TB6612FNG Motor Driver VCC Behavior Explained

Robotics
1

I’ve used the TB6612FNG Motor Driver many times for robots. Each time I’m confused by the VCC pin. The sparkfun hook up guide says that VCC should get 2.7V - 5.5V.

This makes sense, but I have 2 questions:

  1. Why is it that the VCC pin always has some voltage (in my case it’s 1.9V) when VM and STBY are powered? I’m not applying any power to VCC when I check its voltage.

  2. Why do my motors still work properly even when I don’t apply power to VCC? What should happen if VCC isn’t powered? I haven’t noticed any difference (I’m also using PID with the motors so I assume I’d be able to notice something. I tested my robot with VCC On and Off. In both cases, the robot moved relatively straight).

My circuit configuration is similar to the sparfun hookup guide. The exceptions are that I’m using an esp32 and using two power sources instead of one.

2

  1. It shouldn’t be - share a photo/video of you setup/wiring…as of now I’d suspect your 2nd power source is the issue; maybe try a simpler setup instead for testing

  2. Because VM and STBY are all that is required for the motor circuits to be complete