DRV2605L Datasheet, PDF (17/69 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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Edge Trigger
DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
Haptic Waveform
Edge Trigger
Cancellation
Haptic Waveform
Figure 14. Edge Trigger Mode
8.3.5.6.3 Level Trigger
The actions of the GO bit directly follow the IN/TRIG pin. When the IN/TRIG pin is high, the GO bit is high. When
the IN/TRIG pin goes low, the GO bit clears. Therefore, a falling edge cancels the transaction. The level trigger
can implement a GPIO-controlled buzz on-off controller if an appropriately long waveform is selected. The user
must hold the IN/TRIG high for the entire duration of the waveform to complete the effect.
Level Trigger
Haptic Waveform
Level Trigger
Cancellation
Haptic Waveform
Figure 15. Level Trigger Mode
8.3.5.7 Noise Gate Control
When an actuator is driven with an analog or PWM signal, noise in the line can cause the actuator to vibrate
unintentionally. For that reason, the DRV2605L device features a noise gate that filters out any voltage smaller
than a particular threshold. The NG_THRESH[1:0] bit in register 0x1D controls the threshold.
8.3.6 Edge Rate Control
The DRV2605L output driver implements edge rate control (ERC). This control ensures that the rise and fall
characteristics of the output drivers do not emit levels of radiation that could interfere with other circuitry common
in mobile and portable platforms. Because of ERC most system do not require external output filters, capacitors,
or ferrites beads.
8.3.7 Constant Vibration Strength
The DRV2605L PWM input uses a digital level-shifter. Therefore, as long as the input voltage meets the V_IH and
V_IL levels, the vibration strength remains the same even if the digital levels vary. The DRV2605L device also
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.
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