My application uses a lithium battery and a 5V boost IC. I usually use Boarduinos, and I remove the LM7805, and hook my 5V up directly to where the output of the 7805 goes.
Before I ordered, I thought the Arduino Pro Mini from sparkfun didn't have an onboard voltage regulator. I thought it just brought out the ATMEGA Vcc pin. The Arduino Pro Mini specs say input voltage is 5V-12V but will exactly 5V work properly? How much extra power is being dissipated by the onboard voltage regulator?
How much extra power is being dissipated by the onboard voltage regulator?
Nothing - if you bypass it and connect your power source directly to the "Raw" pin.
It is a low drop out regulator, but you still need to feed a volt or so above its rated output voltage. 5V would be ok for the 3V3 version of mini pro, but not so for the 5V version.
Nothing - if you bypass it and connect your power source directly to the "Raw" pin.
Wow, you have made my day. I didn't realize there was a 'raw' pin brought out. So I should just hook my 5V source up there instead of Vcc and leave Vcc empty?
So I should just hook my 5V source up there instead of Vcc and leave Vcc empty?
Yes.
It would also be possible to run either of the boards (mini pro 5V/3V3) directly from a single lithium cell (3V7 nominal). The only difference really is the voltage regulator (which you bypass). This will have implications when you interface to other components (variable Vcc), and this may (or may not) be relevant depending on your project.
It would also be possible to run either of the boards (mini pro 5V/3V3) directly from a single lithium cell (3V7 nominal). The only difference really is the voltage regulator (which you bypass). This will have implications when you interface to other components (variable Vcc), and this may (or may not) be relevant depending on your proj
Unfortunately, my LCD needs 5V, and I can't run JUST the LCD on 5V, or the logic levels wouldn't match the Arduino...sigh....