Greetings everyone.

I'd like to build my own PWM controller board for an electric scooter. The controller will probably be made with an Atmel's AVR. It is required for the controller to drive a 24V DC motor (250W).

What bothers me, i went through a lot of literature (http://www.4qd.co.uk/faq/) to find out, how to drive a DC motor (all the MOSFETs, Diodes and that kind of stuff...), and haven't found a suitable circuit. As far as i know, controller can be damaged by the motor, if there is no circuit protection.

So, i would like to know, how do you drive the 24V dc-motor - the circuit starting from pwm TTL output to the part where the motor is connected? How are the MOSFETs connected, capacitors, diodes...? Are optocouplers useful in this kind of situation. Any additional circuits, that could improve the controller?

I would really appreciate some help.

Added after 38 minutes:

This is something interesting i found out: http://www.robot-power.com/products/osmc_info.html - you can find the schematics in the download section.

It looks like it's an H-bridge, so the motor goes both ways (back and forth). How do i modify the circuit (loose the half of the bridge), for the motor to go only in one direction? Is the circuit good enough for an electric scooter?