TIDUDT4A May   2018  – November 2021 AM3351 , AM3352 , AM3354 , AM3356 , AM3357 , AM3358 , AM3358-EP , AM3359


  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Power Rails Requirements of the System
      2. 2.2.2 Power Sequencing Requirements of the System
      3. 2.2.3 Uncontrolled Power Off
      4. 2.2.4 12-V Input Voltage Rail
    3. 2.3 Highlighted Products
      1. 2.3.1 TLV62568/9
      2. 2.3.2 LM3881
      3. 2.3.3 TLV803
      4. 2.3.4 AM335x
      5. 2.3.5 WL1837MOD
    4. 2.4 System Design Theory
      1. 2.4.1 Power Tree Architecture
      2. 2.4.2 Power Sequencing Solution
        1. Design Steps for DC-DCs
        2. Design Steps for the Sequencer
        3. Design Steps for the Supervisor
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. Connector Configuration of TIDA-01568
        2. Procedure for Board Bring-up and Testing
      2. 3.1.2 Software
        1. Description of Environment Implementation
        2. How to Customize the Processor SDK for This Reference Design
      3. 3.1.3 Software Bring-up Tips
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
        1. Power-Up and Power-Down Sequence Test
        2. Typical Characteristics of DC-DCs
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 PCB Layout Guidelines
      2. 4.3.2 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7About the Author
  13. 8Revision History

System Description

Smart appliances offer new features and high performance that have been integrated into appliances gradually, such as voice recognition, wireless connectivity, advanced Human Machine Interface (HMI), advanced interaction, and so forth. Processors with high performance and wireless connectivity devices are widely used in smart appliance control platforms. TI’s SitaraTM AM335x family and WiLink8TM family are ideal choices for control systems in smart appliance .

The processors or digital devices usually require different power supply voltages, mixed together on the board with the correct power sequence. Power supply voltages turned on with an incorrect power sequence can cause reliability problems such as characteristics degradation, inrush currents, and latch-up conditions. The challenge is how to design the power tree with correct sequencing without trading off factors such as power tree architect, efficiency, cost, size, and more.

This reference design provides a 5-rail multi-channel power sequencing solution. The small form factor of 12 mm × 12 mm is achieved by using the TLV62568/9, offering 1.5-MHz switching frequency in a small package of SOT-563. The correct power sequence is achieved by using the LM3881, offering three open-drain output flags with individual time delays to avoid latch conditions or large inrush currents that can affect the reliability of the system. This power sequencing solution also supports the uncontrolled power off by using a supervisor of the TLV803 to monitor the input voltage rail, while also generating the power reset signal to manage the power up and power down sequence.

The test report evaluates this power sequencing platform, powering the AM335x and WL1837MOD with all necessary components as a system control platform such as: 4GB eMMC, 256M × 16-Bit DDR3L, microSD™ Card, EEPROM, and USB host. The test result provides the details of the power up and power down sequence, and the typical characters of DC-DCs.