Other Parts Discussed in Thread: UCC38C42
Hello guys,
One of our customer is evaluating UCC28C44 on their own AC/DC converter which generates 24V/6A DC from 115V AC input. When their AC/DC converter operates with light loard, burst switching of "OUT" is observed like the attached waveform (Ch2 waveform (Color Pink) is the voltage of photo transistor emitter. Ch3 waveform (Color Blue) is the voltage of UCC28C44 COMP pin. The spike noize timing timing is "OUT" switching timing.) . They can't disclose their board schematic for us but they are using a similar schematic and parts parameter to the application example, Figure 25 on page 22 in UCC28C44 English datasheet.
The customer wants to know whether the burst operation is normal or not. (If we have UCC38C42 EVM, we would check the OUT swiching signal with light load. But we don't have the EVM at the moment.)
If you have the EVM board released by TI, could you check the OUT switching waveform at light loard?
Also if any burst switching is not observed, could you please give me the switching waveform for showing it to the customer and please advice me which part parameter should be changed to reduce the bursting if you have any idea?
Your reply would be appreciated.
Best regards,
Kazuya Nakai.