BQ2057CTSTRG4 Datasheet, PDF (9/30 Pages) Texas Instruments – ADVANCED LINEAR CHARGE MANAGEMENT IC FOR SINGLE-AND TWO-CELL LITHIUM-ION AND LITHIUM-POLYMER

APPLICATION INFORMATION
bq2057, bq2057C
bq2057T, bq2057W
SLUS025F − MAY 2001 − REVISED JULY 2002
Preconditioning
Phase
Current Regulation
Phase
Voltage Regulation and Charge
Termination Phase
Regulation Voltage
Regulation Current
Minimum Charge
Voltage
Preconditioning
and Taper Detect
Figure 3. Typical Charge Profile
qualification and precharge
When power is applied, the bq2057 starts a charge-cycle if a battery is already present or when a battery is
inserted. Charge qualification is based on battery temperature and voltage. The bq2057 suspends charge if the
battery temperature is outside the V_(TS1) to V_(TS2) range and suspends charge until the battery temperature is
within the allowed range. The bq2057 also checks the battery voltage. If the battery voltage is below the
precharge threshold V_(min), the bq2057 uses precharge to condition the battery. The conditioning charge rate
I_(PRECHG) is set at approximately 10% of the regulation current. The conditioning current also minimizes heat
dissipation in the external pass-element during the initial stage of charge. See Figure 3 for a typical
charge-profile.
www.ti.com
9