Why Your TB6612FNG Isn’t Driving Motors Correctly

Why Your TB6612FNG Isn’t Driving Motors Correctly: Troubleshooting and Solutions

The TB6612FNG motor driver is widely used in robotics and electronics projects due to its ability to drive DC motors and stepper motors. However, there are times when users face issues with the motor not functioning correctly. Let's break down the possible reasons behind this problem and provide a step-by-step guide on how to solve it.

Common Causes of the Problem

1. Incorrect Wiring or Connections Cause: One of the most common issues is improper wiring. If the connections to the TB6612FNG are incorrect, the motor will not operate as expected. Solution: Double-check all your connections. Ensure the following: Motor pins (A1, A2, B1, B2) are connected properly to the motor terminals. VM (motor voltage) and VCC (logic voltage) are connected to the correct Power supply. Ensure that the GND is properly connected to both the motor and the logic circuit. The PWMA and PWMB pins are connected to the PWM control signal for speed control. 2. Insufficient Power Supply Cause: The TB6612FNG requires a specific voltage and current to operate properly. If the power supply is insufficient or unstable, it can cause the motor to behave erratically or fail to start. Solution: Make sure the power supply matches the requirements of both the motor and the TB6612FNG driver: The VM pin should have a voltage suitable for your motor (usually 4.5V to 13.5V for most DC motors). The VCC should be between 2.5V to 5.5V to power the logic side of the driver. Verify that your power supply can handle the current required by both the motor and the driver without dropping voltage or overheating. 3. Faulty PWM Signal Cause: The TB6612FNG motor driver uses PWM (Pulse Width Modulation) to control motor speed. If the PWM signal is faulty, the motor won’t run at the correct speed or might not run at all. Solution: Ensure that the PWM signals on PWMA and PWMB are generated properly by your microcontroller or driver circuit. If you're using an Arduino or similar microcontroller, check the code and verify the PWM pins are correctly configured. Use an oscilloscope or a logic analyzer to check if the PWM signal is reaching the TB6612FNG as expected. 4. Overheating or Thermal Shutdown Cause: The TB6612FNG includes over-temperature protection. If the chip gets too hot, it will automatically shut down to prevent damage, causing the motor to stop. Solution: Ensure proper heat dissipation. If necessary, add a heatsink to the TB6612FNG. Reduce the current drawn by the motor by using motors with lower current requirements or ensuring the motor is not overloading. Make sure your power supply is not providing excessive current to the motor, which could lead to overheating. 5. Faulty TB6612FNG Chip Cause: In some rare cases, the TB6612FNG itself could be damaged or faulty. Solution: If all other troubleshooting steps fail, it might be necessary to replace the TB6612FNG chip. Check if the driver IC is getting too hot or if you observe signs of physical damage. 6. Incorrect Logic Levels Cause: If the logic voltage (VCC) is outside the recommended range or incompatible with the logic level of the microcontroller or other control devices, the TB6612FNG may not function correctly. Solution: Ensure the VCC voltage is in the proper range (2.5V to 5.5V). If you're using a 3.3V logic system, ensure that the TB6612FNG's inputs can accept 3.3V signals (most of the time, it can, but it’s good to verify).

Step-by-Step Troubleshooting Guide

Check All Connections: Revisit your wiring to ensure all pins are connected correctly. Pay special attention to motor connections and the power supply. Verify Power Supply: Double-check the voltage levels on the VM and VCC pins to ensure they are within the recommended ranges. Check the current capabilities of your power supply to ensure it can handle the motor's requirements. Test PWM Signal: Verify that the PWM signals are being generated correctly. Use an oscilloscope or a multimeter with frequency measurement to check the PWM signals on PWMA and PWMB. Check for Overheating: Touch the TB6612FNG (carefully, it might be hot) to see if it’s overheating. Ensure proper ventilation and heat dissipation. Test the Motor: Test the motor with another driver to confirm that the motor is not faulty. Replace the Driver: If all other checks are fine but the motor still doesn't work, consider replacing the TB6612FNG to rule out a faulty chip.

Final Thoughts

By following these steps systematically, you should be able to identify and fix the issue with your TB6612FNG motor driver. Start with checking the wiring and power supply, then move on to verifying the PWM signal, and ensure there’s no overheating. If nothing works, replacing the motor driver might be the best option. Troubleshooting such issues can be time-consuming, but with patience, you’ll get your motor running smoothly again!