My motor driver has died on me for an unknown reason. I had a perfectly working setup and successfully conducted a few motor tests. I use two Pololu 298:1 12V metal gear motors with a Pololu TB6612FNG breakout board and I power the system using a PDB (Diatone V8.3 LC Filter Power PDB Board HUB Low Ripple Current Series). Arduino and TB6612FNG are fed from the 5V BEC and motors from 12V (through the motor driver’s motor pins VMOT, obviously). I’ve purchased the motors and the driver from robotshop.com.
So I had this setup working fine and I was carrying it around in a plastic box. One day I wanted to install it on my robot when I discovered it’s not driving the motors anymore. I double and triple checked the wiring, the solder joints and the Arduino code as well and tested pin outputs using my DMM. I’ve found that A01/A01/B01/B02 do not output anything and a bump has appeared on the chip.
This is a cross-post from the Arduino forum, where I’ve found another user had this exact same problem. I really would like to know what could have happened and how to avoid this in the future?
It looks like that power distribution board you are using has two regulators (a 5V and a 12V regulator) and you are powering the motor driver using the 12V regulator. I only see a single electrolytic capacitor in your system (on the power distribution board) and though it is not clear, it seems like that capacitor might be on the battery input before the two regulators.
DC motors can generate voltage spikes through a motor driver in some modes of operation. With a 12V rail from a switching regulator, a voltage spike like that could push the 12V rail over the 15V absolute maximum for that driver which could produce the type of damage you mention. Adding a few hundred microfarad electrolytic capacitor to the VM supply close to the board should help minimize voltage spikes.
ESD could be an issue if the circuit is loose in a plastic case somewhere.
By the way, some of those ground connections on your motor driver look like they might not be making a reliable connection between the wire and the solder pad. In your case, those ground connections are redundant, but you might perform a fourth check of your connections against the common problems section of the Adafruit Guide to Excellent Soldering, retouch any that seem suspect, and try the circuit one last time.
@nathanb Thank you for the suggestions! So it seems that I have made the wrong choice of hardware component for the task and the circuit works reliably since the TB6612FNG had been replaced by a TB67H420FTG. It is a more robust component and has no problems with voltage spikes while powering from 12V.
