Hi,
I am trying to create a motor driver circuit using a darlington driver chip with 4x NPN Darlington switches. I believe I know how to accomplish the circuit with 2x NPN and 2x PNP within a chip but is it also possible to do so with 4x NPN switches?
Possible yes (with limited joy).
Recommendable no.
Assuming your motor voltage is 12V, the high side NPN's would need a basis voltage of around 13.5V to conduct properly (which your logic can't deliver).
Besides, Darlingtons have a high voltage drop, so you may end up with around 3V less (than your supply) for the motor.
The chip I currently own is a ULN2064B.
Always post a link to a datasheet when possible - it gives you a better chance of getting useful answers.