Currently I'm using Arduino UNO R3 board.
I want to drive small DC Motor using same power source as the arduino is using.
My motor driver is TB6612FNG and it works well.
I have two motors.
One is 5V the other is 12V.
So I connect arduino's VIN pin to TB6612FNG's VM(Motor Power) Pins for more voltage to supply 12V motor.
It works good.
But when I connect USB power for 5V motor
then VM voltage is measured under 5V (around 4.4V).
How can I fix it?Is there too much current draw pulling V down to 4.4
Why this voltage appears on VM, and which path is using this voltage?
Any comment appreciated
Thanks
Best Answer
On the Arduino, the 5V supply is the same as the 12V supply EXCEPT it it shunted through the SMT 5V regulator. This 5V regulator is powering nearly everything on board (when USB isn't hooked up), and running a motor on it is a bad idea:
Better solution: You could also PWM the 12V down to 5V. For motors, PWM works very well for 'voltage scaling'. In other words, if you run your 5V motor on 12V and PWM to 42% duty cycle, you have the equivalent of a 5V supply. Your chip has a PWM input, just use that and power both motors from the 12V supply.
Have fun!