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LM5045: AC/DC converter. In: 230 and Out: 70VDC 10A

HARINI KRISHNA
Expert 1905 points
Part Number: LM5045
Other Parts Discussed in Thread: UCC3895, UCC28950

Hi,

Any suggestions or reference designs regarding the AC/DC converter AC-In: 160 to 265V and Isolated out 70VDC and 10A. 

I tried searching web-bench and forum but I could not find any. 

Appreciate your help

  • 0
    TI__Mastermind 32975 points

    Hi Harini,

    160 Vac<VIN<265 Vac

    Pout=700 W

    Vout=70 V

    Iout=10 A

    I believe the reason you are having difficulty finding a reference design to these requirements is because most/all will have a PFC from end with a dc-dc operating from a 400 Vdc input, allowed to discharge the hold-up capacitor down to some minimum acceptable voltage such as 300 V-350 V. Just to confirm, are you sure you are asking for a 700 W, ac-dc design, with no PFC boost? What is the application of such a design? If so, then you are simply rectifying the ac voltage and your dc-dc input becomes:

    220 Vdc<VIN<375 Vdc

    In this case your VIN range is 1.7:1, and I would suggest UCC28950 (or UCC3895 if no SR is desired). A good step by step reference guide is SLUA560c which is 370 Vdc<VIN<410 Vdc and 12 V, 50 A output. 600 W can be scaled to your 700 W power level with slight modifications to the transformer and secondary rectification.

    Regards,

    Steve M

  • 0 in reply to Steven Mappus1
    Expert 1905 points

    Hi Steve, 

    Thank you for your response. 

    Ok as you say most/all of them have PFC from the dc-dc side. I am not sure if our application needs PFC for 700W AC/DC converter and our application is to charge a Li-Ion battery Pack 60V 26AH basically to fast charge the battery pack. I would love to hear your suggestion weather to go with PFC or not for our application. 

    Thank you for the resource SLUA560C.

  • 0 in reply to HARINI KRISHNA
    TI__Mastermind 32975 points

    Harini,

    For 700 W operating from AC input, I would think you should be looking at a PFC front end. You are near the upper limit for interleaved transition mode (TM) PFC but since your AC input voltage is high, interleaved TM could be a great solution for this application. If you want a simple solution, TI offers a wide range of continuous conduction mode (CCM) PFC controllers that can easily handle 700 W. In either case, having a PFC front end will also simplify your dc-dc converter design, following the guidance I offered in my previous response.

    Regards,

    Steve M