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Hi ,
I have an engineer that is trying to program the shut-down sequencing on the UCD90160A (the power up looks good), but all the rails seem to be coming down a the same time.
Is there some other setting that has to be enabled?
Thank you!
-Alberto
Hello
First, I would recommend the attached quick guide so that the engineer can be familiar with the various usages.
1854.UCD90xxx Quick Guide.pptx
Please share the project file from the engineer to better assist?
Regards
Yihe
Hi Yihe,
thanks for sharing.
I will try getting the project file, if I get it I will have to share this in private.
Best regards,
Alberto
Hello
We haven't heard from you for a while and assumed that the issue has been fixed. Please reply if any help is needed.
Regards
Yihe
Hi Yihe,
I have just obtained the project files and shared them with you.
Thank you!
Best regards,
Alberto
Hello
In their project file, the ON_OFF_CONFIG of all rails are set to AUTO(NONE). It means that UCD only power down the rails if rails have fault. But in the project files, none rail has the fault response set to shutdown the rail. So UCD can not shutdown any rail with the settings in the project file. Secondly, some rails have off dependencies and some do not.
There are two ways to control power down
1. controllable approach: application issue OPERATION command or toggle PMBUS_CTRL or toggle GPI(Pin selected rail state) to turn on or off rail purposely. Under this approach, there is no fault reported when the rail is off since the off request is from application.
2. uncontrollable approach: UCD shutdown the rail due to a unexpected rail fault such as OVER/UNDER_VOLTAGE.
It is not clearly what customer want to achieve here.
But in my first reply of the post, I had attached a Quick Guide, please refer this to reconfigure the settings.
Regards
Yihe
Hi Yihe,
thank you , following the procedure helped fix the power down sequencing.
One more question:
There are three auxiliary rails that the UCD doesn't control (but which it is monitoring to sequence the other rails) these are powered up in daisy chain from and derived from the extenal supply.
Will the UCD get stuck in the power down sequence when the unit is powered down but without those rails being disabled?
Could it be continually waiting to complete the sequence? If so, is this a problem?
Can a similar situation affect the power up sequence (I don't think this would be an issue).
Thank you!
Regards,
Alberto
Hi
For the rail that UCD doesn't control, the only thing I can see is that if they are the sequencing off dependencies of other rails, it may prevent the power down of other rails since those aux rails never below POWER_GOOD_OFF threshold due to the control is out of UCD. But if that's the case, customer can enable the Sequencing off timeout action to force disable the rail.
The same applied on the power up sequencing. there is a sequencing on timeout action to force enable the rail.
Regards
Yihe