LM5012-Q1: LM5012 inductor is making humming noise

monica bagade

Part Number: LM5012-Q1
Other Parts Discussed in Thread: LM5012

Tool/software:

I have designed Lm5012 circuit for my BMS application for 48V to 12V with rated current of 2A.

Currently, I am testing with power supply of 35V. but inductor is making humming noise even at 10mA load current. I have done schematic as below. I have selected these values based on webench result.

7701.WBDesign8.pdf

Can you please suggest what could be the reason and what should I try?

1. I tried to change Ron (R104) to increase frequency, but not much change

2. I tried to change inductor of 33uH but of compact packing, little bit reduced, but still noise is there.

Thanks,

Monika

7 months ago

0 Nityanand Hegde 7 months ago

TI__Expert 5490 points

Hi Monika,

During light load of operation if the device switching frequency is within audible frequency range, it is expected that audible noise is present in the system. Recommend you to use fully shielded inductor or the ferrite core inductor instead of powered iron core inductor.

Thanks,

Nitya

0 monica bagade 7 months ago in reply to Nityanand Hegde

Prodigy 140 points

Dear Nitya, Thanks a lot for the reply.

Currently I am using 7447709330 which is shielded inductor.

I am going to try below as well.

	74437368220	WE-LHMI SMT Power Inductor
	7447706330	WE-PD SMT Power Inductor
	7447707220	WE-PD SMT Power Inductor
	7447706470	WE-PD SMT Power Inductor

Please suggest if anything else?

Regards,

monika

0 Nityanand Hegde 7 months ago in reply to monica bagade

TI__Expert 5490 points

Hi Monica,

You can try above inductor types and check if the issue is resolved.

Thanks,

Nitya

Power management

Power management forum

LM5012-Q1: LM5012 inductor is making humming noise