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

3.1.2 TPS62840 Subsystem

The transient load response with the TPS62840 buck device on the TIDA-10053 reference design was tested under these conditions:

  • VIN = 5.0 V; VOUT = 3.3 V
  • Io_min = 0 A; Io_max = 250 mA
  • Period = 2s; duty cycle = 50%
  • SR = 0.8 A/ns

The zero A are simulating the typically < 5 µA in deep-sleep mode, while the 250 mA are derived from 220 mA (typical current at +23-dBm TX power level for the u-blox and Quectel NB IoT Modules) +25-mA margin in case of maximum current + 5 mA for the rest of the application (Host MCU + Metrology + all other subsystems of a smart meter).

The transient load test result for the 2-second pulse (3.3 Vout is set) is shown in Figure 3-1, with the output voltage being regulated between Vo_min = 3.2987 V and Vo_max = 3.3373 V.

GUID-172DB491-0244-437D-A0AA-4C59380E70D1-low.png Figure 3-1 TPS62840 Transient Load Response for 0- to 250-mA Step

The efficiency is confirmed by having the device operating at PWM mode with switching frequency Fsw = approximately 1.8 MHz.

PIN Poutput EFFICIENCY (%)
4.950 V × 0.522 A = 2.58 W 3.301 V × 0.7094 A = 2.34 W 90.63