Flyback diode to prevent back voltage

In summary, the conversation discussed the use of a TB6612FNG motor driver and a flyback diode to prevent potential damage to the motor driver from back voltage. The individual was unsure how to connect the diodes to prevent back voltage in a motor that can spin in either direction. They then looked at a schematic and discussed the purpose of connecting diodes from ground to motor terminals, as well as the option of using schottky diodes for protection. It was concluded that not connecting the diodes to ground could result in voltage spikes and damage to the driver.
  • #1
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So I am currently using TB6612FNG motor driver (see https://www.sparkfun.com/products/9457) to drive two dc motors. Now I wanted to connect a flyback diode (1n4001) to prevent any potential damage to the motor driver that may occur from the back voltage of the dc motors after I terminate the power. Normally, if the motor was only running in a single direction it wouldn't be an issue, as I can easily hook up the diode in parallel across the motor. Since I'm controlling a motor that can spin in either direction, I'm not entirely sure how to connect the diodes as to prevent back voltage to the driver. Thanks.
 
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  • #2
So I was looking at this schematic for the diodes http://cdn.instructables.com/FYE/O8QZ/H21CGJYJ/FYEO8QZH21CGJYJ.LARGE.jpg and I'm trying to understand why are diodes connected from ground to motor terminals ??
 
  • #3
You can put in 2 diodes per motor terminal so the voltage won't go much below ground or above the power supply. That will protect the attached components (assuming they can handle the slight rise above the supply or fall below ground). If there is a problem with that, you can use schottky diodes (check leakage and reverse voltage capability).
 
  • #4
What if I hooked up only 4 diodes and did not hook up the 4 diodes connected to ground? (Based on the schematic given above).
 
  • #5
Then the voltage could spike below ground and damage the driver.
 

1. What is a flyback diode and what is its purpose?

A flyback diode is a type of diode that is connected in parallel with an inductive load, such as a motor or solenoid, to prevent back voltage or voltage spikes when the load is turned off. Its purpose is to protect the circuit from potentially damaging high voltage spikes that can occur when the inductive load's magnetic field collapses.

2. How does a flyback diode work?

When the inductive load is turned off, the magnetic field collapses and tries to maintain its current flow. This results in a reverse voltage spike that can damage the circuit. The flyback diode provides a low-resistance path for this reverse current to flow, dissipating the energy and protecting the circuit.

3. What types of circuits require a flyback diode?

Circuits that involve inductive loads, such as motors, solenoids, and relays, require a flyback diode to prevent back voltage. These types of circuits include electronic devices like computers, printers, and appliances.

4. How do I choose the right flyback diode for my circuit?

The right flyback diode for your circuit will depend on the maximum voltage and current of your inductive load. You will need to choose a diode with a voltage rating higher than the maximum voltage of your load and a current rating higher than the maximum current of your load.

5. Can I use a regular diode instead of a flyback diode?

No, a regular diode is not designed to handle the high voltage spikes and reverse currents that occur in circuits with inductive loads. Using a regular diode in place of a flyback diode can result in damage to the circuit and potentially cause failure of the load.

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