This is a 4 amp motor driver ckt which i have used in my recent robotics competition ROBOCON where i was driving a power window motor which used to give arnd 25 kgcm torque.
Thinking abt all the financial crisis we had, I choose this ckt which reduces to dig our pocket .
As i have explained in my previous motor driver ckt that there will be two channels in a motor driver IC, each channel giving arnd 1amp in case of l2938d and 2amp in case of l298 . Now i drove both the channels in parallel and hence i was getting 4amp current, this is the most simplest of all motor driver circuits which need more current to drive motors.
W1 and W2 are the inputs, by varying the inputs with 1 and 0 we get different ouputs which drive a motor. Remember to use a heat sink and dont touch it when you turn on the power of it.
The diodes at the motor end are only needed as protective fly back diodes , to protect the motor driver ic , from the current which starts flowing from the motor in back ward direction because of switiching ON and OFF at most of the times. These diodes protect the flow of current to motor driver IC.