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10 years ago.

Is it possibe to power up mbed LPC1768 from 3.3 V source.

Hello,

I want to connect;

i. mbed lpc1768 to Carambola 2 bundle's 3.3 V power rail,

ii Uart ports of the two board.

Is it a good practice to do so?

If possible, can some one tell me mbed side of curent consumption and proper pins?

Sincerely,

1 Answer

John Johnston
9 years, 12 months ago.

I took a quick look at the mbed LPC1768 board schematic. There is not a pin that is intended for this purpose.

If you are good at soldering, you can remove and jumper D2 and remove IC2 and jumper IN to OUT. Remove D1 to prevent inadvertent application of 5 volts to the LPC 1768.

Vin can then be powered by 3.3 V ONLY!!!!. Higher voltages will likely result in a dead mbed. Also, the 3.3 volt output from the mbed (pin 40) will no longer work properly.

You will no longer be able to power the mbed using the USB port. To program, you will need to power the mbed with 3.3 volts.

An alternate solution would be to buy an expensive boost converter to convert the 3.3 volts to 5 volts and power the mbed normally through Vin. You can find small, inexpensive boost converters on Amazon and other places.

Accepted Answer