FEATURES

Highly Integrated Solution With FET Pass

Transistor and Reverse-Blocking Schottky

and Thermal Protection

Timer-Enable Function That Allows Host to

Disable Charge Timer and Termination When

Charge Current Is Shared With a Load or

When Battery Is Absent

Integrated Voltage and Current Regulation

With Programmable Charge Current

High-Accuracy Voltage Regulation (±1%)

Ideal for Low-Dropout Linear Charger

Designs for Single-Cell Li-Ion Packs With

Coke or Graphite Anodes

Up to 1.2-A Continuous Charge Current

Safety-Charge Timer During Preconditioning

and Fast Charge

Integrated Cell Conditioning for Reviving

Deeply Discharged Cells and Minimizing Heat

Dissipation During Initial Stage of Charge

Optional Temperature or Input-Power

Monitoring Before and During Charge

Various Charge-Status Output Options for

Driving Single, Double, or Bicolor LEDs or

Host-Processor Interface

Charge Termination by Minimum Current and

Time

Low-Power Sleep Mode

Packaging: 5 mm × 5 mm MLP (bq24007)or

20-Lead TSSOP PowerPAD

APPLICATIONS

PDAs

Internet Appliances

MP3 Players

Digital Cameras

DESCRIPTION

The bq2400x series ICs are advanced Li-Ion linear

charge management devices for highly integrated and

space-limited applications. They combine highaccuracy

current and voltage regulation; FET passtransistor

and reverse-blocking Schottky; battery

conditioning, temperature, or input-power monitoring;

charge termination; charge-status indication; and

charge timer in a small package.

The bq24007 and bq24008 provide the timer-enable

function, allowing the host to disable the charge timer

when charge current is shared with a load or when the

battery is absent. This feature is ideal for applications

such as cellular phones, PDAs, and internet

appliances.

The bq2400x measures battery temperature using an

external thermistor. For safety reasons, the bq2400x

inhibits charge until the battery temperature is within the

user-defined thresholds. Alternatively, the user can

monitor the input voltage to qualify charge. The

bq2400x series then charge the battery in three phases:

preconditioning, constant current, and constant

voltage. If the battery voltage is below the internal

low-voltage threshold, the bq2400x uses low-current

precharge to condition the battery. A preconditioning

timer provides additional safety. Following preconditioning,

the bq2400x applies a constant-charge

current to the battery. An external sense-resistor sets

the magnitude of the current. The constant-current

phase is maintained until the battery reaches the

charge-regulation voltage. The bq2400x then

transitions to the constant voltage phase. The user can

configure the device for cells with either coke or

graphite anodes. The accuracy of the voltage regulation

is better than ±1% over the operating junction

temperature and supply voltage range.

Charge is terminated by maximum time or minimum

taper current detection

The bq2400x automatically restarts the charge if the

battery voltage falls below an internal recharge

threshold.