BQ24100 Datasheet, PDF(12/26 Page) Texas Instruments – SYNCHRONOUS SWITCHMODE, LI-ION AND LI-POL CHARGE MANAGEMENT IC WITH INTEGRATED POWERFETS

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BQ24100 Datasheet, PDF (12/26 Pages) Texas Instruments – SYNCHRONOUS SWITCHMODE, LI-ION AND LI-POL CHARGE MANAGEMENT IC WITH INTEGRATED POWERFETS

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bq24100, bq24103

bq24105, bq24108

bq24113, bq24115

SLUS606C â JUNE 2004 â REVISED SEPTEMBER 2005

FUNCTIONAL DESCRIPTION FOR STAND-ALONE VERSION (bq2410x)

www.ti.com

The bqSWITCHERâ¢ supports a precision Li-ion or Li-polymer charging system for single-, two- or three-cell

applications. See Figure 4 and Figure 5 for operational flow charts and Figure 6 for a typical charge profile.

Regulation Voltage

Regulation Current

Precharge

Phase

Current Regulation Phase

Voltage Regulation and

Charge Termination Phase

VLOW

Charge Voltage

VSHORT

Charge Current

Precharge

and Termination

ISHORT

UDG-04037

Precharge

Timer

Programmable

Safety Timer

Figure 6. Typical Charging Profile

Temperature Qualification

The bqSWITCHER continuously monitors battery temperature by measuring the voltage between the TS pin and

VSS pin. A negative temperature coefficient thermistor (NTC) and an external voltage divider typically develop

this voltage. The bqSWITCHER compares this voltage against its internal thresholds to determine if charging is

allowed. To initiate a charge cycle, the battery temperature must be within the V(LTF)-to-V(HTF) thresholds. If

battery temperature is outside of this range, the bqSWITCHER suspends charge and waits until the battery

temperature is within the V(LTF)-to-V(HTF) range. During the charge cycle (both precharge and fast charge), the

battery temperature must be within the V(LTF)-to-V(TCO) thresholds. If battery temperature is outside of this range,

the bqSWITCHER suspends charge and waits until the battery temperature is within the V(LTF)-to-V(HTF) range.

The bqSWITCHER suspends charge by turning off the PWM and holding the timer value (i.e., timers are not

reset during a suspend condition). Note that the bias for the external resistor divider is provided from the VTSB

output. Applying a constant voltage between the V(LTF)-to-V(HTF) thresholds to the TS pin disables the

temperature-sensing feature.

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