1FEATURES

2• SMBus Host-Controlled NMOS-NMOS

Synchronous Buck Converter with

Programmable 615kHz, 750kHz, and 885kHz

Switching Frequencies

• Automatic N-channel MOSFET Selection of

System Power Source from Adapter or Battery

Driven by Internal Charge Pumps

• Enhanced Safety Features for Over Voltage

Protection, Over Current Protection, Battery,

Inductor and MOSFET Short Circuit Protection

• Programmable Input Current, Charge Voltage,

Charge Current Limits

– ±0.5% Charge Voltage Accuracy up to 19.2V

– ±3% Charge Current Accuracy up to 8.128A

– ±3% Input Current Accuracy up to 8.064A

– ±2% 20x Adapter Current or Charge Current

Amplifier Output Accuracy

• Programmable Battery Depletion Threshold,

and Battery LERAN Function

• Programmable Adapter Detection and

Indicator

• Integrated Soft Start

• Integrated Loop Compensation

• Real Time System Control on ILIM pin to Limit

Charge Current

• AC Adapter Operating Range 9V-24V

• 5μA Off-State Battery Discharge Current

• 20-pin 3.5 x 3.5 mm2 QFN Package

APPLICATIONS

• Portable Notebook Computers, UMPC, Ultra-

Thin Notebook, and Netbook

• Personal Digital Assistant

• Handheld Terminal

• Industrial and Medical Equipment

• Portable Equipment

DESCRIPTION

The bq24725 is a high-efficiency, synchronous

battery charger, offering low component count for

space-constraint, multi-chemistry battery charging

applications.

The bq24725 uses two charge pumps to separately

drive n-channel MOSFETs (ACFET, RBFET and

BATFET) for automatic system power source

selection.

SMBus controlled input current, charge current, and

charge voltage DACs allow for high regulation

accuracies that can be programmed by the system

power management micro-controller.

The bq24725 uses internal input current register or

external ILIM pin to throttle down PWM modulation to

reduce the charge current.

The bq24725 charges two, three or four series Li+

cells, and is available in a 20-pin, 3.5 x 3.5 mm2 QFN

package.