BQ24721 Datasheet, PDF (1/48 Pages) Texas Instruments – ADVANCED MULTI-CHEMISTRY AND MULTI-CELL SYNCHRONOUS SWITCH-MODE CHARGER AND SYSTEM POWER SELECTOR

bq24721
www.ti.com
SLUS683 – NOVEMBER 2005
ADVANCED MULTI-CHEMISTRY AND MULTI-CELL SYNCHRONOUS SWITCH-MODE
CHARGER AND SYSTEM POWER SELECTOR
FEATURES
• High Efficiency NMOS-NMOS Synchronous
Buck Converter With User-Selectable 300 kHz
or 500 kHz frequency
• SBS-Like ⁽¹⁾ SMBus Interface for Control and
Status Communications With Host
• Programmable Battery Voltage, Charge
Current, and AC Adapter Current via SBS-Like
SMBus Interface
• 0.4% Charge Voltage Regulation Accuracy
• 3% Charge Current Regulation Accuracy
• 3% Adapter Current Regulation Accuracy
Dynamic Power Management (DPM)
• 2% Accuracy Integrated Charge and AC
Adapter 20x Current Amplifier Output
• Battery Pack Voltage Range 0 V – 19.2 V
• AC Adapter Operating Range 8 V – 28 V
• 99.5% Max Duty Cycle
• Internal Soft Start
• Integrated 5% 5-V LDO When AC Adapter
Applied
• 6-V Drive Supply Voltage for Increased
Efficiency
• Reverse Battery to Adapter Discharge
Protection
• Battery/Adapter to System Power Selector
Function
• Charge and Adapter Overcurrent Protection
• Battery Thermistor Sense, TS, Comparators
• Available in 32-Pin 5x5mm QFN Package
(1) SBS-Like interface is not 100% SBS compliant. SBS-Like
interface is SMBus1.1 complaint but does not support Packet
Error Correction (PEC). The control and status registers were
changed to simplify and enhance notebook charger control.
An eight bit address (0x12) is used. See Table 1 for a
comparison between SBS-like vs SBS Specification.
APPLICATIONS
• Portable Notebook Computers
• Portable DVD Players
• Webpads, PC Tablets
DESCRIPTION
The bq24721 is a simple to use, high efficiency
synchronous battery pack charger with high level of
integration for portable applications. This device
implements a high performance analog front-end that
easily interfaces to the system power management
micro-controller through a simplified SBS-like SMBus
interface.
The dynamic power management (DPM) function
modifies the charge current depending on system
load conditions, avoiding ac adapter overload.
High accuracy current sense amplifiers enable
accurate measurement of either the charge current or
the ac adapter current, allowing termination of
nonsmart packs and monitoring of overall system
power.
The adapter isolation diode can be bypassed with an
external MOSFET using a control signal provided by
the bq24721, thus reducing overall power dissipation.
Integrated features such as charger soft start, charge
overcurrent protection, and IC temperature monitoring
provide a second level of protection, in addition to
pack and system protection functions.
5x5 QFN PACKAGE (TOP VIEW)
CHGEN 1
ACDRV ²
ACN 3
ACP ⁴
ACDET 5
BYPASS ⁶
EAO ⁷
EAI 8
bq24721
24 BATDRV
23 SYS
22 SYNP
21 SYNN
20 SRP
19 _SRN
18 BAT
17 _IOUT
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005, Texas Instruments Incorporated