PF3000 lower output voltages - malfunctioning

[pastrana]

Hi everyone,

I have detected a misbehavior on my imx6ul + PF3000 that this behavior only happens sometimes. When the PMIC starts does not put the correct voltage on their outputs (Before loading the u-Boot). It seems like it is on "error mode" because every output is around 0.5v (except Vsnvs). Meanwhile, the inputs voltages are correct, such as Vin ~ 3.6v, Vddio ~ 1.8, Vsnvs ~ 3v and Pwron ~ 2.7v. There are the same values as when it starts successfully and everything works as expected. Therefore, I think that the configuration is correct and I do not know why the PMIC sometimes starts on this "error mode".

As it is said in the data sheet the input voltage range to PMIC is 2.8 V to 4.5 V, or 3.7 V to 5.5 V, PWRON on high voltage is 0.8*Vsnvs-3.6. Therefore, the values are between the specified ranges.

Moreover, when the PMIC came into this "error mode", I can get out of it putting on its Vin 4.4v. Furthermore, other curious characteristic is the current consumption on this "error mode" continues being high, around 110mA at 12v more or less the same as in normal mode.

I have attached the OTP bits configuration if it may be useful.

Have anyone detected something similar before?? Any idea of can I solve it or others parameters to check??

Thanks a lot and regards,

Javi

[pastrana]

Hi everyone,

I continued taking values of the PMIC registers of two different boards, and both give the same values, as you can see below:

There are only two strange things that may be interesting:

The VPWR bit of INETSENSE3 register is set (1), meanwhile the VPWR PMIC input is connected to GND. Because, I am not interested in input voltages higher than 4.5v, therefore I cannot understand why the PMIC is indicating that it is an over voltage.

Following the 6.3.5.1 data sheet section, if the main supply is Vin and it is lower than 4.5v, you can remove the FET MP1 and the VPWR pin to ground, therefore I think that I follow the correct instructions.

This is related to the second strange thing that I found, I am not interested in the LDO low-power mode, but as you can see in the picture, the register LDOGCTL is set (0), it means that the mode is activated. However, I think that it does not have any effect on the PMIC because It has not been installed the proper hardware configuration.

If the Vin receives a voltage peak upper than 4.5v, is it possible that something wrong happens?? I do not have more clues...

Thanks a lot,

Javi.

[igorpadykov]

Hi Javi

according to Table 6. Electrical characteristics – front-end input LDO PF3000 datasheet

VIN max. is 4.55V, so higher voltage may cause device malfunction.

https://www.nxp.com/docs/en/data-sheet/PF3000.pdf 

Best regards
igor

[pastrana]

Hi Igor,

I know, Vin is used to be 3.55v on my board. Do you see anything interesting in the register values??

Thank you,

Javi.

[igorpadykov]

Hi Javi

LDOs can be disabled due to overcurrent, this is described in sect.6.3.10.2
Current limit protection PF3000 datasheet.

https://www.nxp.com/docs/en/data-sheet/PF3000.pdf 

So one can check schematic for possible excessive loads, also one can check STANDBY signal.

Note, one can obtain pf3000&i.MX6UL reference schematic creating service request.

Support|NXP 

Best regards
igor
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[pastrana]

Hi Igor,

First of all, thank you for your quick answer. I am using the default configuration, therefore  following the data sheet the over current limit is disabled. Nonetheless,  I have checked its value asking directly to the device using I2C bus. And the result is the next:

   i2cget -f -y 1 0x08 0x1B

   0x10

Therefore it is only enabled the RESTARTEN bit.

Moreover, I have checked the STANDBY pin during this "error mode" and it does not change, it continue being 0. therefore, I guess that it may be coming in other strange mode. But I do not know what mode... Besides, I can force to go into standby mode, and when I check the PMIC outputs, they keep the same voltages values as in normal mode.

Many thanks,

Javi