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LM3421-Q1: output triggering during startup

Part Number: LM3421-Q1

Hi,

I am using in a board the Boost driver circuit of the schematic showed here: https://1drv.ms/i/s!AhE6En32rx-MoJxQAjgxhmwvcS-G8w?e=F6BLIm There are two identical drivers sharing Vsystem bus. 

It is working fine but when I turn ON the device all LED turn ON for a short period of time and after that turn OFF. This is an undesirable effect for this kind of device. 

I saved some waveforms:

waveform Vin x Vddrv(green):

 

waveform VGateQ3 x Vddrv(green):

waveform Vcomp x Vddrv(green):

waveform Vndim x Vddrv(green):

I would appreciate your suggestions about how to correct this problem.

thank you.

Ubiratan