LM5012: Vout drop after increasing the load

Zoey Wu

Expert 5805 points

Part Number: LM5012
Other Parts Discussed in Thread: LM5013

Hi team，

My customer designed a circuit that Vin=48V, Vo=24V, Io=2.5A. And Vo stays normal of 24V when with no load.

But Vo will drop to 18V when increasing the load to 2A. Below is the SW scope in LM5012 @ 2A.

And when they change LM5012 to LM5013, Vo will be a slightly higher than 24V when increasing the load to 2A.

Could u kindly help to explain the possible reason and do u have any advice on the drop of LM5012?

over 2 years ago

0 Marshall_Beck over 2 years ago

TI__Mastermind 35210 points

Hello, for the scope capture provided, what was the Vin voltage?

Additionally, please provide me a schematic for review.

0 Zoey Wu over 2 years ago in reply to Marshall_Beck

TI__Expert 5805 points

Hi Marshall,

u can check the SCH as below. Thanks!

0 Marshall_Beck over 2 years ago in reply to Zoey Wu

TI__Mastermind 35210 points

Hello Zoey what was the Vin voltage?

Reviewing the design, the minimum voltage this design can properly operate at is around 45V.

I would advise them changing R107 to 250kOhm to allow more margin on their design and see if the behavior changes. I can also review their layout if they have that available.

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LM5012: Vout drop after increasing the load