transformer design
Hi,
I have a flyback converter that was designed by TOP227. with 24V and 2.5A output.its transformer core is ETD 34/17/11. and it has 5 windings. it has a primary, 2 secondary, an auxiliary.
the two output are parallel in the board , I measured their inductance, both of them are 16 uH with the same diameter wire. I want to know why did the designer make them parallel?
And it has another winding that has the same inductance as primary winding(303 uH) and the same diameter wire as primary. one side of it connect to gnd and another side is not connected.what is this winding?
Best regard,
评论
Hi,
thanks for your reply
I attached transformer diagram.
Best regard,
| Attachment | 大小 |
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| transformer.jpg (81.57 KB) | 81.57 KB |
May I see the actual transformer construction diagram? I may get more information about the secondary winding configuration from this. Thank you.
Regards,
Hi
I don't have transformer construction. I have the board and it's schematic . I don't know how it is winded.
Is there any way to know about transformer construction without unwinding?
Best regard,
Hi!
The NC-to-GND1 winding is used as an EMI shield.
The secondary winding configuration could either be bi-filar or a split secondary depending on how it was wounded. This could be used to improve current capability since your output is 2.5A, improve efficiency, and prevent the skin effect phenomenon.
I hope this helps.
Regards,
Hi,
Many thanks for your help.
So in this case for decreasing skin effect it's better to wind auxiliary or EMI shield between two secondaries .is it true?
Best Regards,
Hi!
Choosing the appropriate wire gauge for winding would help decrease skin effect. Winding the auxiliary in between the two secondaries would be beneficial in terms of the coupling of the transformer.
Regards,
Hi,
thanks a lot for your help.
if power supply is regulated from secondary side it's better to wind auxiliary between primary and secondary. so isn't it better to wind shield between two secondaries?
Best Regards
Hi!
The placement of the shield winding would depend on what you're trying to shield. Usually it is wound closer to the primary in between the secondary winding, that is, if you want to shield the secondary from noise from the primary. The auxiliary winding could be placed in between the two secondary windings to improve coupling.
Regards,
Hi,
Thank you so much for your help.
Best Regards
Hi! May I see the schematic and/or transformer build diagram? I am having a hard time visualizing the concern with regards to the parallel connection at the output and the other windings. Thank you.
Regards,