• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 1010 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC28722: UCC28722 to generate 5V@ 50mA and +/-12V@ 30mA from (85VAC - 440VAC, 50/60Hz)

Dinesh Kumar41
Prodigy 60 points
Part Number: UCC28722
Other Parts Discussed in Thread: PMP10236

Hello UCC28722 Team,

We are using UCC28722 to generate 5V@ 50mA and +/-12V@ 30mA .

The input voltage range is 85VAC to 440VAC, 50/60Hz

But we have few issues-

1.   Start-up issues

2.   If it start up , it turns off  the output at higher voltage  (≈255VAC)

 PNI-UCC28722.pdf

Application Bias power supply for Smart Led Drivers. 

  • 0
    TI__Expert 7395 points
    Dinesh,
    Thanks for your interest in TI here.

    I have a few questions to help us better understand the situation.

    1) Could you share transformer specification? at least turns ratios and primary side magnetizing inductance?

    2) How have you designed the converter? Was this based on a TI reference design? Did you use the excel design tool here?: www.ti.com/.../toolssoftware
    If not, please work through this and provide it back on this post filled in so we can see the individual design decisions you have made in detail.

    3) For general PSR controller debug, please use this resource: www.ti.com/.../slua783.pdf

    Regards,
    John
  • 0 in reply to John Stevens
    Prodigy 60 points

    Hello John,

     Thanks for your  reply.

    1.  Transformer design details are -

     Core EE10/5/5,  N87 from EPCOS

    Primary inductance  ~4mH

    Primary Turns  N1= 280

     Secondary S2/S2= 40/20

    Bias winding = 40 Turns

    2. It was nearly based on TI reference design (PMP10236 RevA) with slight changes. and I  tried the excel design tool, it it ask for the secondary voltage at the beginning , but in my case it is zero. 

    3. Thanks for the PSR controller debug references , I will look into that.

    Please let me know your recomendation for the this design to be functional.

    Best Regards

    Dinesh

  • 0 in reply to Dinesh Kumar41
    TI__Expert 7395 points
    Dinesh,
    Thanks for the details. Can you share the excel design calculator filled out so we can see more details on your design selections and specifications?
    Regards,
    John
  • 0 in reply to John Stevens
    Prodigy 60 points

    Hello John,

    Your documents  www.ti.com/.../slua783.pdf was very useful and we solved the problem.

    Actually we had issue with VS pin voltage divider. we tuned that and both startup and  higher voltage shutdown issues was solved. 

    Thank you so much.

    Best Regards

    Dinesh

  • 0 in reply to Dinesh Kumar41
    TI__Expert 7395 points
    Dinesh,
    Thanks for the follow-up. Glad to hear you can move forward. good luck with the rest of your design!
    Regards,
    John