Fly-back Diodes

You can use fly-back diodes to create an alternate path for current to flow in a fast switching high-current circuit. However, you must use a fast diode that is rated for the amount of instantaneous current. Typical response time of fast diodes is between 4ns and 40ns. Unfortunately, response time is often reversely propertional to the amount of current a diode can handle.

For an H-bridge, you need four fly-back diodes per H-bridge.