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

5 Test Procedure

These results were obtained by performing a complete charge cycle of a 195-mAh earbud battery with a fast charge current of 200 mAh. The case was powered by a fully charged 400-mAh battery. The efficiency data was calculated by measuring the instantaneous input voltage and current as well as the output voltage and current. These values were measured at the terminals of the case battery and earbud battery respectively. After obtaining the instantaneous voltage and current, they were multiplied to give the instantaneous input and output power of the system. The instantaneous power was then integrated over the entire charge cycle to give the total input and output energy of the system.

This data was collected using an oscilloscope with a sample rate of 500 S/s over the entire charge cycle of approximately 83 minutes. The voltage data was measured directly across the terminals of each battery. The current data was measured with an INA240 device across a 10-mΩ sense resistor in series with the batteries and the input/output terminals of the system.

The thermal data was taken using a FLIR thermal camera. The ambient room temperature was 25°C, and no direct ventilation was provided to the systems.