SLUAA04A june   2020  – may 2023 BQ25150 , BQ25155 , BQ25618 , BQ25619 , TS5A12301E , TS5A3157 , TS5A3159A , TS5A6542

 

  1.   1
  2.   High-Efficiency Charging for TWS Using a 2-Pin Interface
  3.   Trademarks
  4. 1 Introduction
  5. 2 System Overview
    1. 2.1 Charging Case
      1. 2.1.1 BQ25619
      2. 2.1.2 TLV62568P
      3. 2.1.3 TPS22910A
      4. 2.1.4 TS5A12301E
      5. 2.1.5 MCU
    2. 2.2 Earbuds
      1. 2.2.1 BQ25155
      2. 2.2.2 TPS22910A
      3. 2.2.3 TS5A12301E
      4. 2.2.4 BT/SOC
  6. 3 Charging Case Algorithm Implementation
    1. 3.1 Initialization and Main Code
    2. 3.2 UART Interrupt and Output Voltage Adjustment
  7. 4 Earbud Algorithm Implementation
    1. 4.1 Initialization and Main Code
    2. 4.2 Interrupt and Transmission
  8. 5 Test Procedure
  9. 6 Test Results
    1. 6.1 Dynamic Voltage Adjustment
    2. 6.2 BQ25619 with 4.6-V Output
    3. 6.3 Standard Boost with 5V Output
  10. 7 Summary
  11. 8 Schematics
  12. 9 PCB Layout
  13. 10Software
    1. 10.1 Charging Case main.c
    2. 10.2 Earbuds main.c
  14. 11Revision History

2.1.4 TS5A12301E

This device is the analog switch that is used to pass the UART communication between the earbud and case. This device can switch logic signal down to 1.2 V and has powered off protection. The powered off protection feature allows the device to protect the UART pins on the MCU while the device is in charging mode. Analog switch devices that do not have powered off protection fail for this application because when the earbud input voltage is between 3.3 V and 4.6 V it surpasses the I/O voltage rating many switches have of Vcc + 0.5 V. Without this feature, exceeding this rating can cause an overvoltage event on the MCU GPIO pin.