Reference power design for USB OTG host AND slave modes

tuomas · ‎2012-03-08

Posted on March 08, 2012 at 16:35

Hi

Does ST have a reference design for an USB OTG use case where e.g STM32F4xx based board could be used both as a USB host providing 5V to the USB device and as a USB slave powering the whole board from the USB's 5v?

Our current design uses TI's TPS2051 (I think ST's STMPS2151 is pretty much the same thing) to control the USB VBUS in a host mode from external 5V and in the slave mode the USB VBUS is connected through a diode to the external 5V. The STM32F4 is powered from the external 5V via a 3.3V regulator.

We are experiencing some weird behavior with the current design and a reference design taking into account this slave/host use case would be very welcomed.

Something like this probably is in the Internet already (not neccessarily from ST) but I haven't just found it yet. So pointers to those would be fine as well.

Thanks.

raffael · ‎2012-03-08

Posted on March 09, 2012 at 08:41

Hello,

On Page 157 of the STM32F405/7 datasheet (Rev2) is a block diagram which probably describes what you are looking for. ''USB controller configured in dual mode...''

Have a look at the Keil mcbstm32f400 boards schematic. It can be powered through USB and can itself power a device:

http://www.keil.com/mcbstm32f400/mcbstm32f400-schematics.pdf

tuomas · ‎2012-03-09

Posted on March 09, 2012 at 17:14

The diagram in the F405 datasheet is a bit too high level but the MCBSTM32F400 looks interesting.

Thanks for the pointers!