Power supply 5v then 3v is it possible ?

julienterrier39 · ‎2015-09-10

Posted on September 10, 2015 at 15:17

Hello,

I use STM32F429I Discovery-Board to make my project and my question is about power supply available on this board.

I would to know,if it's possible to recover 3V from P2 if I supply the board by an external dc source with 5v on P1 ?

I want to use these 3v to supply an RS232 driver to reach the good logic lvl for USART protocol.

thanks.

Tesla DeLorean · ‎2015-09-10

Posted on September 10, 2015 at 18:30

There is enough head room in the 3V supply/regulator to use the VDD or 3V on the board to power a MAX3232 chip, or a Bluetooth module, or a GPS receiver. I haven't sat and done the math, but I'd expect you have ~50mA to play with.

If you have higher requirements, the 5V gets you close to 500mA via USB, you can add your own regulators or supplies, common the grounds.

If I had a cellular modem wanting 2A peak, I'd use a completely different supply and regulator arrangement.

The boards can also be run off those USB Lithium battery pack/chargers (juice boxes, or whatever you want to call them, $20 at WalMart).

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julienterrier39 · ‎2015-09-11

Posted on September 11, 2015 at 14:28

Hi,

thank you for your answer, If I understood it will depend of current's consumption of my elements.

Anyway I will use an external power supply which can provide higher than 1 or 2 A except that this power supply provide 5V.

I have not made the addition of the current consumed by elements ( Âµcontroleur, LCD, Max3232,Led etc..) but I am sure that my power supply will be effective.