sorry i didn't got it your question u means pulse generator IC . but actually we give pulse and direction from micro controller to stepper driver IC like Allegro a3979 , 3977 .
if you want pulse genarator then you can use timer 555 also. u can frequency higher than lower controller. then send to driver and then to stepper motor.
but use of controller for that is good idea bcoz through controller u can controller and adjust the pulses given and to give to driver.