SLOU432B December   2015  – December 2021 DRV2625

 

  1. 1 Getting Started
    1. 1.1 Evaluation Module Operating Parameters
    2. 1.2 Quick Start Board Setup
  2. 2 DRV2625 Demonstration Program
    1. 2.1 Modes and Effects Table
    2. 2.2 Description of the Demo Modes
      1. 2.2.1 Mode Off – Haptics Effect Sequences
      2. 2.2.2 Mode 4 – ERM Clicks
      3. 2.2.3 Automatic Braking in Open Loop
      4. 2.2.4 Auto-Resonance Tracking
    3. 2.3 ROM Library Mode
    4. 2.4 Waveform Library Effects List
  3. 3 Additional Hardware Modes
    1. 3.1 Accessing GUI Mode
    2. 3.2 Accessing Bluetooth Mode
    3. 3.3 Haptics Control Console GUI
      1. 3.3.1 DRV2625 Console
  4. 4 Hardware Configuration
    1. 4.1 Input and Output Overview
    2. 4.2 Power Supply Selection
    3. 4.3 Using an External Actuator
    4. 4.4 PWM Input
    5. 4.5 External Trigger Control
      1. 4.5.1 MSP430 Trigger Control
      2. 4.5.2 External Source Trigger Control
    6. 4.6 External I2C Input
      1. 4.6.1 External I2C Control Initialization
    7. 4.7 Analog Input
  5. 5 Measurement and Analysis
    1. 5.1 Using Low-Pass Filter to Record Waveforms
  6. 6 Modifying or Reprogramming the Firmware
    1. 6.1 MSP430 Pin-Out
  7. 7 Schematic
  8. 8 Layout
  9. 9 Bill of Materials
  10. 10Revision History
  11. 11Trademarks

2.2.4 Auto-Resonance Tracking

Figure 2-9 and Figure 2-10 below showcase the advantages of the Smart Loop Architecture which includes auto-resonance tracking, automatic overdrive, and automatic braking. The two images below show the difference in acceleration between LRA auto-resonance ON and LRA auto-resonance OFF. Notice that the acceleration is higher when driven at the resonant frequency. The auto-resonance ON waveform has 1.32 G of acceleration and the auto-resonance OFF waveform has 0.92 G of acceleration. The auto-resonance ON waveform has 43% more acceleration.

GUID-139216D3-4D4E-4BEF-B98A-6926A9938643-low.gifFigure 2-9 LRA Auto-Resonance ON Waveform (Button 1)
GUID-8E5D7ADB-B64C-4F5C-BC13-296788CCF2D1-low.gifFigure 2-10 LRA Auto-Resonance OFF Waveform (Button 2)

The reason for higher acceleration can be seen in the acceleration versus frequency graph below. The LRA has a very narrow operating frequency range due to the properties of a spring-mass system. Furthermore, the resonance frequency drifts over various conditions such as temperature and drive voltage. With the Smart Loop auto-resonance feature, the DRV2625 dynamically tracks the exact resonant frequency to maximize the vibration force.

GUID-5CCAACC7-7F60-43B0-9C10-2D5227A21120-low.pngFigure 2-11 Acceleration Versus Frequency