LM5050-1: LM5050 gate signal lost during turn on

Red Yen

Expert 4360 points

Part Number: LM5050-1

Hi Support team

The gate signal from LM5050 controller is short lost during turn on. To cause output voltage dip .

Could you have suggest to fix problem?

condition

Output voltage : 24V

Load condition : 1A (10A max load )

ORING FET : AOT280L

Stand-alone testing (not redundant)

Stand alone test at load 1A & schematic

over 4 years ago

0 Praveen GD over 4 years ago

TI__Guru 57737 points

Hi Red Yen,

In the waveform you shared is CH2 - Gate and is CH-1 input ? Can you please share startup waveform with Vin, Gate and Vout signals.

0 Red Yen over 4 years ago in reply to Praveen GD

TI__Expert 4360 points

Hi Support team

start up waveform

Zoom in

0 Praveen GD over 4 years ago in reply to Red Yen

TI__Guru 57737 points

Hi Red,

Thanks for sharing the waveforms. Let me look into them and get back to you within a couple of days.

0 Praveen GD over 4 years ago in reply to Praveen GD

TI__Guru 57737 points

Hi Red,

Looks like the gate is turned OFF due to glitches on VIN and VOUT.

A voltage difference of -28mV is sufficient between VIN and VOUT for the IC to detect as a reverse current and turn OFF. Capacitors on IN and OUT will help decouple the noise at the input and output which otherwise could trigger false reverse current trips.

So, it is recommended to have capacitors on IN and OUT pins.

Power management

Power management forum

LM5050-1: LM5050 gate signal lost during turn on