UCC28070: Abnormal current waveform of UCC28070

Feng bin Su

Expert 8760 points

Part Number: UCC28070

Hi team,

My customer has used our UCC28070 to implement their pfc circuit.

They have faced some abnormal waveform of UCC28070.

The application specification :

Vac=120v, fs=50kHz, Pout=1200W

Ch1, Ch2: 2-phase current waveform, Ch3: phase1 gate voltage

Would like to consult with you the reason to induce this abnormal waveform happened?

My customer also mentioned that there is chance to burn out the power mosfet.

Is it possible to related with the abnormal waveform? Thanks.

over 6 years ago

0 David Huang33 over 6 years ago

TI__Genius 9140 points

Hi Mr Su，

can you offer me more information about the phenomenon？

1：does the abnormal always happen at the peak region of the line voltage?

2: whether reducing the output load, the abnormal disappear?

3:whether the abnormal always happen at a constant condition?

can you double check whether the waveform on UCC28070 Pin GDA/GDB is the same as Mosfet?

can you help try RDM pin connect directly to pin 15?

can you help try R13 Ground side connect directly to pin15?

thanks.

0 David Huang33 over 6 years ago in reply to David Huang33

TI__Genius 9140 points

Hi Mr Su:

are you still looking at this issue? Can you update the information I need?

0 David Huang33 over 6 years ago in reply to David Huang33

TI__Genius 9140 points

Hi Mr Su:

From your schematic, I can not find the current sampling part, can you send me the total schematic? thanks.

Wenbin

0 Feng bin Su over 6 years ago in reply to David Huang33

TI__Expert 8760 points

Hi Webin,

Sorry. I am still waiting the customer feedback about it.

Please refer the below figure for it.

0 David Huang33 over 6 years ago in reply to Feng bin Su

TI__Genius 9140 points

Hi Su：

From your current sampling circuit, customer still use CT for current sampling. Since CT has inductor on the primary side, this inductor may influence the PFC mosfet VGS. I would suggest move the CT on the tope side of Mos Drain which is also recommended by TI.

please help work with customer and feedback the result and the information I need to me, thanks a lot.

0 David Huang33 over 6 years ago in reply to David Huang33

TI__Genius 9140 points

Hi Su:

since there still do not have any information or update from customer, can you keep pushing customer for the update?

Only in this way we can support.

any post has time limited, I suggest we can change the discussion from e2e to email. So can you send updates to me through email:wenbin-huang@ti.com

thanks so much.

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UCC28070: Abnormal current waveform of UCC28070