TIDUEY0A November   2020  – December 2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Li-ion Cell Formation Equipment
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 System Design Theory
      1. 2.2.1 Feedback Controller
      2. 2.2.2 DC/DC Start-Up
      3. 2.2.3 High-Resolution PWM Generation
      4. 2.2.4 Output Inductor and Capacitor Selection
      5. 2.2.5 Current and Voltage Feedback
    3. 2.3 Highlighted Products
      1. 2.3.1 TMS320F28P650DK
      2. 2.3.2 ADS9324
      3. 2.3.3 INA630
      4. 2.3.4 UCC27284
      5. 2.3.5 REF50E
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software
      1. 3.2.1 Opening the Project Inside Code Composer Studio
      2. 3.2.2 Project Structure
      3. 3.2.3 Software Flow Diagram
    3. 3.3 Test Setup
      1. 3.3.1 Hardware Setup to Test Bidirectional Power Flow
      2. 3.3.2 Hardware Setup to Tune the Current and Voltage Loop
      3. 3.3.3 Hardware Setup for Current and Voltage Calibration
      4. 3.3.4 Lab Variables Definitions
      5. 3.3.5 Test Procedure
        1. 3.3.5.1 Lab 1. Open-Loop Current Control Single Phase
          1. 3.3.5.1.1 Setting Software Options for Lab 1
          2. 3.3.5.1.2 Building and Loading the Project and Setting up Debug Environment
          3. 3.3.5.1.3 Running the Code
        2. 3.3.5.2 Lab 2. Closed Loop Current Control Single Channel
          1. 3.3.5.2.1 Setting Software Options for Lab 2
          2. 3.3.5.2.2 Building and Loading the Project and Setting up Debug Environment
          3. 3.3.5.2.3 Run the Code
        3. 3.3.5.3 Lab 3. Open Loop Voltage Control Single Channel
          1. 3.3.5.3.1 Setting Software Options for Lab 3
          2. 3.3.5.3.2 Building and Loading the Project and Setting up Debug Environment
          3. 3.3.5.3.3 Running the Code
        4. 3.3.5.4 Lab 4. Closed Loop Current and Voltage Control Single Channel
          1. 3.3.5.4.1 Setting Software Options for Lab 4
          2. 3.3.5.4.2 Building and Loading the Project and Setting up Debug Environment
          3. 3.3.5.4.3 Running the Code
        5. 3.3.5.5 Lab 5. Closed Loop Current and Voltage Control Four Channels
          1. 3.3.5.5.1 Setting Software Options for Lab 5
          2. 3.3.5.5.2 Building and Loading the Project and Setting up Debug Environment
          3. 3.3.5.5.3 Running the Code
        6. 3.3.5.6 Calibration
    4. 3.4 Test Results
      1. 3.4.1 Current Load Regulation
      2. 3.4.2 Voltage Load Regulation
      3. 3.4.3 Current Linearity Test
      4. 3.4.4 Voltage Loop Linearity Test
      5. 3.4.5 Bidirectional Current Switching Time
      6. 3.4.6 Current Step Response
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author
  12. 6Revision History

2.2.3 High-Resolution PWM Generation

High-resolution PWM achieves high-accuracy feedback control. The high-resolution counter provides 150ps time step capability. For 250kHz switching frequency and 200MHz EPWMCLK, this approach provides approximately 14.7 bits of resolution. Table 2-1 shows PWM resolution at different switching frequencies.

Table 2-1 C2000™ MCU Resolution for PWM and HRPWM
PWM
FREQUENCY		REGULAR RESOLUTION (PWM)HIGH-RESOLUTION PWM
100MHz EPWMCLK
(kHz)BITS%BITS%
2012.30.0218.10
50110.0516.80.001
100100.115.80.002
1509.50.1515.20.003
20090.214.80.004
2508.60.2514.40.005