STM32F4 External 3.6V power

[stefanskos9]

Posted on June 11, 2012 at 09:32

Hi,

I was wondering if I can power the Discovery board via the VDD pins on the headers? I want to use 3.6V rather than the 3V used so I can get a larger more accurate ADC reading (0-3V6 rather than 0-3V). How would this work if I want to program using USB while 3.6V is active? Also, I need the PC to be isolated from the board during debug/programming (ADC will be referenced to 3-phase GND). I was thinking of making an isolated USB cable (as in the following link), will this work? http://www.analog.com/static/imported-files/newsletters/digital_isolation/USB_cable_Nappnote_Rev_d.pdf Thanks for your help in advance.

[frankmeyer9]

Posted on June 11, 2012 at 10:51

I was wondering if I can power the Discovery board via the VDD pins on the headers?

That's certainly possible. It is briefly described in the  user manual of the discovery board. A level of 3.6V should be o.k. four your part, since the F100 are specified up to 4.0V. I did it in a two-stage supply, 5.0V (with a 7805 for some external peripherals) and 3.3V (with a LM317)....so I can get a larger more accurate ADC reading You get a larger range, but not a more accurate reading.

[frankmeyer9]

Posted on June 11, 2012 at 10:51