DRV8711: question about power supply design for stepper motor driving

Part Number:DRV8711

Hi,

I have a question about power supply design for stepper motor driving:

if I have a stepper motor with 1A coil current and I am using DRV8711 driver to drive the motor. the Max PWM chopping current is set at 1A. Do I need to design a power supply to have VM with 1A output capability? 

the average current of VM is much lower than PWM chopping current. what happens if the VM output current is lower than 1A but higher than average?

Thanks,