Texas Instruments bq24725A Manual

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

1 Features

• SMBus Host-Controlled NMOS-NMOS
1
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 LEARN 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 4.5V-24V
• 5µA Off-State Battery Discharge Current
• 0.65mA (0.8mA max) Adapter Standby Quiescent
Current
2
• 20-pin 3.5 x 3.5 mm VQFN Package

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.
Sample &
Product
Buy
Folder
Selector and Advanced Circuit Protection
Tools &
Technical
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SLUSAL0A – SEPTEMBER 2011 – REVISED AUGUST 2014

3 Description

The bq24725A is a high-efficiency, synchronous
battery charger, offering low component count for
space-constraint, multi-chemistry battery charging
applications.
The bq24725A utilizes two charge pumps to
separately drive
RBFET and BATFET) for automatic system power
source selection.
SMBus controlled input current, charge current, and
charge voltage DACs allow for very high regulation
accuracies that can be easily programmed by the
system power management micro-controller.
The bq24725A uses internal input current register or
external ILIM pin to throttle down PWM modulation to
reduce the charge current.
The bq24725A charges one, two, three or four series
Li+ cells.
Device Information
PART NUMBER
bq24725A
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Adapter
4.5-24V
N-FET Driver
Adapter Detection
SMBus Controls V & I
with high accuracy
SMBus
HOST
Support &
Community
bq24725A
n-channel MOSFETs
(1)
PACKAGE BODY SIZE (NOM)
VQFN (20) 3.50mm x 3.50mm
R
AC
Enhanced Safety:
OCP, OVP, FET Short
N-FET Driver
bq24725A
Hybrid Power
Boost Charge
R
SR
Controller
Integration:
Loop Compensation; Soft-Start
Comparator
(ACFET,
SYS
Battery
Pack
1S-4S