Texas Instruments bq2057 CW Temperature Data Handbook Manual

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bq2057/C/W/T

Advanced Li-Ion Linear Charge

Management IC low or the high side of the battery

Features General Description

without additional components. The constant-current phase continues

Ideal for single- and dual-cell Li-Ion The BENCHMARQ bq2057 series

un he ba ry reaches the

packs with coke or graphite anodes advanced Li-Ion inear charge-

charge-regulation voltage.

management ICs are designed for

0.3V dropout voltage

cost-sensitive and compact portable

The bq2057 then begins the con-

electronics. They combine high-

Auto Comp™ dynamic compensa- stant-voltage phase. The accuracy of

accuracy cur ren and voltage

tion of battery pack’s internal im- the voltage regulation is better than

regulation, battery conditioning,

pedance ±1% over the operating-temperature

temperature monitoring, charge

and supply-voltage ranges. For sin-

termination, charge-status indi-

Optional temperature-monitoring gle and dual cells with either coke or

cation, and Auto Comp charge-rate

before and during charge graphite anodes, the bq2057 is of-

compensation in single 8-pin IC.

fered in four fixed-voltage versions:

Integrated voltage and current

4.1V, 4.2V, 8.2V, and 8.4V. Charge

The bq2057 continuously measures

regulation with programmable

stops when the current tapers to the

battery temperature using an exter-

charge-current and high- or

charge terminat ion threshold,

nal thermistor. For safety reasons,

low-side current sensing

VTERM. The bq2057 automatically re-

the bq2057 inhibits charge until the

starts the charge if the battery volt-

Integrated cell conditioning for ba te ry tempera ture is within

age falls below the VRCH threshold.

user-defined thresholds. The bq2057

reviving deeply discharged cells

then charges the battery in three

and minimizing heat dissipation The designer also may use the

phases: conditioning, constant cur-

during initial stage of charge Auto Comp feature to reduce charg-

rent, and constant voltage. If the bat-

ing time. This proprietary technique

Better than ±1% voltage regula- tery voltage is below the low-voltage

allows safe and dynamic compensa-

tion accuracy threshold VMIN, the bq2057

tion for the internal impedance of

trickle-charges to condition the bat-

the battery pack during charge.

Charge status output for LED or tery. The conditioning charge rate is host processor interface set at approximately 10% of the reg-

Available Options

ulation current. The conditioning

Automatic battery-recharge feature Charge

current also minimizes heat dissipa-

tion in the external pass-element Regulation

Charge termination by minimum

during the initial stage of charge. Part Number Voltage

current

bq2057 4.1V

After conditioning, the bq2057 ap-

Low-power sleep mode

plies constant current to the bat- bq2057C 4.2V Packaging: 8-pin SOIC, 8-pin tery. An external sense-resistor sets

bq2057T 8.2V

TSSOP the magnitude of the current. The

sense-resistor can be on either the bq2057W 8.4V

Pin Connections Pin Names

STAT Charge status output

SNS Current-sense input

VSS Ground input

BAT Battery-voltage input

CC Charge control output

VCC Supply voltage

COMP Charge-rate

TS Temperature sense

compensation input

input

SLUS025B–JANUARY2000–REVISED JUNE