Bipolar stepper driver

[SR19]

Hi,

Pls find the attached motor datasheet..Im testing bipolar stepper driver circuit which has A4989 driver with IRLR024NPbf Mosfet .. Motor runs smoothly upto 2KHz in full step mode only if step input duty cycle set to below 20% & the current through each coil shows 1.3A. if i increase the duty cycle slightly above 20% ..motor is not rotating properly..How to overcome this problem?

 

[barry]

The pulse width of your step input is irrelevant, as long as you maintain the requirements for minimum high and low time (1uSec). Your problem is somewhere else. Can you post a schematic?

 

[SR19]

Thanks for reply...Here is the schematic