DA9062 brown-out detection

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tentner
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DA9062 brown-out detection

Hi,

I think that the DA9062 does not really supervise the output voltages (and generate a reset in case of a brown-out). Also, the input voltage supervision only asserts after 100ms which is to slow for some brown-out situations. Is this correct?

However, when verifying this behavior with your eval-board and a scope, the 100ms-behavior could be seen at slow brown-outs, however, on faster brown-outs, the nRESET reacted faster than expected from the datasheet. There appears to be another mechanism that reacts faster (e.g. supervision of Vddcore?), but I could not find anything regarding this in the datasheet.

Can you explain this behavior - it would be good to understand if we can rely on this, or if we need an additional external supervisor circuit for reliable brown-out reset.

Thanks,

Thomas

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ED_Dialog
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Hello Thomas,

Hello Thomas,

Sorry for the slow response.

You are correct, the DA9062 does not fully mointor the output voltages of the regulators. The DA9063/63L have built in ADC's for this purpose. On the DA9062 we can use a GreenPAK  to fully mointor the output voltages of each rail. The DA9062 has an LDO output over current and limited over voltage protection feature.  The DA9062 also has internal temperture supervision and Vsys supervision. So for full over-volatge and/or under-voltage protect i would recomend a GreenPAK devices, such as the SLG46620.

https://www.dialog-semiconductor.com/products/slg46620

I will speak to the team about the reaction time of nRESET. How are you testing the brown out?

 

Kind regards,

Elliott

tentner
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Hi Elliott,

Hi Elliott,

I tested this with your eval-board. IIRC I turned the supply voltage down slowly on the bench-top supply and could verify the 100ms delay of the RESET. However, when I simply switched off the supply - the voltage will decay quite quickly (internal C of supply), faster than 100ms, I could still see that a RESET is generated. I am quite sure that you have some additional monitoring for Vsys at ca. 2.5V that operates with no delay. But I have not investigated this in more detail. As we also have a 3.3V supply in the system, this is too low for reliable brown-out detection.

I have added a supply supervisor to Vsys now, that reacts without delay. (Assuming that when Vsys is OK, also the output voltages will be OK.) (I could save this component, if the 100ms delay could be disabled...)

Regards,

Thomas