SLOS854D May 2014 – March 2018 DRV2605L
A key feature of the DRV2605L is the smart-loop architecture which employs actuator feedback control for both ERMs and LRAs. The feedback control desensitizes the input waveform from the motor-response behavior by providing automatic overdrive and automatic braking.
An open-loop haptic system typically drives an overdrive voltage at startup that is higher than the steady-state rated voltage of the actuator to decrease the startup latency of the actuator. Likewise, a braking algorithm must be employed for effective braking. When using an open-loop driver, these behaviors must be contained in the input waveform data.Figure 12 shows how two different ERMs with different startup behaviors (Motor A and Motor B) can both be driven optimally by the smart-loop architecture with a simple input for both motors. The smart-loop architecture works equally well for LRAs with a combination of feedback control and an auto-resonance engine.