LM5022: EMI issue

Jerry Hsueh

Expert 2730 points

Part Number: LM5022

Hi TI

In order to solve EMI

After replacing R4974 with 0 ohms, EMI improved, but 15W and 30W still failed.

Do you have any suggestions?

In order to solve EMI

We changed R4974 to 0 ohms, but we are not sure if there are any side effects of this change.

SCH and TX SPEC are as below.H12-PW07212ST EFD20.pdf

over 5 years ago

0 Jerry Hsueh over 5 years ago

Expert 2730 points

Jerry

0 Jerry Hsueh over 5 years ago

Expert 2730 points

Jerry

0 Jerry Hsueh over 5 years ago

Expert 2730 points

Jerry

0 Jerry Hsueh over 5 years ago

Expert 2730 points

Jerry

0 Youhao Xi over 5 years ago in reply to Jerry Hsueh

TI__Guru* 75915 points

Hi Jerry,

Thank you for designing with the LM5022. You posted the schematic 4 times, is there a special meaning?

You should not make the current sense resistor 0 ohm. The LM5022 is a current mode control device, and the proper control scheme depends on the current signal.

Can you show us the EMI results before the current sense resistor was changed to 0 Ohm? Also, are these radiated or conducted emissions?

Thanks,

Youhao Xi, Applications Engineering

0 Youhao Xi over 5 years ago in reply to Youhao Xi

TI__Guru* 75915 points

Hi Jerry,

Can I assume the issue is resolved? Let me close it here but you can re-open it by adding a new post. If you have any updates, please let us known.

Thanks,

Youhao

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LM5022: EMI issue