STPMIC1APQR does not always turn on.

[vvlad.1]

I have a circuit with pmic STPMIC1APQR and STM32MP157DAA1 processor. For reference, I take STM32MP157A-EV1.

There are cases when STPMIC1APQR does not turn on every time you turn on the power (1 time out of 20-50 turns on). At the same time, the input power of 5V (VIN) is present on it, but there is no output voltage and therefore the processor does not start. When such a situation occurs, only PONKEY_N (PIN 17) helps, then pmic restarts and turns on.

Please help.

I am attaching a schematic and a piece of the pcb.

[Vincenzo]

Dear vvlad. 1,

STPMIC1 has a "AUTOTURNON" feature that run the NVM content for properly turn ON with the right sequence for all the output programmed, this feature is working only at first power supply. Thanks to your schematic, it seem that the 5Vin for the STPMIC1 is coming from LM22678TJ-ADJ 24V-->5V, do you have checked the waveform shape of the 5Vout from LM22678? If the 5V is not stable at the startup and is reaching the Vin_ok threshold of the STPMIC1 more than one time, you lose the AUTOTURNON feature (only for the first time after power on the application), the use of PONKEY_N pin is confirming my idea😊 .

one solution is to program the higher value of the Vin_ok threshold and hysteresis in the NVM content

Let me know

Best Regards

Vincenzo

[PatrickF]

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[vvlad.1]

Your idea seems to work.

I powered the pmic from another power source and the problem went away.

Later I will try to programmatically change VINOK_HYS and VINOK_THRES and tell you if it worked or not.

[vvlad.1 · Accepted solution]

I solved the problem. I replaced the LM22678 chip with the LM22673.

The LM22678 chip did not have a soft start function. Sometimes when connecting, the 5V voltage at the moment of switching on sank and pmic did not turn on.

[SScar.2]

Hi there, 

sorry if I interfere with this old thread. I have a similar problem here... Is there a way to change the "Vin_ok threshold and hysteresis in the NVM content" inside the tf-a code? I need to change this value in the whole distro and I'd like not to write forced i2c commands in userspace, but program the default values inside the tf-a (or u-boot?) instead, or inside the stmpmic driver.  

Thanks a lot