I've burned 3 teensy 4.1s, now I want to make sure it never happens again

[General_Hex]

Hi,

Within the past two days I have burned two teensy 4.1s with a third one being burned months ago. The one burned ages ago I know why they burned (because a pin received more than 3V) however the two that were burned within the last two days I am still unsure as to the reason.

I am currently working on a robot project where the teensy is in this circuit on a bread board (sorry I do not have any photos as I do not have access to the robot right now and I do not have a schematic):

the main power source for the entire robot is a 12V battery which directly powers 4 12V DC motors. Then a wire from the 12V line goes to a voltage step down which decreases the voltage to around 4.7V which is then used to power the Teensy.


The teensy's 3V pin is connected to a power line which is used to power:

• IMU (Gyro Sensor)
• 3 ultrasonic sensors
• IR Sensor (its a Building Blocks robotics IR sensor)

Connected to the teensy's other pins are:

• PWM wire for each of the 4 motors
• Direction wire for each of the 4 motors
• I2C connection for IR sensor
• I2C connection for IMU
• Wire connected to switch connected to 3V line used for code (stopping and starting robot without turning off robot)

All ground wires of all components including Teensy are connected to the same ground line.
Motors have built in encoders.

I am tired of these expensive teensy's burning especially for reasons we still do not know, so I want to implement a new circuit to fully protect the teensy. The current plan is this:

1. Place one Diode (1A rated) on all motors' ground and power to protect teensy from reverse pulse
2. Place Diode (1A rated) on the VIN pin of the teensy to protect from reverse polarisation
3. Place 150mA fast burn Fuse on the VIN of the teensy to protect from high current

My questions are these:

1. Would all these methods work to protect the teensy?
2. Is this overkill? if yes then how much would I need to do to ensure the teensy doesn't burn?
3. is there anything else I can do to further protect the teensy?

Notes:

• I am a high school student new to electronics and teensys so please try to explain things in simple terms as I might not understand or know
• I can send the exact links of the components or specs of the components if that would help
• We are on a tight schedule as we have a State competition this weekend and if we cannot get something quickly or in store we are unlikely to be able to get it
• if there is any further information that would help please let me know
• the voltage step down already has a diode to protect it from reverse current (2A diode)

 

[kd5rxt-mark]

@General_Hex: Starting additional threads on the same subject is discouraged (doing so does not increase the likelihood of an answer, and more importantly, doing so makes it harder for others that may have the same question/problem as you to find/follow the discussion in the future). For the best support, you should continue the discussion on your <original thread>.

 

[General_Hex]

Appologies but this thread is different because in my other thread my intention was to solve the issue with the teensy 4.1 flashing and in this thread I am trying to solve a seperate issue of ensuring no more teensys are burned (i.e how to ensure it doesn't happen again) which is why I thought it was appropriate to start a new thread.