Datasheet

DA7280
LRA/ERM Haptic Driver with Multiple Input Triggers,
Integrated Waveform Memory and Wideband Support
Datasheet
Revision 3.0
30-Jul-2019
CFR0011-120-00
16 of 76
© 2019 Dialog Semiconductor
resonance point and achieve the maximum possible actuator acceleration for a set input power, see
Section 5.3 and Section 5.7.1.
I
2
C and PWM Input Streaming
Haptic playback data can be streamed externally either via I
2
C direct register override or from a PWM
data source, see Section 5.2.2. The external input data PWM frequency is independent of the output
PWM signal frequency driven to the actuator. The input PWM signal is low-pass filtered to create a
varying DC level that is the envelope for the drive across the actuator.
Low Latency I
2
C/GPI Wake-Up from IDLE State
The device supports low latency (0.75 ms) wake-up from IDLE state, which is the lowest power state
(typically 0.36 µA from V
DD
). Wake-up is triggered by either GPI or I
2
C activity. I
2
C is fully functional in
all modes including IDLE state and DA7280 retains register settings in all modes, see Section 5.2.1.
Three GPI Sequence Triggers for up to Six Independent Haptic Responses
DA7280 supports up to three GPI inputs which can be used to trigger low-latency playback of up to
six distinct sequences from IDLE state, see Section 5.2.7. Triggering is activated on events caused
by rising or falling edges, or both. The sequence playback is configurable and a GPI can be
associated with either one or two sequences. In the second case, odd events trigger one sequence,
while even events another.
On-Board Waveform Memory with Amplitude, Time, and Frequency Control
DA7280 contains 100 bytes of highly optimized on-board Waveform Memory for user programmable
haptic sequences, see Section 5.8. The Dialog Semiconductor specific format allows control of not
only amplitude and time, but also frequency during the playback of a haptic sequence. This is
specifically intended for use with wideband and dual mode actuators to create a richer user
experience.
Active Acceleration and Rapid Stop for High-Fidelity Haptic Feedback
By measuring and responding to the BEMF of the actuator, DA7280 supports Active Acceleration
which improves actuator response both when increasing and decreasing drive amplitude by
overdriving or underdriving relative to the desired drive level. Similarly, Rapid Stop minimizes the
time needed for the actuator to come to a complete stop by driving against the direction of actuator
movement. These two features enable a high-fidelity haptic response of the actuator and improve on
its inherent physical performance and mechanical time constant, see Section 5.4.
Continuous Actuator Diagnostics and Fault Handling
DA7280 monitors the actuator impedance at the start of each haptic sequence. The value of the
impedance can be read back from a dedicated register, see Section 5.7.3. In addition, impedance,
BEMF, and resonant frequency faults are flagged with automatic shutdown and notification via the
nIRQ pin, see Section 5.6.6.
No Software Requirements with Embedded Operation
The device can function in a stand-alone embedded operation where no host action is needed to
clear generated faults and the device will attempt to drive on each request. This also allows operation
in GPI trigger mode without the need for a host device or host communication, see Section 5.7.7.
Note that initial download of sequences to the device is still required. Once loaded, the Waveform
Memory is retained in all states as long as the supply does not drop below the PoR threshold.
Differential Output Drive
DA7280 includes a full H-bridge differential output PWM drive that has the advantage of maximizing
the power delivered to the LRA from a given supply and allows braking of DC motors by reversing