DRV2605L Datasheet, PDF (18/69 Pages) Texas Instruments – DRV2605L 2 to 5.2 V Haptic Driver for LRA and ERM With Effect Library and Smart-Loop Architecture

DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
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8.3.8 Battery Voltage Reporting
During playback, the DRV2605L device provides real-time voltage measurement of the V_DD pin. The VBAT[7:0]
bit located in register 0x21 provides this information.
8.3.9 One-Time Programmable (OTP) Memory for Configuration
The DRV2605L device contains nonvolatile, on-chip, OTP memory for specific configuration parameters. When
written, the DRV2605L device retains the device settings in registers 0x16 through 0x1A including after power
cycling. This retention allows the user to account for small variations in actuator manufacturing from unit to unit
as well as to shorten the device-initialization process for device-specific parameters such as actuator type,
actuator-rated voltage, and other parameters. An additional benefit of OTP is that the DRV2605L memory can be
customized at the device-test level without driving changes in the device software.
8.3.10 Low-Power Standby
Setting the device to standby reduces the idle power consumption without resetting the registers. In this mode,
the DRV2605L device features a fast turnon time when it is requested to play a waveform.
8.3.11 I²C Watchdog Timer
If an I²C stops unexpectedly, the possibility exists for the I²C protocol to remain in a hanged state. To allow for
the recovery of the communication without having to power cycle the device, the DRV2605L device includes an
automatic watchdog timer that resets the I²C protocol without user intervention after 4.33 ms. This behavior
happens in all conditions except in standby mode. If the I²C stops unexpectedly during standby mode, the only
way to recover communication is by power-cycling the device.
8.3.12 Device Protection
8.3.12.1 Thermal Protection
The DRV2605L device has thermal protection that causes the device to shut down if it becomes too hot. In the
event where the thermal protection kicks in, the DRV2605L device asserts a flag (bit OVER_TEMP in register
0x00) to notify the host processor.
8.3.12.2 Overcurrent Protection of the Actuator
If the impedance at the output pin of the DRV2605L device is too low, the device latches the over-current flag
(OC_DETECT bit in register 0x00) and shuts down. The device periodically monitors the status of the short and
remains in this condition until the short is removed. When the short is removed, the DRV2605L device restarts in
the default state.
8.3.12.3 Overcurrent Protection of the Regulator
The DRV2605L device has an internal regulator that powers a portion of the system. If a short occurs at the
output of the REG pin, an internal overcurrent protection circuit is enabled and limits the current.
During a REG short, the device is not functional. When the short is removed, the DRV2605L device automatically
resets to default conditions.
8.3.12.4 Brownout Protection
The DRV2605L device has on-chip brownout protection. When activated, a reset signal is issued that returns the
DRV2605L device to the initial default state. If the regulator voltage V_(REG) goes below the brownout protection
threshold (V_(BOT)) the DRV2605L device automatically shuts down. When V_(REG) returns to the typical output
voltage (1.8 V) the DRV2605L device returns to the initial device state. The brownout protection threshold
(V_(BOT)) is typically at 0.84 V.
The previously described behavior has one exception. The brownout circuit is designed to tolerate fast brownout
conditions as shown by Case 1 in Figure 16. If the V_DD ramp-up rate is slower than 3.6 kV/s, then the device can
fall into an unknown state. In such a situation, to return to the initial default state the device must be power-
cycled with a V_DD ramp-up rate that is faster than 3.6 kV/s.
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