LMR14050: Vout is dropped with 0.5A load

Hisao Uchikoshi

Genius 14180 points

Part Number: LMR14050

Hi Experts,

My customer is evaluating with below schematics.

Vin : 22Vdc

Vout : 5Vdc

Iout : 5A

As increasing electrical load from 0A, Vout starts to drop with 0.5A or larger load. At 0.56A load, Vout became 13.4V. Vin keeps 22V with this condition.

What is the root cause?

Regards,

Uchikoshi

over 2 years ago

0 Daniel Li14 over 2 years ago

TI__Mastermind 27040 points

HI Hsiao:

can you pls attached SW waveform or customer can try to remove C49 to see any help.

Thanks

0 Hisao Uchikoshi over 2 years ago in reply to Daniel Li14

TI__Genius 14180 points

Hi Daniel,

Thank you for your reply. Even after removing C49, it does not change. Below is SW pin waveform.

From left to right in below figure, load current is 100mA/15V, 0.5A/14.5V, 0.56A/13.2V.

The waveform seems strange. How do you think?

Regards,

Hisao Uchikoshi

+1 Daniel Li14 over 2 years ago in reply to Hisao Uchikoshi

TI__Mastermind 27040 points

HI Hsiao:

22V should be the dc source showing voltage, I think the actual voltage on the PIN is lower than 15V , pls let customer test the PIN voltage , i think it is issue that too large impedance between input source and VIN pin of LMR14050

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LMR14050: Vout is dropped with 0.5A load