Free wheeling diode

[Roff]

One fine point: If the motor is some distance from the driver, put the diode at the driver, not at the motor. if you put it at the motor, the inductance of the leads can still generate a pretty serious flyback voltage at the driver. You're trying to protect the driver, not the motor (duh!).

 

[dknguyen]

One fine point: If the motor is some distance from the driver, put the diode at the driver, not at the motor. if you put it at the motor, the inductance of the leads can still generate a pretty serious flyback voltage at the driver. You're trying to protect the driver, not the motor (duh!).

Huh, I never thought about that. But then again, the motor is pretty far away from the PCB via wires anyways so it's not exactly easy to stick a diode next to the motor.

 

[Roff]

Huh, I never thought about that. But then again, the motor is pretty far away from the PCB via wires anyways so it's not exactly easy to stick a diode next to the motor.

I only posted that because of this previous post:

You may want a discrete device right at the motor...
Corey

 

[saturn1bguy]

If you put it at the motor, the inductance of the leads can still generate a pretty serious flyback voltage at the driver.

That's a good point about the wiring inductance...
Corey

 

[Pax Writer]

The distance from the PCB to the motor is approximately 5-7cm, and the diode is placed right next to the MOSFET. Ideally I'd like to place the diode on bottom layer right under the MOSFET, but the PCB cannot have components on that side, so it'll sit next to it instead.