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

2.4.2.3 Current Ranges Simulation With TINA-TI

Figure 2-6 shows the TINA-TI simulation results with the current flowing through the 0.1-Ω resistance. When injecting a 493-mA current into the system, the input voltage of operational amplifier is 69.03 mV (slightly above the calculated 69 mV). The resulting output voltage is 3.29 V, which is close to the calculations in Section 2.4.2.2 and the 3.3 V full-scale voltage.

GUID-7AEB2BC5-BB88-46D2-A43B-7D344499DB88-low.pngFigure 2-6 TINA-TI Simulation for the High-Current Range Using 0.1-Ω Resistor Value

Figure 2-7 shows the simulation of the current flowing through the 6.8-kΩ resistor. With 10-µA current into the system, the input voltage of the LPV521 device is 67.99 mV (a bit below the 69 mV maximum value).

GUID-ABA1FB2A-27E3-4EC6-945B-EE228D719D31-low.pngFigure 2-7 TINA-TI Simulation for the Low-Current Range Using 6.8-kΩ Resistor Value

The simulated output voltage is 3.24 V, also slightly below the maximum allowed voltage of 3.3 V, which is in line with the calculated results.

Using the TINA-TI simulation file included with this reference design, designers can calculate the resistor values required for their application.