SLVSEE8B November 2019 – May 2021 DRV8899-Q1
In some cases, the full-scale output current may need to be changed between many different values, depending on motor speed and loading. The voltage of the VREF pin can be adjusted in the system to change the full-scale current.
In this mode of operation, as the DAC voltage increases, the full-scale regulation current increases as well. For proper operation, the output of the DAC should not rise above 2.2 V.
The VREF pin can also be adjusted using a PWM signal and low-pass filter. The R-C time constant for the low-pass filter should be longer than 10 times the period of the PWM signal.