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

1 Introduction

The features of this solution are shown below:

  • It supports bi-directional current detection.
  • It can self-calibrate the voltage offset and GAIN setting of the OPA.
  • It can do dynamic GAIN setting to reach high accuracy across low to high current.
  • The detection error at room temperature can reach to ±0.25% at ±2A load.
  • The current consumption can reach 8 μA with 1Hz sample rate.

As this solution is mostly developed for MSPM0 Gauge solution, the following section describes how to detect and test the discharge and charge current of a battery. For other current detection use cases, you can also take this note as a reference.

The solution is combined of three parts. All the software and hardware are reused by MSPM0 Gauge solution. You can find all of them at MSPM0 Current Detection Development package. You can also find the MCU code under the SDK (mspm0_sdk_xxx\examples\nortos\LP_MSPM0L1306\battery_gauge).

  • It is the hardware board that is used to evaluate the current detection solution with MSPM0L130x integrated.
    GUID-85631551-2031-4704-A47C-ACAC4D22DFDE-low.png Figure 1-1 MSPM0 Current Detection Hardware Board
  • It is the software project based on MSPM0L130x.
    GUID-92C5B0F1-C0DB-42F3-9966-C499C48D3F7C-low.png Figure 1-2 MSPM0 Current Detection Software Project
  • It is the GUI. It is written by python, which is mostly used to read the test data from the board.
    GUID-FACBB419-52C4-4018-ADC7-1AF3BEA35548-low.png Figure 1-3 MSPM0 Gauge GUI Project