SLOS825E December 2012 – April 2018 DRV2605
The smart-loop architecture uses actuator feedback by monitoring the back-EMF behavior of the actuator. The level of back-EMF voltage can vary across actuator manufacturers because of the specific actuator construction. Auto calibration compensates for the variation and also performs scaling for the desired actuator according to the specified rated voltage and overdrive clamp-register settings. When auto calibration is performed, a 100% signal level at any of the DRV2605 input interfaces supplies the rated voltage to the actuator at steady-state. The feedback allows the output level to increase above the rated voltage level for automatic overdrive and braking, but without allowing the output level to exceed the programmable overdrive clamp voltage.
In the event where the automatic level-calibration routine fails, the DIAG_RESULT bit in register 0x00 is asserted to flag the problem. Calibration failures are typically fixed by adjusting the registers associated with the automatic level-calibration routine or, for LRA actuators, the registers associated with the automatic-resonance detection engine. See the Automatic-Level Calibration Programming section for automatic-level calibration programming.