stm32mp1 external power supply only

[Ara.1]

hi all ,

i have a situation,

1. external supply vdd given to cpu, with application running on it

2. usb-otg is connected from computer to stm32mp1 which provides v5.

3. power off/take off external power supply

ideally unit should be OFF, but CPU is getting supply from PC-computer, has any one have suggestion ?

how to make only power on and off via external board supply only after application running?

[PatrickF]

Hi,

Could you please elaborate a bit more.

Which board are your using ?

If it is STM32MP157x-DK1 or DK2, the board is not supplied when only a computer is connected on OTG (USB Type-C CN7) without any supply on dedicated CN6 connector.

Regards.

[Ara.1]

This is coustom board designed on stm32mp157caa3

usb2 configured as otg its opened as a serial gadget,

When I unplug power to the unit but have USB connected the unit is still powered. some how the unit is getting power from pc,

[PatrickF]

You have to dig into your schematics, your have an unwanted voltage path between your OTG VBUS and STPMIC1 VIN.

That's not linked to STM32MP15x nor SW setting.

Regards.

[Ara.1]

does overcurrent from TPS2051BDGN makes any difference ?

[PatrickF]

I'm sorry, but we cannot answer on your specific HW. It is normally your duty to debug your specific HW you select/assemble based on your requirements.

Do you have followed recommendations on AN5031 or copied some existing schematics from STM32MP157C-DK2 board ?

Did you use STPMIC1 ?

What I can confirm is that STM32MP157C-DK2 and STM32MP157C-EV1 boards are correctly shutdown even when USB is connected to the PC.

Maybe you have to check with the DK2 or EV1 schematics where you missed something on your design around USB OTG connector.