TIDUET0A November   2019  – July 2020

 

  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
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS61088-Q1
      2. 2.3.2 LMR33630-Q1
      3. 2.3.3 TPS7A2501
      4. 2.3.4 ATL431AIBDZR
    4. 2.4 System Design Theory
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Related Documentation
    1. 5.1 Trademarks
    2. 5.2 Third-Party Products Disclaimer
  11. 6About the Author
  12. 7Revision History

3.2.2 Test Results

Figure 3-1 and Figure 3-2 show the charge voltage and the charge current across a 2000mAh LiFePO4 capacitor. The initial charge current is well limited. The charge current is 100mA.

GUID-B7A9F77F-69FD-450A-9373-0B78AA2C52F9-low.pngFigure 3-1 Charge Voltage and Charge Current-1
GUID-03A25D2F-0110-474C-9B4D-22F4F4313D0C-low.pngFigure 3-2 Charge Voltage and Charge Current-2

Figure 3-3 shows the conversion efficiency of the TPS61088-Q1 boost converter under 1.5A load current. The conversion efficiency is quite high even the backup battery voltage drops to 2 V.

GUID-35FCD953-EF53-4517-B287-ABD529F6B748-low.gifFigure 3-3 TPS61088-Q1 Efficiency curve