LM5050-2: Gate deactivated for a small period of time, why?

Serghei Plamadeala

Intellectual 450 points

Part Number: LM5050-2

How can prevent deactivate gate command for prevent to broke diode.

1. Can add some filters to prevent deactivation of FET for prevent broke internal diode?

2.To prevent broke LM5050 don't need to command GATE of FET via resistor?

over 4 years ago

0 Karikalan Selvaraj over 4 years ago

TI__Genius 16305 points

In the waveform we see the IN coming after OUT.

To understand better and aid in root cause, can you share the schematic.

Regards,

Kari.

0 Serghei Plamadeala over 4 years ago in reply to Karikalan Selvaraj

Intellectual 450 points

I putted directly on MOS FET.

Vin is the secondary Power supply. Vout is main power supply. I Test the comportment of LM505 how is command to prevent broke internal diode and prevent backward current from Vout to Vin.

0 Serghei Plamadeala over 4 years ago in reply to Karikalan Selvaraj

Intellectual 450 points

Schematic in final should be look like :

SUM 3 supply source in one point.

1 main is battery and 2 secondary is : Voltage from Solar Panels and 1 from Generator Wind.

0 Serghei Plamadeala over 4 years ago in reply to Serghei Plamadeala

Intellectual 450 points

Question is about pull down Resistor and Rgate of MossFet

0 Karikalan Selvaraj over 4 years ago in reply to Serghei Plamadeala

TI__Genius 16305 points

Part of your question is answered in another thread " https://e2e.ti.com/support/power-management/f/196/t/876985"

Pull down resistor of 1Mohm will take away 12uA from 32uA current of GATE (ON) 32uA.

This will slow down turn on.

10ohm resistor from gate of IC to gate of MOSFET can be added. 100ohm is large and will slow down turn off.

Regards,
Kari.

0 Serghei Plamadeala over 4 years ago in reply to Karikalan Selvaraj

Intellectual 450 points

Thanks a lot Karikalan Selvaraj

With lm74700 work more better.

The latest schematic is look like this:

0 Karikalan Selvaraj over 4 years ago in reply to Serghei Plamadeala

TI__Genius 16305 points

Hello Serghei,

Let us know if your question is resolved or if you have more questions on this same topic, post it here.

If you have another question, post another new thread.

If you think your question is answered, click "this resolved my issue" button at the end of the thread.

Regards,

Kari.

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LM5050-2: Gate deactivated for a small period of time, why?