UCC28063A: UCC28063A question about interleaving operation,master and slave were not 180 ° shifted waveforms.

HI Bob,

I will look into this and get back to you.

Best Regards,

Ben Lough

Hi Bob,

Could you send me a schematic for this design? I would like to review it.

Best Regards,

Ben  Lough

Hi Bob,

Along with the schematic could you also ask your customer to probe the inductor currents in each phase? It would be good to understand if both phases are still achieving transition mode operation or perhaps one phase is going into DCM while the other is not. Perhaps one of the ZCD signals is getting corrupting and throwing off the timing.

Best Regards,

Ben Lough

Dear Benjamin Lough,

Thank you very much for reply.

I attached file of schematic.
Could you check it?

My customer is measuring inductor current.
I will send you as soon as the waveform arrives.

Best regard.
Bob Lee.

UCC28063A_Question_190910.pdf

Dear Benjamin Lough,

Thank you very much for reply.

I attached file about schematic and waveform.
Could you check it?

Best regard.
Bob Lee.

UCC28063A_Question_Waveform_190910.pdf

Hi Bob,

What I would suggest is go ahead and install a 22pF capacitor between ZCDA and gnd and also between ZCDB and gnd. Check if the behavior improves. I would also suggest checking to see if the probe is impacting the switching timing when a probe is connected to either ZCDA or ZCDB. Try looking at the combined input current with no probes on either ZCD pins and also look at the combined input current when only 1 probe is connected to either ZCDA or ZCDB. Lastly, I would suggest trying to reduce the TSET resistance and see if the interleaving improves.

Best Regards,

Ben Lough

Dear Benjamin Lough,

Thank you very much for your answer.

I reply my customer your answer.
I will feedback my customer situation.

Best regard.
Bob Lee.

Thanks Bob,

Let me know how things look after the changes.

Best Regards,

Ben Lough

Hi Bob,

Did your customer have a chance to try some of the suggestions to address the interleaving issue?

Best Regards,

Ben Lough

Dear Benjamin Lough,

I'm sorry reply late.
I'm confirming my customer situation.

Please wait for my customer the contact.

Best regard.
Bob Lee.

Dear Benjamin Lough,

Thank you very much for reply.

I will contact you if there is progress.

Best regard.
Bob Lee.