TIDUEO0C July   2019  – March 2021

 

  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 TPS63900: 1.8V-5.5 VIN Buck-Boost Converter With 75-nA Ultra-low Quiescent Current and 400-mA Output Current
      2. 2.3.2 TPS610995: 0.7 VIN Synchronous Boost Converter With 400-nA Ultra-low Quiescent Current and 1-A Peak Current
      3. 2.3.3 TPS62840: 750-mA Synchronous Step-Down Converter With Ultra-low Quiescent Current Consumption
    4. 2.4 System Design Theory
      1. 2.4.1 Battery Gauge BQ35100
      2. 2.4.2 In-System Current Monitoring
        1. 2.4.2.1 Resistor Values Calculation for the two Current Ranges
        2. 2.4.2.2 LPV521 Gain Calculation
        3. 2.4.2.3 Current Ranges Simulation With TINA-TI
        4. 2.4.2.4 Key ADS7142 Register Settings in TIDA-01546 Firmware
          1. 2.4.2.4.1 ADS7142 Sampling Rate
      3. 2.4.3 NB-IoT Module From u-blox
      4. 2.4.4 NB-IoT Module From Quectel
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware
      1. 3.1.1 Testing TIDA-010053
      2. 3.1.2 TPS62840 Subsystem
      3. 3.1.3 TPS610995 Subsystem
      4. 3.1.4 Software
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
        1. 3.2.2.1 Test Results With the TPS62840 Buck Converter
        2. 3.2.2.2 Test Results With the TPS610995 Boost Converter
        3. 3.2.2.3 Test Results With the TPS63900 Buck-Boost Converter NB
        4. 3.2.2.4 Summary
  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. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7Terminology
  13. 8About the Author
  14. 9Revision History

3.2.2.3 Test Results With the TPS63900 Buck-Boost Converter NB

GUID-20210115-CA0I-DCCS-HM6F-WZ1CJMTWKWHQ-low.gifFigure 3-11 TPS63900 Buck-Boost Battery Discharge Graph (1s1p Configuration)
GUID-20210115-CA0I-PMFW-HMGJ-63WMMGSVGH2D-low.gifFigure 3-12 TPS63900 Buck-Boost Battery Discharge Graph (1s2p Configuration)

Figure 3-11 and Figure 3-12 demonstrate that when using this power solution, the system supports approximately 75,000 transmission cycles for the 1s1p and 141,000 transmission cycles for the 1s2p (taken at from 100% to 10% SOH) for the simulated NB-IoT load profile. The advantages of using the TPS63900 Buck-Boost Converter is not only its low quiescent current consumption (75 nA typical), but also its high efficiency at light load that minimizes the power losses during the non-transmission period. All of this results in extended product lifetime.

Another feature of the TPS63900 that makes it useful for NB-IoT applications is the dynamic voltage scaling. The part can provide two output voltage levels using two external resistor dividers and by controlling the select pin. This can be used to provide a higher voltage during NB-IoT transmission cycles and can be switched to provide the lower voltage during normal operation when no transmissions are occurring. This feature can be used to further extend the number of transmission cycles shown above.