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TPS23730EVM-093: Need design support

Danny Shrira
Prodigy 10 points
Part Number: TPS23730EVM-093
Other Parts Discussed in Thread: TIDA-050045, TPS23730

Hi Team,

We have purchased the a.m. EVM for a 20-69V input to 12V/2.5A output: we decided to adopt the design as is.

We now need to provide 5.25V/6A at the output so we changed the transformer from the original to Wurth's 750319033 and modified the feedback resistor R204 to 11.4K so to get the desired output level.

Can you pls. confirm:

1. The calculated 11.4K R204 value OK for the required 5.25V output? 

2. Do we have to modify anything else so stability is not compromised when we use an 11.4K R204 resistor?

If any additional information is needed we'll be glad to provide.

Thanks in advance

Danny Shrira

  • 0
    TI__Mastermind 21320 points

    Hey Danny, 

    The TIDA-050045 is the 5V version of the TPS23730EVM-093. 

    The differences between the designs is more than the transformer and feedback resistor. Only changing these two will likely result in a design that does not work. 

    Both of these designs have more power than you need, and neither have the full input range you require. They are designed for 50W applications and for the PoE IEEE802.3 standard input range (37-57). Of course you can use them at lower power levels, but they will not be the optimized solution when it comes to cost, size and performance. 

    The IEEE802.3 Class Boundary is 25W on the PD, so we have designs at 5V/5A. Otherwise we bump it up to the next Type level boundary at 51W --- which is what these designs are. 

    For the wide input range, if it is an adapter power source, I would suggest using a buck-boost to make the adapter a constant 48V and then combine it like we do in the EVM and TI Reference Design. 

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments 

  • 0
    Prodigy 10 points

    Thanks a lot, Michael.

    We will definitely study your reply and suggestion and proceed.

    Regards,

    Danny

  • 0 in reply to Danny Shrira
    Prodigy 10 points

    Hey Michael,

     

    Thanks again for your reply, but I'm afraid I wasn't clear enough, so pls. let me clarify:

     

    1. The input range we need to meet is 20V as a minimum while the maximum stated for PoE (57V) is fine with us, so sorry about the 69V max typo from yesterday.
    2. The output should be 5.25V (not 5V) at 6A at least.
    3. PoE is at the moment an option – most likely to be implemented in the future – so we initially we wish to work off a 24V desktop Universal Input adapter.
    4. We have also noticed that in the TIDA-050045 drawings the transformer – WE type 750318938 - is not the one shown in the EVB picture (LDT8627 ???): We have 750319033 in our stock. Can we use it for our task?
    5. Can you provide an updated schematic of TIDA-050045, that corresponds to your actual PCB layout, BOM, and assembling list?

     Based on the said above, we wish to work with the TPS23730 – which we have already purchased – including the 12V output EVM.

     

    Can you pls. suggest a solution matching our requirements?

     

    I am adding my office address for the reply: danny@coraldd.com

     

    Thanks in advance and best regards,

     

    Danny Shrira

  • 0 in reply to Danny Shrira
    TI__Mastermind 21320 points

    Hey Danny, 

    1. Neither design supports a 20V input. You will have to completely redesign the system to accommodate a 20V input. Here is a good paper on designing active clamp forwards -- https://www.ti.com/lit/an/slua535a/slua535a.pdf?ts=1647880682827 

    2. Got it, so since you need to redesign the system anyways, i would suggest designing it for 6A instead of 10A. You will get better efficiency, lower cost, and smaller magnetics

    3. The TPS23730 will work off of this. If you apply a voltage above the VDD_VSS threshold the IC will turn on. We use a DC power supplies in the lab to test this often. You will need to use the PPD pin to enable this to lower the turn on threshold down to 24V. 

    4. The TPS23730EVM-093 and the TIDA-050045 are built on the same board --- only a BOM change. Yes the TIDA-050045 picture is actually of the TPS23730EVM-093, but the physical boards are correct. 

    For the 750319033 , that's a really loose question. If you are saying you are going to copy the TIDA-050045 except for the transformer -- absolutely cannot use it. If you're planning to remake the design, then maybe, but it is unclear what the input voltage range is or what the power level is. If you design to use the 750319033 then you can probably use it, but I can't confirm for you if it meets your design needs. Work with Wurth to determine if it's correct. In  the end you will probably need to custom design your own transformer with Wurth (or your preferred vendor). 

    5. The schematic, BOM, layout and Assembly list are correct on TI.com. We had to custom define the transformers for both the TIDA-050045 and the TPS23730EVM-093. Therefore, we had to create custom symbols in Altium to correspond. Unfortunately the Altium team did not make them line up, so there is no good way to get around this. But the information on TI.com is correct/up to date, and the physical boards are built correctly. 

     

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments 

  • 0 in reply to Michael Pahl
    Prodigy 10 points

    Thanks Michael.

    It seems we need to do "a lot of thinking", as this issue seems to be getting a bit too complicated.

    Will review the paper you suggested and be in touch.