Flyback diode to prevent back voltage

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    Diode Voltage
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Discussion Overview

The discussion revolves around the use of flyback diodes in a motor control circuit, specifically when using the TB6612FNG motor driver to manage two DC motors that can rotate in both directions. Participants explore how to effectively connect diodes to prevent back voltage from damaging the driver when power is terminated.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the need for a flyback diode (1n4001) to protect the motor driver from back voltage when terminating power to the motors.
  • Another participant questions the schematic showing diodes connected from ground to motor terminals, seeking clarification on this configuration.
  • A different participant suggests that using two diodes per motor terminal could limit voltage spikes, provided the components can tolerate slight voltage variations.
  • One participant raises a hypothetical scenario about connecting only four diodes without the additional diodes to ground, prompting a concern about potential voltage spikes damaging the driver.

Areas of Agreement / Disagreement

Participants express differing views on the optimal configuration of diodes, with some proposing specific arrangements while others question the implications of those configurations. The discussion remains unresolved regarding the best approach to connecting the diodes.

Contextual Notes

Participants have not fully explored the implications of using different types of diodes or the specific ratings required for the components involved. There is also uncertainty regarding the exact voltage levels that could be experienced in the circuit.

NATURE.M
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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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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 ??
 
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).
 
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).
 
Then the voltage could spike below ground and damage the driver.
 

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