TIDUC07 March   2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 TMAG5170
      2. 2.2.2 DRV5055A4
    3. 2.3 Design Considerations
      1. 2.3.1 Magnet Selection
      2. 2.3.2 Magnet Shape
      3. 2.3.3 Magnet Rotation Speed
      4. 2.3.4 Sensor Location
      5. 2.3.5 Expected Performance
      6. 2.3.6 Layout for Sensor Location
      7. 2.3.7 45° Alignment
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
      1. 3.2.1 Test Equipment
      2. 3.2.2 Test Hardware Configuration
      3. 3.2.3 Test Software Configuration and Initial Data Capture
    3. 3.3 Test Results
      1. 3.3.1 Calibration Methods
      2. 3.3.2 TMAG5170 On-Axis
      3. 3.3.3 TMAG5170 In-Plane
      4. 3.3.4 TMAG5170 Off-Axis
      5. 3.3.5 TMAG5170 45° Alignment
      6. 3.3.6 DRV5055 Off Axis Result
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks

2.3.5 Expected Performance

Based on the simulation results in Figure 2-15, Figure 2-16, and Figure 2-17, it is now possible to estimate any angle error resulting from amplitude mismatch or non-sinusoidal inputs.

  • TMAG5170 Error
    Figure 2-15 Expected TMAG5170 In-Plane Angle Error
    Figure 2-16 Expected TMAG5170 Off-Axis Angle Error
    Figure 2-17 Expected TMAG5170 On-Axis Angle Error
  • DRV5055 Error
    Figure 2-18 Expected DRV5055 Off-Axis Angle Error

    What is evident from each scenario, is that with amplitude correction, each option provides a viable path to design angle encoding. However, each of these cases has assumed ideal mechanical tolerances. Section 3.3 details the actual observed error from each of these device configurations.

    Regardless of the option, input referred noise also impacts overall angle accuracy. As the input SNR ratio varies, the resulting peak noise induced angle error approximately follows the trend in Noise Induced Angle Error. For any sensor used, the required input signal can be calculated based on the angle accuracy requirement.

    Figure 2-19 Noise Induced Angle Error