BQ2057CTSTR 参数 Datasheet PDF下载

bq2057, bq2057C

bq2057T, bq2057W

SLUS025F − MAY 2001 − REVISED JULY 2002

APPLICATION INFORMATION

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.

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