TIDUEJ8C January   2019  – May 2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 MSPM0G1506
      2. 2.3.2 LMG2100R044
      3. 2.3.3 INA241
      4. 2.3.4 TPSM365
      5. 2.3.5 TMP303
    4. 2.4 System Design Theory
      1. 2.4.1 MPPT Operation
      2. 2.4.2 Buck Converter
        1. 2.4.2.1 Output Inductance
        2. 2.4.2.2 Input Capacitance
      3. 2.4.3 Current Sense Amplifier
        1. 2.4.3.1 Shunt Resistor Selection
        2. 2.4.3.2 Current Measurement Resolution
        3. 2.4.3.3 Shunt Resistor Power Dissipation
      4. 2.4.4 Switching Regulator
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 TIDA-010042
        2. 3.1.1.2 ITECH-IT6724H
        3. 3.1.1.3 Chroma, 63107A
      2. 3.1.2 Software Flow
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Loop Inductances
      2. 4.3.2 Current Sense Amplifiers
      3. 4.3.3 Trace Widths
      4. 4.3.4 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
    7. 4.7 Software Files
  11. 5Related Documentation
    1. 5.1 Trademarks
    2. 5.2 Support Resources
  12. 6About the Author
  13. 7Revision History

2.4.3 Current Sense Amplifier

Table 2-2 Current Sense Amplifier Design Criteria
PARAMETERSPECIFICATION
Maximum common-mode voltage60 V
Maximum input current16 A
Maximum output voltage3.3 V

This reference design requires accurate measurement of the panel and battery currents to calculate and track the maximum power point. The design supports panels of up to 60 V for 24-V battery systems, so a maximum common-mode voltage of at least 60 V is required. The design also requires a negative common-mode voltage to provide function during periods of flyback.

The INA241 is selected for this reference design. The best gain variation must be chosen, as higher gain amplifiers often have increased error and noise parameters, and paired with a shunt resistor that provides high resolution and low power dissipation. Because of the ±0.01% gain error (maximum) and ±1ppm/°C drift, the current sample error is very small. The following equations are used to calculate the resolution of the current sense amplifier and power dissipation of the shunt resistor for the parameters given in Table 2-2, examples follow.