SLAAEE6 October   2023 MSPM0L1306 , MSPM0L1306

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Hardware Introduction
  6. 3Software Introduction
  7. 4Gauge GUI Introduction
  8. 5Current Detection and Calibration Method
    1. 5.1 MSPM0 OPA Introduction
      1. 5.1.1 OPA input and output limitation
      2. 5.1.2 OPA Accuracy Influence
    2. 5.2 Current Detection Method
    3. 5.3 Current Calibration Method
      1. 5.3.1 (R1+R2)/R2 calibration
      2. 5.3.2 OPA1 Voffset calibration
      3. 5.3.3 R3/(R4+R3) calibration
      4. 5.3.4 Vref calibration
  9. 6Solution Evaluation Steps
    1. 6.1 Step1: Hardware Preparation
    2. 6.2 Step2: Evaluation
  10. 7MSPM0 Gauge Solution Test Results
    1. 7.1 Calibration Test Result
    2. 7.2 Current Detection Result
      1. 7.2.1 Test Under 25°C
      2. 7.2.2 Test Under 0°C
      3. 7.2.3 Test Under 50°C
      4. 7.2.4 Conclusion
    3. 7.3 Current Consumption Test
  11. 8Solution Summery and Improvement Direction
    1. 8.1 Shunter Resistor
    2. 8.2 ADC and its Reference
    3. 8.3 Runtime Calibration

7.2.3 Test Under 50°C

Figure 7-8 shows the current test pattern (left) and the detection error (right) under 50°C and the GAIN factor is gotten at 25°C. In this high temperature, the offset current is same with the one at room temperature. You would assume there is almost no GAIN factor shift.

Under this condition, you can find that this solution can control the error within 11 mA in the range of ±2000 mA. The error is below than ±0.6% at ±2000 mA.

GUID-4A204AD4-4C6E-489C-AA19-CA292750634D-low.png Figure 7-8 Current Test Under 50°C With 25°C Calibration

See what happens when you do GAIN factor calibration under 50°C. You can find that offset current is little reduced. The error reaches to 9.5 mA in the range of ±2000 mA. The error percentage is below than ±0.5% at ±2000 mA.

GUID-121708FE-6094-443C-BA42-7DA505C81E73-low.png Figure 7-9 Current Test Under 50°C With 50°C Calibration