SLYA036B July   2018  – November 2021 DRV5053 , DRV5053-Q1 , DRV5055 , DRV5055-Q1 , DRV5056 , DRV5056-Q1 , DRV5057 , DRV5057-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Overview
    1. 2.1 Types of Magnetization
    2. 2.2 Types of Magnets
  4. 3Device Descriptions
    1. 3.1 2.5-V to 38-V, Bipolar Hall Effect Sensor Family: DRV5053 and DRV5053-Q1
    2. 3.2 High-Accuracy, 3.3-V or 5-V, Ratiometric, Bipolar Hall Effect Sensor Family: DRV5055 and DRV5055-Q1
    3. 3.3 High-Accuracy, 3.3-V or 5-V, Ratiometric, Unipolar Hall Effect Sensor Family: DRV5056 and DRV5056-Q1
  5. 4Methods
    1. 4.1 Uncalibrated Implementations
      1. 4.1.1 Overview
        1. 4.1.1.1 General Implementation
        2. 4.1.1.2 Preferred Magnet Types
        3. 4.1.1.3 General Accuracy and Resolution
        4. 4.1.1.4 Considerations
      2. 4.1.2 One Bipolar Sensor, Uncalibrated
        1. 4.1.2.1 Specific Implementation
        2. 4.1.2.2 Calculating Region
        3. 4.1.2.3 Accuracy
      3. 4.1.3 Two Bipolar Sensors 90° Apart, Uncalibrated
        1. 4.1.3.1 Specific Implementation
        2. 4.1.3.2 Calculating Region
        3. 4.1.3.3 Accuracy
      4. 4.1.4 Two Bipolar Sensors n° Apart, Uncalibrated
        1. 4.1.4.1 Specific Implementation
        2. 4.1.4.2 Calculating Region
        3. 4.1.4.3 Accuracy
      5. 4.1.5 Three or More Bipolar Sensors, Uncalibrated
        1. 4.1.5.1 Specific Implementation
        2. 4.1.5.2 Calculating Region
        3. 4.1.5.3 Accuracy
    2. 4.2 Peak Calibrated Implementations
      1. 4.2.1 Overview
        1. 4.2.1.1 General Implementation
        2. 4.2.1.2 Preferred Magnet Types
        3. 4.2.1.3 General Accuracy and Resolution
        4. 4.2.1.4 Considerations
      2. 4.2.2 One Bipolar Sensor, Peak Calibrated
        1. 4.2.2.1 Specific Implementation
        2. 4.2.2.2 Calculating Angle
        3. 4.2.2.3 Accuracy
      3. 4.2.3 Two Bipolar Sensors 90° Apart, Peak Calibrated
        1. 4.2.3.1 Specific Implementation
        2. 4.2.3.2 Calculating Angle
        3. 4.2.3.3 Accuracy
    3. 4.3 Lookup Table Calibration Implementations
      1. 4.3.1 Overview
        1. 4.3.1.1 General Implementation
        2. 4.3.1.2 Preferred Magnet Types
        3. 4.3.1.3 General Accuracy and Resolution
        4. 4.3.1.4 Considerations
      2. 4.3.2 One Bipolar Sensor, Lookup Table Calibrated
        1. 4.3.2.1 Specific Implementation
        2. 4.3.2.2 Calculating Angle
        3. 4.3.2.3 Accuracy
      3. 4.3.3 Two Bipolar Sensors ≈ 90° Apart, Lookup Table Calibrated
        1. 4.3.3.1 Specific Implementation
        2. 4.3.3.2 Calculating Angle
        3. 4.3.3.3 Accuracy
    4. 4.4 Peak Calibrated Plus Lookup Table Hybrid
      1. 4.4.1 Overview
        1. 4.4.1.1 General Implementation
        2. 4.4.1.2 Preferred Magnet Types
        3. 4.4.1.3 General Accuracy and Resolution
        4. 4.4.1.4 Considerations
      2. 4.4.2 One Bipolar Sensor, Hybrid Calibrated
        1. 4.4.2.1 Specific implementation
        2. 4.4.2.2 Calculating Angle
        3. 4.4.2.3 Accuracy
      3. 4.4.3 Two Bipolar Sensors 90° Apart, Hybrid Calibrated (Recommended High Accuracy Method)
        1. 4.4.3.1 Specific Implementation
        2. 4.4.3.2 Calculating Angle
        3. 4.4.3.3 Accuracy
  6. 5References
  7. 6Revision History

4.3.1.4 Considerations

  • The magnet does not need to be oriented when using two sensors, and only needs to be roughly oriented when using one sensor because a 0° point can be set during calibration.
  • The sensors and magnet must be placed so that the sensor voltage output is not clipped or railed at either the north or south pole.
  • 0° and 360° are the same angle; therefore, use 0 as ANGLEbelow and 360 as ANGLEabove in Equation 4.
  • Although it is possible to measure voltages that are out of the range of the lookup table (either above the max or below the min recorded voltage values), the absolute min and max values are unknown. Therefore, these measurements are unusable for linear interpolation.
  • The lookup table calibration method can be more difficult to implement when using two sensors than methods that use the arctan2 function for the following reasons:
    • Exceptions must be coded to account for when Vabove – Vbelow ≈ 0 V in order to avoid dividing by 0.
    • Data from the nonlinear regions of each sensor output must be avoided.
    • Calibration data for each sensor must be stored (instead of storing the arctan2 output); therefore:
      • It is harder to determine which calibration region to use because the voltage from each sensor appears in two different regions of the respective lookup tables.
      • It is possible that near a calibration boundary line, the data from each sensor is on either side of that boundary.