BQ24013 Datasheet, PDF(12/21 Page) Texas Instruments – SINGLE-CHIP, LI-ION CHARGE MANAGEMENT IC FOR HANDHELD APPLICATIONS (bq TINY)

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BQ24013 Datasheet, PDF (12/21 Pages) Texas Instruments – SINGLE-CHIP, LI-ION CHARGE MANAGEMENT IC FOR HANDHELD APPLICATIONS (bq TINY)

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bq24010, bq24012, bq24013, bq24014

SLUS530F â SEPTEMBER 2002 â REVISED AUGUST 2005

FUNCTIONAL DESCRIPTION

www.ti.com

BATTERY PRE-CONDITIONING

During a charge cycle if the battery voltage is below the V(LOWV) threshold, the bqTINY applies a precharge current,

IO(PRECHG), to the battery. This feature revives deeply discharged cells. The resistor connected between the ISET

and VSS, RSET, determines the precharge rate. The V(PRECHG) and K(SET) parameters are specified in the

specifications table.

(PRECHG)

V(PRECHG)

RSET

K(SET)

(11)

The bqTINY activates a safety timer, t(PRECHG), during the conditioning phase. If V(LOWV) threshold is not reached

within the timer period, the bqTINY turns off the charger and enunciates FAULT on the STAT1 and STAT2 pins. Refer

to Timer Fault Recovery section for additional details.

BATTERY CHARGE CURRENT

The bqTINY offers on-chip current regulation with programmable set point. The resistor connected between the ISET

and VSS, RSET, determines the charge rate. The V(SET) and K(SET) parameters are specified in the specifications

table.

(OUT)

V(SET) K(SET)

RSET

(12)

BATTERY VOLTAGE REGULATION

Voltage regulation feedback is accomplished through the BAT pin. This input is tied directly and close to the positive

side of the battery pack. The bqTINY monitors the battery-pack voltage between the BAT and VSS pins. When the

battery voltage rises to VO(REG) threshold, the voltage regulation phase begins and the charging current begins to

taper down.

As a safety backup, the bqTINY also monitors the charge time in the charge mode. If termination does not occur within

this time period, t(CHG), the bqTINY turns off the charger and enunciates FAULT on the STAT1 and STAT1 pins. Refer

to the Timer Fault Recovery section for additional details.

CHARGE TAPER DETECTION, TERMINATION AND RECHARGE

The bqTINY monitors the charging current during the voltage regulation phase. Once the taper threshold, I(TAPER),

is detected the bqTINY initiates the taper timer, t(TAPER). Charge is terminated after the timer expires. The resistor

connected between the ISET and VSS, RSET, determines the taper detection level. The V(TAPER) and K(SET)

parameters are specified in the specifications table.

I (TAPER)

V(TAPER)

RSET

K(SET)

(13)

The bqTINY resets the taper timer in the event that the charge current returns above the taper threshold, I(TAPER).

In addition to the taper current detection, the bqTINY terminates charge in the event that the charge current falls below

the I(TERM) threshold. This feature allows for quick recognition of a battery removal condition or insertion of a fully

charged battery. Note that taper timer is not used for I(TERM) detection. The resistor connected between the ISET

and VSS, RSET, determines the taper detection level. The V(TERM) and K(SET) parameters are specified in the

specifications table.

I (TERM)

V(TERM) K(SET)

RSET

(14)

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