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

5 Current Detection and Calibration Method

Here is the current detection block diagram. We can see that this solution utilizes:

  • Two high precision internal OPAs. One OPA used as a buffer for DAC. Another used to generate gain for the voltage across the shunter resistor.
  • One internal DAC. Used to generate dynamic bias voltage for current detection paired with OPA0.
  • Flexible internal gain, which is the key point to realize different detection range. If you increase the gain, then the detection range will be smaller, but its resolution will be increased as well.
  • Internal SAR ADC. Used to calibrate and detect the voltage output from OPA0.
GUID-A3DE2337-E41F-4568-A301-DA0A3E424AA2-low.png Figure 5-1 Current Detection Block Diagram