• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 260 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.

Original question:

UCC28780: ucc28780- RUN LEVEL AND XMFR RATIO

UCC28780: ucc28780- Ivsl and RUN understanding

robin gangopadhya18
Mastermind 6050 points
Part Number: UCC28780
Other Parts Discussed in Thread: UCC24612

Ulrich:

I think I got it finally: the whole interplay of sws, hvg, ref, run , Ivsl limits , CS limits, output voltage slow start relationship.. etc. in an integrated manner: what I call the "zen"  of it.

So I am going to get the circuit fitted with values from your details & I am sure it will RUN.

We have retested the xmfr(28:3:1)  response, the upper GAN bias  & the lower GaN bias, the secondary response/dc output with 10% load...& know that if PWML happens 1,2, 3,...5 times,  etc.., will continue because of the setup.

Will keep the CS pulled up( with 60k to REF)  until all aspects are checked out & we feel it is ok to go to 380V input.

Will report asap.

thnx so much!

robin

  • 0
    TI__Prodigy 590 points

    Hello,

    Currently Ulrich is not the person who will be assigned questions relating to this part. I have reassigned the thread, and Jaden should be getting back to you shortly,

  • 0 in reply to Pye Naing
    Mastermind 6050 points

    thnx. Expecting to hear from Jaden.

    robin

  • 0 in reply to robin gangopadhya18
    TI__Expert 7080 points

    Hi Robin,

    Could you please share more background information of your design , such as input voltage , output voltage /current  .

    What is symptoms you have seem and the problems . the waveforms you captured

    Please attach the schematic and PCB layout files if it can be published.

    Thanks.

  • 0 in reply to Jaden Ning
    Mastermind 6050 points

    Jaden:A lot has been going on since July!

    As I stated in my last post, Ulrich has the schematic & a section of layout.

    A very short narrative will go like this: we have NV6117 based UCC28780 circuit exactly as the eval kit  sluubv6EVM-021 and we use it to compare. The difference with TI NV6117 eval kit (TIDA-01622) is that we do not use diode drops to power  upper GaN isolator and we have isolator based drive for the lower GaN. We also have EPC2034C as  SR driven by UCC24612.  We have an external 5.2V available. This is used to obtain floating biases for the GaNs.

    If you cannot find the sch, pl give me your email. I will send it again.

    If you need the whole story, I will be a long one!

    But I keep a word file on this. Can send it to you in the email as well.

    Got to state that a whole slew of products using the above devices on ACZVS will be our flagship products. So got to get it fully operating asap.

    So any help will be very much appreciated.

    robin

  • 0 in reply to Jaden Ning
    Mastermind 6050 points

    Jaden

    I missed mentioning input /output

    Input: well regulated from a PFC stage( using Delfino on 3phase input) giving 380V fixed. Very little variation. 

    Single Output products:  from +5v@ 4 amp , -5@10 amp, 12v@5amp, -12v@8 amp, 15V 1 amp, -15V 5 amp, 24V @ 5 amp, 48V @ 3 amp or custom.

    The goal is: smallest footprint highest efficiency, all GaN devices,  UCC28780 UCC24612 chips.

    As to waveforms: so far we only have gottne VDD, HVG, VREF. We did get RUN but as I reported, the controller failed but do not think it produced PWML.

    If we do go up to the min VBULK so that Vcs> min & Ivs >min yet <max, we still do not see RUN .

    All debugging is inspired by the Debug document. Plus our own as I wrote earlier.

    All calculations based upon xl spreadsheet, rev C I got from Ulrich. He has a copy of our calculations.

    Bottom line: why do we not get RUN level go up  & stay ON & get it all working?

    So , we must be missing SOMETHING . & chip failures as I reported.

    -robin

  • 0 in reply to robin gangopadhya18
    TI__Expert 7080 points

    Hi Robin,

    It's a long story !!!  I think E-mail communication is a more effective way , could you please send all of background information to me through E-mail .

    My address is  jaden-ning@ti.com

    So I'll close all of the posts on E2E.

    Thanks.