SLUAAT5 December   2023 BQ25756

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2LiFePO4 Charging Profile
  6. 3BQ25756 Settings For LiFePO4
    1. 3.1 Set Charging Voltages
      1. 3.1.1 Regulation Voltage
      2. 3.1.2 Recharge Voltage
      3. 3.1.3 Battery Low Voltage
    2. 3.2 Set Charging Current
      1. 3.2.1 Charging Current
        1. 3.2.1.1 ICHG Pin Pull Down Resistor
        2. 3.2.1.2 ICHG_REG Register Bits
      2. 3.2.2 Pre-Charge Current
      3. 3.2.3 Termination Current
    3. 3.3 TS Pin Setting
      1. 3.3.1 JEITA Enabled
      2. 3.3.2 JEITA Disabled
      3. 3.3.3 NTC Monitoring Disabled
  7. 4Supercapacitor Charging Profile
  8. 5SBQ25756 Settings For Supercapacitor
    1. 5.1 Charge Current Setting
    2. 5.2 Charge Voltage Setting
    3. 5.3 TS Pin Setting
  9. 6Test Results From EVM
    1. 6.1 Charging LiFePO4 Battery
    2. 6.2 Charging Supercapacitor
  10. 7Summary
  11. 8References

3.3.1 JEITA Enabled

Assuming a 103AT NTC thermistor on the battery pack, a resistor divider from REGN connected to TS pin and to the battery pack thermistor sets the T1 and T5 temperature window beyond which charging is disabled. As shown in the figure blow, in T1<TS<T2 charge current is reduced and in T3<TS<T5 battery regulation voltage is reduced. The blue trace is the default behavior and the red traces shows programmable range which can be set in REG0x1B.


GUID-20231205-SS0I-40BW-HSC5-LDZC9TPCXLDW-low.svg

Figure 3-2 TS charging values

GUID-20231205-SS0I-HKJ3-DD6R-M53TP96RK6HC-low.svg

Figure 3-3 Resistive divider to TS pin