Datasheet
Table Of Contents
- General Description
- Key Features
- Applications
- System Diagrams
- Contents
- Figures
- Tables
- Legal
- Product Family
- 1 Terms and Definitions
- 2 Block Diagram
- 3 Pinout
- 4 Characteristics
- 5 Functional Description
- 5.1 Features Description
- Driving LRA and ERM Actuators
- Automatic LRA Resonant Frequency Tracking
- Wideband LRA Support
- I2C and PWM Input Streaming
- Low Latency I2C/GPI Wake-Up from IDLE State
- Three GPI Sequence Triggers for up to Six Independent Haptic Responses
- On-Board Waveform Memory with Amplitude, Time, and Frequency Control
- Active Acceleration and Rapid Stop for High-Fidelity Haptic Feedback
- Continuous Actuator Diagnostics and Fault Handling
- No Software Requirements with Embedded Operation
- Differential Output Drive
- Current Driven System
- Configurable EMI Suppression
- Automatic Short Circuit Protection
- Ultra-Low Power Consumption with State Retention
- Ultra-Low Latency in STANDBY State
- Supply Monitoring, Reporting, and Automatic Output Limiting
- Open- and Closed-Loop Modes
- Open-Loop Sine/Custom Wave Drive Support
- Small Solution Footprint
- Additional Features
- 5.2 Functional Modes
- 5.3 Resonant Frequency Tracking
- 5.4 Active Acceleration and Rapid Stop
- 5.5 Wideband Frequency Control
- 5.6 Device Configuration and Playback
- 5.7 Advanced Operation
- 5.7.1 Frequency Tracking
- 5.7.2 Rapid Stop
- 5.7.3 Initial Impedance Update
- 5.7.4 Amplitude PID
- 5.7.5 Wideband Operation
- 5.7.6 Custom Waveform Operation
- 5.7.7 Embedded Operation
- 5.7.8 Polarity Change Reporting for Half-Period Control in DRO Mode
- 5.7.9 Loop Filter Configuration
- 5.7.10 UVLO Threshold
- 5.7.11 Edge Rate Control
- 5.7.12 Double Output Current Range
- 5.7.13 Supply Monitoring, Reporting, and Automatic Output Limiting
- 5.7.14 BEMF Fault Limit
- 5.7.15 Increasing Impedance Detection Accuracy
- 5.7.16 Frequency Pause during Rapid Stop
- 5.7.17 Frequency Pause during Rapid Stop
- 5.7.18 Coin ERM Operation
- 5.8 Waveform Memory
- 5.9 General Data Format
- 5.10 I2C Control Interface
- 5.1 Features Description
- 6 Register Overview
- 7 Package Information
- 8 Ordering Information
- 9 Application Information
- 10 Layout Guidelines
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
14 of 76
© 2019 Dialog Semiconductor
5 Functional Description
DA7280 is a haptic driver capable of driving both LRA and ERM actuators. The power-optimized
architecture and advanced closed-loop digital algorithms achieve a very high-fidelity haptic drive. It
features frequency control within an onboard Waveform Memory and three distinct GPI inputs, for
triggering up to six distinct sequences. This helps with emulating button pressing in many
applications including gaming, mobile, and wearable devices.
The device controls the level of drive across the load and senses the movement of the actuator. The
driven waveform is generated by a current regulated loop using a high-frequency PWM modulation.
The differential output drive features a switching regulator architecture with H-bridge differential drive
across the load at a frequency of 187.5 kHz. The drive level is based on the sequence from the data
source selected by I
2
C interface, input PWM signal, or Waveform Memory.
DA7280 is capable of closed-loop actuator monitoring while driving to enable calibration-free
playback, frequency tracking (LRA only), Active Acceleration, Rapid Stop, and actuator diagnostics.
Continuous resonant frequency tracking can be enabled while driving an LRA to track the mechanical
resonance of the actuator through closed-loop control. This maximizes electrical to mechanical
energy conversion efficiency for narrowband actuators and is especially useful in applications such
as operating system notifications and alarms.
Resonant frequency tracking can be disabled to operate DA7280 in open-loop wideband frequency
operation while driving LRAs with a wider bandwidth frequency response.
Active Acceleration and Rapid Stop features enable automated driving of both ERM and LRA loads
(when frequency tracking is enabled). This reduces the time to reach the target acceleration level
and the time for the actuator to come to a complete stop.
5.1 Features Description
Driving LRA and ERM Actuators
DA7280 can drive both ERMs and LRAs depending on the register configuration, see Section 5.6.2.
Automatic LRA Resonant Frequency Tracking
LRA resonant frequency shifts over time due to changing operating conditions, such as temperature
or position, and manufacturing spread. LRAs are high-Q systems; if driven at a fixed frequency, the
consequences are loss of electrical to mechanical energy conversion efficiency, weaker than nominal
actuator acceleration output, and significant part-to-part variation in the end-product haptic feel.
Figure 5 illustrates that if the drive frequency is fixed, for example at 200 Hz, frequency variation in
the resonant peak of only 10 Hz can result in a loss of 50 % of the output acceleration.
Frequency [Hz]
Acceleration Output [g]
1
0.5
200 210190
Typical Resonant Peak Variation
(part-to-part, across temperature, drive signal level, and manufacturing lots)
Resonant Peak
with Max Accel.
250150
Figure 5: LRA Output Acceleration Swept in Frequency with Constant Power Input Signal