18v15 High Power Motor Driver - Flyback Diodes?

I tried to search for flyback diodes and I did not find anything that directly answers my question. Are there flyback diodes included on this board?

I did find the following info from user dc42(forum.arduino.cc/index.php?topic=115481.0 -> reply #6):

[quote]If you are using a single mosfet to control a motor, then the body diode of the mosfet is in the wrong position in the circuit to act as a flyback diode, and you definitely need an external one. However, in a mosfet H-bridge configuration, the body diode of each mosfet acts a a flyback diode when the other mosfet in the same half of the H turns off, so you don’t normally need separate flyback diodes.

If you are using PWM and there is a lot of flyback energy coming out of the motor, then a Schottky flyback diode is best, because it will run cooler. Otherwise, use a silicon fast recovery diode. If you are not using PWM, and ordinary silicon rectifier diode is OK.[/quote]

So… the “not normally” is somewhat ambiguous. From the design docs I have been reading they talk about making sure you have the flyback diodes, and this board at first glance does not have them.


There are diodes built into the MOSFETs used in the H-bridge, and you should not need to add an external diode.

- Jeremy