UCC256303: UCC256303 LATCH issue

Hsu cheng

Part Number: UCC256303

My customer mentioned that there is one 48V/600W secondary side with synchronous rectification UCC256303 will shutdown after booting few minutes.

There are no unnormal wave form deceted durning booting moment.,They figure out that only UCC256303 will LATCH, the other PFC or IC VCC are all

working well. Do you have any idear about what kind of stuation will cause this issue?

over 7 years ago

0 Benjamin Lough over 7 years ago

TI__Mastermind 27135 points

Hi Hsu Cheng,

Thanks for your interest in UCC256303. This IC only has auto-restart fault recovery and should not latch. Is RVCC a stable 12V? What is the behavior of the gate drives during this latch state?

Best Regards,

Ben Lough

0 Paja over 7 years ago in reply to Benjamin Lough

Prodigy 20 points

Dear Ben Lough

My customer has similar problem with UCC256303 in AC/DC 48V/750W application. After some operation time, IC shuts down and appears to be "latched" as this is not followed by an auto-restart procedure. RVCC is stable at 12V, and after "latching" low gate drive is continuously in high state while high gate drive is low.

To verify operation of auto-restart feature, an OVP protection is successfully simulated and IC behaves as expected.

During operation time converter exhibits variation of switching frequency due to PFC output voltage ripple. This is depicted from the resonant current in primary circuit, while operation frequency is in 117kHz range.

Do you have any suggestions what kind of problem will cause this issue?

Best regards,

0 Benjamin Lough over 7 years ago in reply to Paja

TI__Mastermind 27135 points

Hi Paja,

This is likely a layout issue. Could you share your customer's design documents (schematic, layout, transformer spec) with me? You can email them to me directly at ben.lough@ti.com if you do not want to post them on E2E.

Best Regards,
Ben Lough

0 Paja over 7 years ago in reply to Benjamin Lough

Prodigy 20 points

Dear Ben Lough,

I sent you design documents including schematic, layout and transformer description to your email.

Best Regards.

0 Benjamin Lough over 7 years ago in reply to Paja

TI__Mastermind 27135 points

Hi Paja,

Thanks for the documents. I sent you a reply.

Best Regards,
Ben Lough

0 Benjamin Lough over 7 years ago in reply to Benjamin Lough

TI__Mastermind 27135 points

Hi Hsu Cheng,

Were you able to make any progress on this issue?

Best Regards,
Ben Lough

0 Benjamin Lough over 7 years ago in reply to Benjamin Lough

TI__Mastermind 27135 points

Hi Hsu Cheng,

Its been a couple weeks since your last post. I will go ahead and close this thread for now. If you need further assistance with this issue, please feel free to make a new post.

Best Regards,
Ben Lough

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UCC256303: UCC256303 LATCH issue