LM5164: Efficiency calculation at DCM

Junjie Mao

Prodigy 50 points

Part Number: LM5164

Hi team,

I'm a FAE intern, and I'm learning to use the quickstart design tool of ML5164.

I want to know the hiding formula to calculate the efficiency especially at DCM.

And I find that efficiency increases with lower inductor. Can you explain the phenomenon in a formula?

Thanks a lot

Junjie Mao

over 4 years ago

0 Daniel Li14 over 4 years ago

TI__Mastermind 27470 points

Hi Junjie:

when Ton is fixed,low inductor will decrease the frequency in DCM mode. is that a issue for customer?

Thanks

0 Junjie Mao over 4 years ago in reply to Daniel Li14

TI__Prodigy 50 points

Yes, it is a customer issue. Customer feeback says that LM5164 has a low efficiency of 70% when operate @ 12V-5V 50mA.

We need to provide improvement advice.

And I want to know the hiding formula in the quickstart design tool of LM5164. Because the phenomenon that efficiency increases with lower inductor does not match my efficiency derivation formula under DCM. More details will show you through emails.

0 Daniel Li14 over 4 years ago in reply to Junjie Mao

TI__Mastermind 27470 points

HI Junjie:

the datasheet effciency shows it hihger than 90%, so I suggest customer check the EVM and compare the difference between EVM and customer circuit.

Thanks

Power management

Power management forum

LM5164: Efficiency calculation at DCM