UCC28070: 115Vac low frequency output voltage ripple after burn in

shuang qiu

Part Number: UCC28070

Hi,

We used UCC28070 as PF controller, it's found low frequency(4second) output voltage ripple at low line 115Vac after burn in. It disappeared after add 0.5A loading. As the frequency is low, it should not be burst mode.

Please see attached waveforms. At high line 230Vac, we cannot find the low frequency ripple after burn in. Please advise any parameter may cause it, such as compensation loop?

over 6 years ago

0 shuang qiu over 6 years ago

Prodigy 190 points

0 John Griffin1 over 6 years ago in reply to shuang qiu

TI__Mastermind 34465 points

Hi
Please check the recommended component values from the Excel calculator tool.
Check the RSYNTH value and the compensation component values in particular.
It is strange that this issue only happens after burn in.
Usually burn in is a check for manufacturing and soldering quality of the pcb assembly but in your case it seems like some component is being damaged.
Do all your components have the correct temperature range and have you run a temperature profile of the power supply ?

Regards
John

0 John Griffin1 over 6 years ago in reply to John Griffin1

TI__Mastermind 34465 points

Hi,
Since there has been no response in over 2 weeks I will close this post and mark as resolved.
Please open a new post if you have further queries.
Regards
John

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UCC28070: 115Vac low frequency output voltage ripple after burn in