• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 648 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.

LM5060: problem with turn on

user4181921
Prodigy 30 points
Part Number: LM5060

Hi TI E2E,

I use LM5060 at the output of my DC/DC converter. As the load will have either a battery or a load so I want protect converter against reverse polarity. I have a similar schematic to this from figure 41 from datasheet. Output voltage about 12V.  I have problem with turn on LM5060 when my coverter is working. But when I connect external supply to input LM5060 directly, it works properly. I tried to disable UVLO and OVP, change Rs and gate resistor. I do tests either with and without the output load. It very strange for me and I don't have any idea how to repair it. I have two IRFP4468 paralell because I have about 150A on the converter output. I check singnal on gate  and when I have external supply signals looks good, but when I turn on my dc/dc converter I don't have any signal. What should I check? Please give me some advice. Whether it can be related to the noise coming from the dc/dc converter?

Best Regards, 

Grzegorz

  • 0
    TI__Guru* 95751 points
    Hi Grzegorz,

    Welcome to E2E!
    Can you share your complete schematic and test waveforms of LM5060. Please capture by disabling UVLO and OVP (for the time being)
    Vin, Vout, GATE, Iin
    Vin, Vout, GATE, timer voltage

    Best Regards,
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 30 points

    Signals with external supply

    Signals with dc/dc converter

  • 0 in reply to user4181921
    TI__Guru* 95751 points
    Hi,

    Thanks for the test waveforms. It is surprising that 'no GATE' voltage seen in the second case. There are no known issues with the noise for this device.
    What is the peak-peak ripple at the Vin (o/p of the dc/dc converter)? Can you please check by adding more decoupling capacitors to reduce the noise. If it is shareable, can you send schematic of dc/dc stage.

    Best Regards,
    Rakesh
  • 0 in reply to Rakesh
    TI__Guru* 95751 points
    Hello,

    Does adding more decoupling capacitors help anyway?

    Best Regards,
    Rakesh
  • 0 in reply to Rakesh
    Prodigy 30 points
    Hello,

    On Friday I did tests and adding more capacitors (on Vin and Vout) it only helped a bit. It was better, but only to half of my input voltage. Above this voltage (>300V) I still had a problem with turn on gate. But now I know that is a problem with noise and in next version of PCB I try add more capacitors. Or maybe TI have in offer other similar commponent which is less prone to noise?

    Best Regards,
    Grzegorz
  • 0 in reply to user4181921
    TI__Guru* 95751 points
    Hi Grzegorz,

    Thanks for the update.
    At least, I have not heard of such noise sensitivity for the device. Please consider placing low ESR capacitors close to the switching source in the next PCB version.
    Do open a new thread for the follow-up.

    Best Regards,
    Rakesh