Operation of Ixora with seconds UPS

Dear support team,

We operated the Ixora board on a power supply, which is buffered for about 5 seconds by means of super caps. A power failure is monitored using GPIO. This circuit is intended to ensure that current actual states can be saved safely before shut down. JP1 is set to generate an automatic start when the power returns. This works wonderfully when using the Apalis T30. With the Apalis iMX6, however, the CoM switches off at around 5V. However, if the voltage is then applied again, the iMX6 will not start. Here we found that the voltage at X2/X3 must first drop below 3.3V before the CoM can be restarted.

Do you have an example circuit somewhere of what to do in such a case?

Alternatively, we tested the scenario with a jumper between pin 1 and pin 3 on X5. In this case the descriped behavior doesn’t seem to occur here. However, the question arises whether this would be allowed for continuous operation at all, since pin 3 should actually be supplied with 3.3V and not with 1.9V?

Do you have a recommendation for me? Thanks in advance

Could you please specify you Ixora board HW revision?
Voltage level above 1.8V on X5 pin 3 accepted as a Logic HIGH.

Hello @alex.tx,

We testet that behavior with Ixora V1.1A and V1.2A. We used iMX6Q V1.1B and V1.1D.
Thanks a lot in advance.

Hello JanP,

the IMX6 has a circuit inside which needs to be powered down for a while before switching back on.

Best Regards,
Matthias Gohlke

Hi @JanP,

do you still need help here ?

Best Regards,

Matthias

Hi @matthias.tx,
Many thanks! We found a solution.

Hello @JanP,

if you want a review of your schematic let us know.
We offer a free 30 min hardware design call and a full review on request.

Best Regards,

Matthias

@JanP,

do you still need any help here ?

Best Regards,

Matthias Gohlke