LM5146-Q1: FB-Voltage at only 0.3 V

Stephan Hromecek

Part Number: LM5146-Q1

Tool/software:

Dear all,

the voltage at the Feedback-Pin of my Design (attached below) is always just about 0.3V instead of 0.8V, no matter if there is a load attached or not.
Has anyone else encountered the same issue and if so, what did you do to mitigate it?

Many thannks in advance and kind regards,
Stephan

3 months ago

0 Timothy Hegarty 3 months ago

TI__Guru 67712 points

Hi Stephan,

The schematic is a bit blurry. Also, please send a completed quickstart file for this design https://www.ti.com/tool/LM5145DESIGN-CALC.

PS: I do not recommend using an LC post filter with a voltage-mode controller. Also, no aluminum electrolytic output caps, as the ESR is too high and increases significantly at cold, complicating stability.

Regards,

Tim

0 Stephan Hromecek 2 months ago in reply to Timothy Hegarty

Prodigy 10 points

Hi Timothy, thanks for your quick reply and suggestions and sorry for my late reply.
Attached you find the quickstart file and a hopefully better readable version of my schematic.

Thanks!LM5146-Q1 Quickstart Tool r2 - 24Vin 6Vout 27A 400kHz.xlsm schematic-zugeschnitten.pdf

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LM5146-Q1: FB-Voltage at only 0.3 V