DRV2604L Datasheet, PDF (32/73 Pages) Texas Instruments – DRV2604L 2- to 5.2-V Haptic Driver for LRA and ERM with Internal Memory and Smart-Loop Architecture

DRV2604L
SLOS866D – MAY 2014 – REVISED JUNE 2015
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Programming (continued)
8.5.8.1.2 Closed-Loop Mode, Unidirectional
In closed-loop unidirectional mode, the DRV2604L 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.
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 26.
50%
0x7F
For the RTP interface, set the DATA_FORMAT_RTP bit to 1 (unsigned).
Input
100%
0xFF
32
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