R

SR

Adapter

4.5-24V

HOST

bq24725A

Hybrid Power

Boost Charge

Controller

SYS

Battery

Pack

N-FET Driver

N-FET Driver

1S-4S

SMBus

SMBus Controls V & I

with high accuracy

Adapter Detection

Enhanced Safety:

OCP, OVP, FET Short

Integration:

Loop Compensation; Soft-Start

Comparator

R

AC

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

bq24725A

SLUSAL0A – SEPTEMBER 2011 – REVISED AUGUST 2014

bq24725A 1-4 Cell Li+ Battery SMBus Charge Controller with N-Channel Power MOSFET

Selector and Advanced Circuit Protection

1 Features

3 Description

The bq24725A is a high-efficiency, synchronous

1

•

SMBus Host-Controlled NMOS-NMOS

battery charger, offering low component count for

Synchronous Buck Converter with Programmable

space-constraint, multi-chemistry battery charging

615kHz, 750kHz, and 885kHz Switching

applications.

Frequencies

The

bq24725A

utilizes

two

charge

pumps

to

•

Automatic N-channel MOSFET Selection of

separately

drive

n-channel

MOSFETs

(ACFET,

System Power Source from Adapter or Battery

RBFET and BATFET) for automatic system power

Driven by Internal Charge Pumps

source selection.

•

Enhanced Safety Features for Over Voltage

SMBus controlled input current, charge current, and

Protection, Over Current Protection, Battery,

charge voltage DACs allow for very high regulation

Inductor and MOSFET Short Circuit Protection

accuracies that can be easily programmed by the

•

Programmable Input Current, Charge Voltage,

system power management micro-controller.

Charge Current Limits

The bq24725A uses internal input current register or

–

±0.5% Charge Voltage Accuracy up to 19.2V

external ILIM pin to throttle down PWM modulation to

–

±3% Charge Current Accuracy up to 8.128A

reduce the charge current.

–

±3% Input Current Accuracy up to 8.064A

The bq24725A charges one, two, three or four series

–

±2% 20x Adapter Current or Charge Current

Li+ cells.

Amplifier Output Accuracy

Device Information(1)

•

Programmable Battery Depletion Threshold, and

PART NUMBER

PACKAGE

BODY SIZE (NOM)

Battery LEARN Function

bq24725A

VQFN (20)

3.50mm x 3.50mm

•

Programmable Adapter Detection and Indicator

(1) For all available packages, see the orderable addendum at

•

Integrated Soft Start

the end of the datasheet.

•

Integrated Loop Compensation

•

Real Time System Control on ILIM pin to Limit

Charge Current

•

AC Adapter Operating Range 4.5V-24V

•

5µA Off-State Battery Discharge Current

•

0.65mA (0.8mA max) Adapter Standby Quiescent

Current

•

2 Applications

•

Portable Notebook Computers, UMPC, Ultra-Thin

Notebook, and Netbook

•

Handheld Terminal

•

Industrial and Medical Equipment

•

Portable Equipment

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.