LM5141QRGEVM: A question about inductor current sensing

Grey Guo

Part Number: LM5141QRGEVM
Other Parts Discussed in Thread: LM5141-Q1

What is the principle of connecting R8, C19 and R7 in parallel?

Why is the sampling of the inductor current achieved by sampling the voltage across C19?

In the datasheet of LM5141-Q1, there is a method called DCR current sensing, but the connection different from that of the EVM.

over 1 year ago

+1 Timothy Hegarty over 1 year ago

TI__Guru 60497 points

Hi Ray,

That RC filter is just to remove any high frequency noise. It's typically only required when the inductor has a low SRF and noise gets across from the SW node to Vout (and thus appears across the shunt). You probably wouldn't need it for inductor current sensing as that provides natural filtering.

Regards,

Tim

0 Grey Guo over 1 year ago in reply to Timothy Hegarty

TI__Prodigy 480 points

Hi Tim,

Thanks for your response. Now I understand how it works.

Best regards,

Ray

0 Timothy Hegarty over 1 year ago in reply to Grey Guo

TI__Guru 60497 points

Thanks for the question, Ray.

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LM5141QRGEVM: A question about inductor current sensing