DRV2625 Datasheet, PDF (22/77 Pages) Texas Instruments – DRV2625 Ultra Low Power Closed-Loop LRA/ERM Haptic Driver with Built-In Library

DRV2625
SLOS879A – DECEMBER 2015 – REVISED DECEMBER 2015
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8.5 Operation During Exceptional Conditions
This section lists different exceptional conditions and the ways that the DRV2625 device operates during these
conditions. This section also describes how the device goes into and out of these states.
8.5.1 Operation With No Actuator Attached
In open loop mode, the DRV2625 device will drive the waveform as intended by the user.
In LRA closed-loop mode, if a waveform is played without an actuator connected to the OUT+ and OUT– pins,
the output pins toggle. However, the toggling frequency is not predictable.
In ERM closed-loop mode, the output pins will attempt to drive, however the amplitude is not predictable.
8.5.2 Operation With a Non-Moving Actuator Attached
In the ERM case, the DRV2625 device will attempt to overdrive the actuator until movement is detected.
The model of a non-moving actuator can be simplified as a resistor. If a resistor (with similar loading as an LRA,
such as 25 Ω) is connected across the OUT+ and OUT– pins, and the DRV2625 device is in LRA closed-loop
mode, the output pins toggle at a default f. In LRA open-loop mode the output pins toggle at the specified open-
loop frequency.
8.5.3 Operation With a Short at REG Pin
If the REG pin is shorted to GND, the device turns off. When the short is removed, the device starts in the default
condition.
8.5.4 Operation With a Short at OUT+, OUT–, or Both
During playback, if any of the output pins (OUT+ or OUT–) is shorted to V_DD, GND, or to each other, a current-
protection circuit automatically enables to shut-down the output stage, the OC_DETECT bit is asserted (and an
interrupt is fired if enabled) and the DRV2625 device will go into standby state.
The DRV2625 device only checks for shorts when running a process (either RTP, waveform sequencer,
diagnostics or calibration). If the short occurs when the device is idle, the short is not detected until the device
attempts to run a process.
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