Must the primary current Idrain waveform like the ideal waveform in books

Posted by: jinbo on 01/01/2015

Hello!
I use TOP244YN in my product. The primary current Idrain waveform is very different from the waveform in books.
I doubt that is it necessary to make sure the primary current Idrain waveform look like the ideal waveform exactly?

the follow figure 1 is the real waveform in my product .
channel 1 is secondary current ID .
channel 2 is voltage Vds ,
channel 4 is primary current Idrain .

the last figure 2 is the screenshot of " RDR-242 Page 41 ,figure 33"

Files

figure1.jpg (81.7 KB)

figure2.jpg (72.3 KB)

Comments

Thanks for Posting your Question into forum. We appreciate your time and patience.
Could you please send us the procedure how you are measuring the current i.e., Current Probe. The Current waveform measurements in your file doesn't look Correct, they are no way matching the practical current waveforms. We doubt there is really a measurement errors in your waveforms and we recommend to take the measurements again. Also please go through Current measements in Flyback Converter tutorial.

Thanks,
PI-KSAN

Thanks for KSAN 's replay and patience..
I think there is something wrong with measurements.I have posted a correct waveform .
Thanks again.

Thanks for the reply.
we can't download the picture, looks like the naming convention of the image is not working for us.
could you please upload again with different naming with no symbols.

Thanks,
KSAN

I upload a new picture. Is it helpful?

Attachment	Size
ID.jpg (69.04 KB)	69.04 KB

Thanks , This Waveform Looks Perfect and Practical. Looks like you don't have any issue. and your power supply is working in DCM Mode Operation.

Regards,
KSAN