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Dear Mr. Spandana,

Mr. Jacob Verschoor is on holiday.

He will be back on 20 august.

Best regards,

Vincent Roorda

Hi Spandana,

I've changed the on delay to 90 ms and the time between re-sequences to 5024 ms, but nothing helps.This doesn't surprise me, because as you can see in the early post there are an critical limit of 10.5ms of the error condition.

When you have other questions or suggestions please let me know.

Best regards, Jacob

Hi Jacob,

I am not sure what the problem is in your case. But let's narrow down the options and get an answer. Can you please try for me the following things:

1) Set the max re-sequences to 4 times in the other config tab.

2) Set the "Vout Under Voltage" fault response to "Do not restart"  in the fault responses and limts tab.

3) Reduce the glitch filter time on Rail4 to 2msec.

Thanks, Spandana

Hi Spandana,

I've tested all three options (single and combined), but nothing helps.

I've found out an other situation, what can possible help you to find out the reason of the problem:

- When rail 11 fails shortly (<10,5 ms, yellow line in the scope image on the post of Feb. 15) Rail 1-7 will be shut down  (line 1-7 in scope image).       OK
- In the meantime rail 11 will be come back. (Rail 11 cannot be shut down).          OK
- Rail 1-7 remains off.                NOT OK  (When rail 11 fails > 10,5 ms Rail 1-7 restart fine)
- When rail 11 fails again for a long time, rail 1-7 turns on      OK, but too late :-)

Thanks, Jacob

Hi Jacob,

It took me a while to setup 11 rails with your settings. I checked on a board here with same settings you had on your rails, fault responses and re-sequencing. Except that I din't have any GPIs/GPOs setup, which anyway I think aren't causing the issue. I somehow had a feeling that the Voltage setpoints you had in your setup are causing the trouble. Some of the Power Good On levels and UV fault limits might not be making the rail attempt to recover from the UV fault.

So I set all rails to one level of UV fault and Power Good on/off and OV fault limits as you can see in the attached project file. The rails are shutting down and ramping up fine on my board. Can you also change all the Voltage margins and limits like I had in the project file and test again. If it works then we can keep modifying the limits for each rail at a time to the level you want them to be. For a quick reference below are the changes I was referring to. You can check the attached project file. My Power supply Voltages are different than yours but you can set the levels in terms of the percentages shown below.

Attached is my project file8880.MyEVMUCD90124A @Forum_Jacob.xml

Thanks, Spandana

Hi Spandana,

I've changed the fault limits, but that has no effect.
I've an other scope picture, with a complete power-cycle sequence (good situation).
If the power-fail on rail 11 too short, all rails will be shut-down fine but comes only up after the first long failure on rail 11.

Earlier scope pictures gives a detail view of the power-down sequence, round the trigger point.

Thanks, Jacob