DRV8307: DRV8307 is not working at Duty cycle below 10%

Part Number:DRV8307

Hello,

I am testing the BLDC motor part no. B773DA3C428D using DRV8307. Its working fine at all duty cycles above around 10%. But at Lower than 10%, it is failed to work. I am not able to understand the issue. PWM frequency was 20KHz. I also tried to increase the PWM frequency so as to check whether there is any minimum Ton required for the IC, but it still shows the same behaviour of not being able to work below 10%. Please guide me to solve this issue. We need this driver to get operated from 0% to 100% with 12-bit resolution i.e. 4096 steps(which is maximum bits available in IC).