LM5146-Q1: LM5146-Q1 fails to start under load

Roman Rabkin

Prodigy 10 points

Part Number: LM5146-Q1

Tool/software:

Hello!

I'm using LM5146-Q1 (TI Evaluation Board LM5146-Q1-EVM12V).

I've connected it to 36W (3A) load (electronic load in CW).

The evaluation board falls to start.

Meanwhile it operates perfectly when the load is connected AFTER the LM5146-Q1 started.

Tried to soften the startup - added 1uF capacitor between SS and AGND pins but in vain.

Is it possible to start LM5146-Q1 when already connected to load?

Thanks in advance!

5 months ago

+1 Timothy Hegarty 5 months ago

TI__Guru 73842 points

Hi Roman,

Startup should not be a problem - I suspect current limit is being engaged, especially as you have set constant power. Please measure the output current waveform, as some electronic loads sink an additional current pulse at turn on. Alternatively, you can try a purely resistive load or set the e-load in CC mode.

Regards,

Tim

0 Roman Rabkin 5 months ago in reply to Timothy Hegarty

Prodigy 10 points

Perfectly true.

Replaced e-load with power resistors and the evaluation board returned to function properly.

Many thanks!

0 Timothy Hegarty 5 months ago in reply to Roman Rabkin

TI__Guru 73842 points

Thanks for the question.

Power management

Power management forum

LM5146-Q1: LM5146-Q1 fails to start under load