SLOS825E December 2012 – April 2018 DRV2605
In closed-loop unidirectional mode, the DRV2605 device provides automatic overdrive and braking for both ERM and LRA actuators. Closed-loop unidirectional mode is the easiest mode to use and understand. Closed-loop unidirectional mode uses the full 8-bit resolution of the driver. Closed-loop unidirectional mode offers the best performance; however, the data format is not physically compatible with the open-loop mode data that can be used in some existing systems
The reference level for steady-state full-scale drive is set by the RATED_VOLTAGE[7:0] bit (when auto-calibration is performed). The output voltage can momentarily exceed the rated voltage for automatic overdrive and braking, but does not exceed the OD_CLAMP[7:0] voltage. Braking occurs automatically based on the input signal when the back-EMF feedback determines that braking is necessary.
Because the system is unidirectional in closed-loop unidirectional mode, only unsigned data should be used. The RTP mode has 8 bits of resolution over the I2C bus. Setting the DATA_FORMAT_RTP bit to 0 (signed) is not recommended for closed-loop unidirectional mode.
The TS2200 library data is stored in bidirectional format and cannot be used in unidirectional mode.
For the RTP interface, set the DATA_FORMAT_RTP bit to 1 (unsigned).