SLOSE70 December 2020 DRV8434S
The smart tune current regulation schemes are advanced current-regulation control methods compared to traditional fixed off-time current regulation schemes. Smart tune current regulation schemes help the stepper motor driver adjust the decay scheme based on factors such as:
The device provides two different smart tune current regulation modes, named smart tune Dynamic Decay and smart tune Ripple Control.
Smart tune Dynamic Decay greatly simplifies the decay mode selection by automatically configuring the decay mode between slow, mixed, and fast decay. In mixed decay, smart tune dynamically adjusts the fast decay percentage of the total mixed decay time. This feature eliminates motor tuning by automatically determining the best decay setting that results in the lowest ripple for a motor.
The decay mode setting is optimized iteratively each PWM cycle. If the motor current overshoots the target trip level, then the decay mode becomes more aggressive (increases fast decay percentage) on the next cycle to prevent regulation loss. Should a long drive time must occur to reach the target trip level, the decay mode becomes less aggressive (decreases fast decay percentage) on the next cycle to operate with less ripple more efficiently. With decreasing current steps, smart tune Dynamic Decay automatically switches to fast decay to reach the next current step quickly.
Smart tune Dynamic Decay is best suited for applications that require lowest possible current ripple, at the same time maintain a fixed frequency with the current regulation scheme.