LM5143-Q1: audible noise and drop Vout.

Dexter Choi

Part Number: LM5143-Q1

Daer Sir,

When CC mode test, We control Iout load from 0A~21A. It Hear audible noise at 17A load and drop Vout from 12.6V to 10V. And it happen switching lose as below 2^nd capture.

When CV mode test, We control Vout load from 9V ~12.6V. it hear audible noise between 10V~11V of Vout load. And it happen switching lose as below 2^nd capture.

According to the calculation tool, there was no problem of phase margin but does it have some problem on real board ?

How to improve switching lose.

could you let me know any advise.

Test condition

Vin: 12.9V

Vout: 12.6V

Max current: 21A

Yellow: SW1

BLUE: Vin

Green: Iout

Good working up to 16A load.

Yellow: SW1

BLUE: Vin

Green: Iout

Happened switching lose

over 5 years ago

0 Iven Su over 5 years ago

TI__Expert 8245 points

Hi,

Could you please increase input voltage to see if this issue still happens? As the load current increase, the voltage drop in traces are large so it may not support 12.9V to 12.6V out.

0 Dexter Choi over 5 years ago in reply to Iven Su

Expert 2795 points

Dear Iven,

when increase input voltage, this issue still happen.

please let me know any comment.

0 Iven Su over 5 years ago in reply to Dexter Choi

TI__Expert 8245 points

Hi,

Then what's the increased input voltage? Could you please help also probe the switching node in a higher Vin? Thanks.

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LM5143-Q1: audible noise and drop Vout.