DRV2624 Datasheet, PDF (16/79 Pages) Texas Instruments – DRV2624 Ultra Low Power Closed-Loop LRA/ERM Haptic Driver with Internal Memory

DRV2624
SLOS893A – DECEMBER 2015 – REVISED DECEMBER 2015
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Feature Description (continued)
8.3.7 Constant Vibration Strength
The DRV2624 device features power-supply feedback. If the supply voltage drifts over time (because of battery
discharge, for example), the vibration strength remains the same as long as enough supply voltage is available to
sustain the required output voltage.
8.3.8 Battery Voltage Reporting
During playback, the DRV2624 device provides cycle-by-cycle voltage measurement of the V_DD pin. The
VBAT[7:0] parameter provides this information.
8.3.9 Ultra Low-Power Shutdown
Setting the device into shutdown state by using the NRST pin reduces the power consumption to sub-micro
levels, allowing the system to preserve power when haptics are not required. In this state, register content is not
preserved.
8.3.10 Automatic Go-To-Stand-by (Low Power)
The DRV2624 automatically goes into a low power standby state when not in use. In this state, register content
is preserved and I²C communication is available. The DRV2624 features a fast turn-on time from standby when
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 DRV2624 device includes an
automatic watchdog timer that resets the I²C protocol without user intervention after 4.33 ms.
8.3.12 Device Protection
The DRV2624 device has integrated protection circuits for thermal and over-current protection, as well as for
UVLO. When such conditions are present, the DRV2624 device will immediately stop playback and go into the
standby state. The respective status bit will be set in register 0x01, which will be cleared upon reagister read. An
interrupt can be fired if the DRV2624 device is configured to do so.
If the critical condition disappears (the over-current condition goes away), the DRV2624 device will proceed with
normal operation, but because the status bits are sticky, they will continue to be asserted until the status register
is read.
8.3.12.1 Thermal Sensor
The DRV2624 has a thermal circuit that immediately puts the device in standby state and sets the OVER_TEMP
bit in the event of an over-temperature condition.
If the interrupt functionality is selected in the TRIG_PIN_FUNC parameter and the interrupt is not masked, and
interrupt will be fired to alert the host processor of a critical condition.
8.3.12.2 Over-Current Protection
During waveform playback, if the impedance at the output pin of the DRV2624 device is too low, the DRV2624
device immediately goes into standby state and latches the over-current flag (OC_DETECT bit).
If the interrupt functionality is selected in the TRIG_PIN_FUNC parameter and the interrupt is not masked, an
interrupt will be fired to alert the host processor of a critical condition.
8.3.12.3 VDD UVLO Protection
The DRV2624 device has a battery monitor that monitors the VDD level to ensure that is above a configurable
threshold (using UVLO_THRES[2:0] parameter).
In the event of a VDD droop, the DRV2624 device immediately goes into standby state to reduce current
consumption and latches the UVLO flag (UVLO bit).
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