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 System Design Theory

Predictive maintenance of smart meters is one of the main topics which is addressed in the TIDA-01546 design, and it is becoming more relevant for many other IoT applications, such as battery-powered sensor nodes.

The TIDA-01546 reference design is designed to accurately monitor the battery health of non-rechargeable lithium batteries and detect any overcurrent conditions in the system. The TM4C1294 MCU is programmed to control the BQ35100 gauge monitor and the ADS7142 sensor monitor. A microSD™ card inserted into the SD card slot can record the battery-monitoring data.

The system health monitoring section of the TIDA-01546 reference design monitors user definable overcurrent conditions during run time and is implemented with the ADS7142 current monitor and LPV521 operational amplifier. The host MCU (TM4C1294) communicates through the I2C interface with the ADS7142 device, which has a digital window comparator with a dedicated ALERT output pin for interrupting the host when the software-programmable high or low threshold is crossed.