LM25069: Manual Reboot Problem

Hung-liang Chen

Prodigy 80 points

Part Number: LM25069

Hi Ti Friends,

I use LM25069 as the hot swap controller equipped a manual reboot circuit.

When I press the button SWT1 to lower the voltage of the PIN_UVLO/EN, LM25069 will off the MOSFET.

Where VDD3V3 is converted by a D-D converter from +5V.

But after that, LM25069 locks and no longer turns on the MOSFET.

Please help me confirm where my lines need to be modified, thank you!

10 months ago

0 Avishek Pal 10 months ago

TI__Mastermind 30915 points

Hi Hung,

Thanks for reaching out. Please share the following waveforms when SWT1 is pressed and released. Make sure to capture all these three signals in a single scope shot.

EN to GND, VIN to GND, and QT1 GATE to GND.

+1 Hung-liang Chen 10 months ago in reply to Avishek Pal

Prodigy 80 points

Hi Pal,

I have solved the problem.

I found the VDD3V3 is converted from +5V. After pressing the SWT1, the VDD3V3 will lower to zero quickly like following figure.
I pull one end of SWT1 to +5V_IN and add a capacitor at +5V_IN. And then it can reboot correctly.

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LM25069: Manual Reboot Problem