PMIC power on issue during start-up

[santhakumara]

Hi, 

  we have designed a system by using iMX 6 solo processor with PMIC MMPF0100.

  which gives an issue during power up.. while giving power to the system for the first time it doesn't booting.

if you give power again within some few seconds it starts booting and functioning properly.

while checking power on sequence during first plug-in we found VDD_HIGH_IN not generated which gets power from PMICs VGEN 6.

Could anyone suggest me what is the issue and relevant workaround.

thanks.

Santhakumar.

[reyes]

Hi Santhakumar,

In case that you are working with a MMPF0100 version of the PMIC (Not the newer MMPF0100A version), then it is possible that you have been affected by the mentioned in the errata ER19 from the errata document: MMPF0100ER

As you can see in this document the workaround consist on add an external components. But as you can also see in the errata document, this issue was corrected on version MMPF0100A of the device, so as Igor properly asked, it’s important to know the full part number of the PMIC.

It’s also important to understand the configuration your connections, for example, is VGEN6 from the PMIC directly connected to VDD_HIGH_IN? Or is also connected somehow to VDD_SNVS_IN? I mention this because there should be a delay for the 1st-time power-on (VSNVS_3V0 is first applied), to ensure 32.768kHz xtal osc output is stable. More information about this case and recommended circuit for the delay can be found in the MCIMX6SX SDB schematic (PSF-27962.pdf) that can be found and downloaded from here. Click on "Printed Circuit Boards and Schematics-Schematics (2)", then download the IMX6SOLOX-SABRESDB-DESIGNFILES.

Have a great day,
Jose Reyes

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[santhakumara]

Hi Jose,

sorry for this huge delay to reply..

we are facing problem as you mentioned in first paragraph.

our device doesn't boot at first time power up. with few seconds if you power it up again it boots. we are not using Coin cell battery instead we are using 3V LDO.

PMIC MPN that we are using is MMPF0100F1AEP and SOC is MCIMX6S5EVM10AC

you were said problem is fixed on this version of PMIC but still we are facing this problem (first time it is not booting)

please help us to get over this.

Regards,

Santhakumar.

[mahi]

Hi Santhakumar,

what is your power supply for the MMPF0100's VIN?

I had a similar issue when I conected VIN to a 3.0V supply missing the fact that the internal state machine of the MMPF0100 needs to see a voltage of at least 3.1V (UVDET threshold) for the transisition from "Coin Cell" to "OFF" state (see Figure 8 and Table 29 of the Datasheet).

When turning off and on again, there was a liitle overshoot on this supply rail which was enough for this transistion.

The datasheet always mentions 2.8 to 4.5V for VIN - but in fact, during powerup VIN has to be 3.1V or more.

Best regards

Martin

[santhakumara]

Hi Martin,

I really appreciate your response..

We have got rid of our PMIC issue. it happened because of our circuit error..

We have found it and got it resolved.

I will get back to you if i have quries.

once again thanks for your response.

We look forward quick responses from this new organization.

regards,

santhakumar.