How to provide flyback current

[Electronics4you]

Hi there,

When using a H-bridge for a 4A motor together with PWM signalling some flyback current makes the "closed" side of the bridge open (not very much or for long time), but it's not perfect for the MOSFETs in the circuitry. How can a prevent this from happening?

I have reversed biased diodes on the MOSFETs, but I don't know how to do this on the motor when driving it bi-directional.

 

[Optikon]

Hi there,

When using a H-bridge for a 4A motor together with PWM signalling some flyback current makes the "closed" side of the bridge open (not very much or for long time), but it's not perfect for the MOSFETs in the circuitry. How can a prevent this from happening?

I have reversed biased diodes on the MOSFETs, but I don't know how to do this on the motor when driving it bi-directional.

I don't quite understand what you are saying... flyback current? what current? Are you saying that when you close two MOSFETS (to complete the motor path) that the initial current causes your two closed mosfets to open?

 

[Sceadwian]

The current through each leg of the fet only goes in one direction, you just put diodes on every FET. If you're still getting reverse current pulses the recovery time of the diodes you're using isn't good enough.