Marco Grossi

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9 years, 9 months ago.

Question about external power supply of STM32L152RE Nucleo Board

I want to power the board from external power supply (battery). From the board data sheet I see there are two ways:

1) Using the Vin pin (7-12V) 2) Using E5V pin (4.75 - 5.25V)

Using the option (1) a 9V battery can be used, while using (2) 4 AA or 4 AAA rechargeble batteries (4x1.2 = 4.8V). The problem with higher voltages I think is related to the LD39050PU33R that generates the +3.3 V power supply and in the data sheet defines an input voltage range from 1.5 to 5.5V with a maximum output current of 500 mA. However in the data sheet it is also specified an absolute maximum input voltage of 7V. Does it mean that the input voltage can be higher than 5.5V if the output current is much lower than 500mA. Do you think the Nucleo Board can be powered with 4 AAA or 4 AA non rechargeble batteries (4x 1.5 = 6V) if the current drawn is not too high (i.e. < 100 mA)?

Thanks.

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