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seek for appropriate SMPS

Jenny Lu69
Expert 1810 points
Other Parts Discussed in Thread: UCC28700, LM3481, LM5022, PMP20745

Hello engineers,

we are in need of SMPS with supply range of 20-265VAC with isolated outputs as Output 1: 25VDC at 70mA w.r.t GND1, Output 2: -5VDC at 25mA w.r.t GND1, Output 3: 22VDC at 30mA w.r.t GND2, Output 4: -5VDC at 20mA w.r.t GND2. Could you please help us by providing solution for the same? You can chose best suitable IC for this requirement, I am not bound to UCC28700. Thanks for your offer to help.

Regards,

Jenny

  • 0
    TI__Genius 9130 points
    Jenny,

    The input voltage range of 20-265 V ac is very wide and not so common.


    You can search the range of available TI Designs and Reference Designs here:
    www.ti.com/.../refdesignsearchresults.tsp

    If you click on the tab “search power designs by parameters” you can search & refine according to your requirements.


    I searched for 20-265 V range (or close to that) and found a few possibilities.

    None are an exact match, but you could use these as a starting point and scale the power, and add more transformer secondary windings to generate the extra output voltage that you need:

    www.ti.com/.../PMP10098
    This is an isolated Flyback for 19-265 V input, with a single 12-V output at 0.5 W, using LM3481. This would need to scale the power up, adjust the number of secondary turns for the required main 25-V out, and add more secondary windings for the extra outputs.

    www.ti.com/.../PMP20745
    This is an isolated Flyback for 18-400 V DC input (would need to add bridge rectifier and EMI filter for AC input), with a single 15-V output @ 9 W, using LM5022. This would need to scale the power down (you only need ~3 W), adjust the number of secondary turns for the required main 25-V out, and add more secondary windings for the extra outputs.

    www.ti.com/.../PMP10200
    This is an isolated Flyback for 25-520 V DC input (would need to add bridge rectifier and EMI filter for AC input), with a single 28-V output @ 20 W, using UCC28700. This would need to scale the power down (you only need ~3 W), maybe adjust the number of secondary turns for the required main 25-V out, and add more secondary windings for the extra outputs.

    I hope this helps to get you started.

    Thanks,
    Bernard
  • 0 in reply to Bernard Keogh
    Expert 1810 points

    Hi Bernard,

    Thank you for showing options with various designs.
    I looked at all three designs and based on efficiency data and complexity of design I think PMP20745 is best suitable option. Now I seek your help to design circuit for our requirement based on PMP20745.
    Could you please help us to do the same?

    Our specs are as below
    Supply range of 20-265VAC
    Output 1: 25VDC at 70mA w.r.t GND1,
    Output 2: -5VDC at 25mA w.r.t GND1,
    Output 3: 22VDC at 30mA w.r.t GND2,
    Output 4: -5VDC at 20mA w.r.t GND2

    Thanks again.

    Regards,

  • 0 in reply to Jenny Lu69
    TI__Intellectual 880 points
    Hi Jenny,

    I would suggest using the PMP20745 for the input stage for the very wide Vin and then using the design guide for the TIDA-00706, which is a 25W multiple output flyback design and therefore needs to be scaled down to your design, to aid you in choosing transformer specifications and other components (design guide link here: www.ti.com/.../tidubk6a.pdf).

    Another design guide I would recommend is the TIDA-00708, which is a 1W multiple output flyback design, and I think it goes into a little bit more detail when selecting transformer turns ratio.
    Link to design guide for the TIDA-00708: www.ti.com/.../tidubk7b.pdf.

    Regards,
    Davit