TIDUFC9 May   2025

 

  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
      1. 2.2.1 Codec Design
      2. 2.2.2 Class-D Amplifier
        1. 2.2.2.1 Audio Filter Design
      3. 2.2.3 Power Design
      4. 2.2.4 EMC, EMI Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TAC5312-Q1
      2. 2.3.2 TAS5441-Q1
      3. 2.3.3 LMR43620-Q1
      4. 2.3.4 TPS7A52-Q1
      5. 2.3.5 TPD2E007
  9. 3Hardware, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 Board Connection
      2. 3.1.2 Configuring the Board
    2. 3.2 Software Requirements
      1. 3.2.1 Firmware for Bench Tests
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Audio Performance
      2. 3.4.2 Power Tests
      3. 3.4.3 EMI, EMC Test Results
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 Bill of Materials
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Layout Prints
      4. 4.1.4 Altium Project
      5. 4.1.5 Gerber Files
      6. 4.1.6 Assembly Drawings
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  11. 5About the Author

2.2.3 Power Design

The voltage regulators are chosen to support a current draw up to 2A from the 3.3V supply rail. TAC5312-Q1 is optimized to operate on a single 3.3V supply for AVDD, IOVDD, BSTVDD, and BSTSW pins. AVDD and IOVDD pins draw less than 50mA of current. BSTVDD is a switching current due to the internal boost operating in discontinuous mode resulting in an average current draw of 250mA and peak current draw of 1.3A. The VBATIN pin on TAC5312-Q1 is a reference voltage for input fault diagnostics and does not draw current.

The only external components necessary for the two regulators are input and output capacitors. Input capacitors improve transient performance and can improve noise rejection. Output capacitors are necessary for voltage stability.

The LMR43620-Q1 device has a recommendation that an input capacitor of at least 4.7µF is used to reduce ripple current and isolate switching noise from surrounding circuits. The voltage rating must be higher than the maximum input, so a 50V capacitor is used. The recommended output capacitors are three 22µF capacitors to improve transient response and add stability for a 5V output. The TPS7A52-Q1 device has a recommendation that a 10µF or greater input capacitor is used to minimize input impedance. For this design, the output capacitors following LMR43620-Q1 is tied to the input of TPS7A52-Q1. The output capacitor minimum is 10µF for this design.