LM3481: LM3481 Flyback SCH Review

Joyce Gao

Part Number: LM3481
Other Parts Discussed in Thread: UC2845, , LM5155

Hi expert,

Customer is designing a Flyback supply solution from UC2845 to LM3481. Now they would like us to help check. I've checked already and there's a connection fault with VDD+. Could you help assign a colleague help check if there any other issues and give some comments? Many thanks!

over 2 years ago

+1 Feng Ji over 2 years ago

TI__Mastermind 22365 points

Hi Joyce,

I cannot find how the output voltage is regulated.

Please refer to LM5155 datasheet for primary regulation or secondary regulation.

Figure 10-10. Secondary-Side Regulated Isolated Flyback
Figure 10-11. Primary-Side Regulated Multiple-Output Isolated Flyback

Best Regards,

Feng Ji

0 Joyce Gao over 2 years ago in reply to Feng Ji

TI__Intellectual 2870 points

Hi Feng,

Appreciate your comments and I think they do mistake FB and COMP. For PS feedback the path should connect to FB pin, and for SS feedback the path should connect to COMP pin, right?

0 Feng Ji over 2 years ago in reply to Joyce Gao

TI__Mastermind 22365 points

Hi Joyce,

You are right.

Best Regards,

Feng Ji

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LM3481: LM3481 Flyback SCH Review