The application is a small electric vehicle. I am using the DRV8308EVM board, desoldered the output FET's and connected a high current full bridge from Ixys. I am using the DRV8308 in open-loop "Clock PWM Mode" (SPDMODE = 01) because of the quick speed changes of the electric vehicle.
Everything works well (motor running, speed changes, both directions, ...) except that I want to be able to drive a high current (peak 40A) (high torque) when I am starting up the motor. I need this to set the electric vehicle in motion. In this Clock PWM Mode (with MOD120 = 2048) I can see the same duty-cycle on the high side FET's as the input PWM signal. This is expected behaviour explained in the datasheet.
At low speed (low duty-cycle Clock PWM signal) i would like to have a straight forward trapezoidal drive with almost 100%PWM at the high-side FET's, this way i can get the max torque out of the motor. This is now not possible because the link between input PWM and high-side FET's PWM. Is it possible to modify MOD120 register to do this?
Regards,
