DRV2605L Datasheet, PDF (29/69 Pages) Texas Instruments – DRV2605L 2 to 5.2 V Haptic Driver for LRA and ERM With Effect Library and Smart-Loop Architecture

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DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
Programming (continued)
8.5.8.1.2 Closed-Loop Mode, Unidirectional
In closed-loop unidirectional mode, the DRV2605L device provides automatic overdrive and braking for both
ERM and LRA devices. This mode is the most easy mode to use and understand. This 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 may 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 this 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 this
mode.
Steady-State
Output Magnitude
Closed Loop, BIDIR_INPUT = 0
RATED_VOLTAGE[7:0]
½ RATED_VOLTAGE[7:0]
Full Braking
Input Interface
PWM
0%
RTP (8-bit) DATA_FORMAT_RTP = 1 0x00
Figure 27.
50%
0x7F
Input
100%
0xFF
NOTE
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).
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