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

4 Supercapacitor Charging Profile

Most super capacitors can be discharged down to 0 V and recharged to the maximum voltage with the manufacturer recommended charge current. For a super capacitor, trickle charge and pre-charge phase is not required. As a result, the supercapacitor can charge in two phases.

Phase 1 – Constant current:

Charging starts with the full fast charge current and the capacitor voltage increases to the regulation voltage setting.

Phase 2 – Constant voltage:

Once the capacitor voltage reaches the regulation voltage, the charge current is tapered down to zero and the capacitor voltage is held at the regulation voltage.


GUID-20231205-SS0I-BMCH-JQ3K-RB5JZR0HTNTK-low.svg

Figure 4-1 Supercapacitor Charging Profile