DRV2605L Datasheet, PDF (16/69 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
www.ti.com
For the LRA, the DRV2605L device automatically tracks the resonance frequency unless the LRA_OPEN_LOOP
bit is set (in register 0x1D). If the LRA_OPEN_LOOP bit is set, the LRA is driven according to the open-loop
frequency set in the OL_LRA_PERIOD[6:0] bit in register 0x20.
8.3.5.4 Analog Input Interface
When the DRV2605L device is in analog-input interface mode, it accepts an analog voltage at the IN/TRIG pin.
The DRV2605L device drives the actuator continuously in this mode until the user sets the device to standby
mode or to enter another interface mode. The reference voltage in this mode is 1.8 V. Therefore, the 1.8 V
reference voltage is interpreted as a 100% input value. A reference voltage of 0.9 V is interpreted as a 50% input
value and a reference voltage of 0 V is interpreted as a 0% input value. The input value in this mode is
analogous to the duty-cycle percentage in PWM mode.
For the LRA, the DRV2605L automatically tracks the resonance frequency unless the LRA_OPEN_LOOP bit is
set (in register 0x1D). If the LRA_OPEN_LOOP bit is set, the LRA is driven according to the open-loop frequency
set in OL_LRA_PERIOD[6:0] bit in register 0x20.
8.3.5.5 Audio-to-Vibe Interface
The DRV2605L device features an audio-to-vibe mode that converts an audio input signal into meaningful haptic
effects using the Immersion audio-to-vibe technology. Audio-to-Vibe mode adds a vibratory bass extension to
portable devices which allows users to feel the audio and visual content. This mode is a key feature because it
allows for existing applications to include haptic sensations without requiring additional software drivers.
Additionally, event-driven audio effects generated within an operating system can be used to automatically
provide a product with haptic sensations. See the Waveform Playback Using Audio-to-Vibe Mode section for
details.
8.3.5.6 Input Trigger Option
The DRV2605L device includes continuous haptic modes (such as PWM and RTP mode) as well as triggered
modes (such as the internal memory interface). The haptic effects in the continuous haptic modes begin as soon
as the device enters the mode and stop when the device goes into standby mode or exits the continuous haptic
mode. For the triggered mode, the DRV2605L device has a variety of trigger options that are explained in this
section.
In these modes, the IN/TRIG pin provides external trigger control of the GO bit, which allows GPIO control to fire
ROM waveforms. This external trigger control can provide improved latencies in systems where a significant
delay exists between the desired effect time and the time a GO command can be sent over the I²C interface.
NOTE
The triggered effect must already be selected to take advantage of the lower latency. This
option works best for accelerating a pre-queued high-priority effect (such as a button
press) or for the repeated firing of the same effect (such as scrolling).
8.3.5.6.1 I²C Trigger
Setting the GO bit (in register 0x0C) launches the waveform. The user can cancel the launching of the waveform
by clearing the GO bit.
8.3.5.6.2 Edge Trigger
A low-to-high transition on the IN/TRIG pin sets the GO bit. The playback sequence indicated in the waveform
sequencer plays as normal. The user can cancel the transaction by clearing the GO bit. An additional low-to-high
transition while the GO bit is high also cancels the transaction which clears and resets the GO bit. Clearing the
trigger pin (high-to-low transition) does nothing so the user can send a short pulse without knowing how long the
waveform is. The pulse width should be at least 1 µs to ensure detection.
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