W max ? 

You could suggest us also other solutions, we are open to everything.

Thanks

  • 0
    TI__Mastermind 23116 points

    Hi Marco,

    Have you heard of the UCC1414 family? These are isolated, integrated power supplies we use for our isolated gate drivers. They can supply 2W and 25V. Switching frequency is 16MHz.

    We have an update to this device called "Havoc" that has pre-production samples available, which might be able to meet your 28V requirement, but only is 1.5W. The full preliminary datasheet is marked NDA, but here is a snapshot of the headline. Let me know if you want other details as needed.

    I like to avoid complexity, and SN6501 is often good enough for my purposes. It will be a challenge to supply 5.6W with a fully integrated solution. UCC14141 has lots of "protection" features that can be a nuisance if your application does not demand max efficiency and precision. But it sounds like a good fit here.

    Best regards,

    Sean

  • 0 in reply to Sean Cashin
    Prodigy 85 points

    Hello, 

    thanks for your reply. I don't search for integrate solution, but for a compact one with a good controller, a power transformer and few more components.

    The UCC1414 is not good for our purpose.

    It shouldn't use an optocoupler, so we are looking for PSR flyback.

    So we need some information about LM25184EVM-S12.

    Do we have a chance to get 28V out, 5.6 W max and good efficiency from it?

  • 0 in reply to Marco Failla
    TI__Mastermind 23116 points

    I have forwarded this thread to an engineer more familiar with that part.

  • +1 in reply to Marco Failla
    TI__Genius 15536 points

    HI Marco,

    Yes, you can use LM25184 when 20 - 35 V (nominal = 28 V), Output Voltage = 28 V, Output current = 200 mA Max. The fsw_max for this converter will be 350kHz when working in DCM. You can get >80% for efficiency. Please, fill the calculator tool (link below) to estimate your efficiency and transformer parameters.

    Thank you

    LM25183-LM25184DESIGN-CALC Calculation tool | TI.com