BQ24704 Datasheet, PDF (1/31 Pages) Texas Instruments – Low Cost, Host-Controlled Li-Ion and Li-Polymer Battery Charger With Low Iq

bq24704
www.ti.com........................................................................................................................................................................................................ SLUS838 – MAY 2009
Low Cost, Host-Controlled Li-Ion and Li-Polymer Battery Charger With Low Iq
FEATURES
1
•2 NMOS-NMOS Synchronous Buck Converter
with 300 kHz Frequency and >95% Efficiency
• 30-ns Minimum Driver Dead-time and 99.5%
Maximum Effective Duty Cycle
• High-Accuracy Voltage and Current Regulation
– ±0.5% Charge Voltage Accuracy
– ±3% Charge Current Accuracy
– ±3% Adapter Current Accuracy
– ±2% Input Current Sense Amp Accuracy
• Integration
– Internal Loop Compensation
– Internal Soft-Start
• Safety
– Dynamic Power Management (DPM) with
Status Indicator
– Charger Overcurrent Protection
– Battery Overvoltage Protection
– Thermal Shutdown
• Supports Two, Three, or Four Li+ Cells
• 8 – 24 V AC/DC-Adapter Operating Range
• Analog Inputs with Ratiometric Programming
via Resistors or DAC/GPIO Host Control
– Charge Voltage (4-4.512 V/cell)
– Charge Current (up to 8 A, with 10-mΩ
Sense Resistor)
– Adapter Current Limit (DPM)
• Status and Monitoring Outputs
– AC/DC Adapter Present with Programmable
Voltage Threshold
– DPM Loop Active (DPMDET)
– Current Drawn from Input Source
• Charge Enable
• 24-pin, 4x4-mm QFN Package
• Energy Star Low Iq
– < 10 µA Off-state Discharge Current
– < 1.5 mA Off-state Input Quiescent Current
APPLICATIONS
• Notebook and Netbook Computers
• Portable Data-Capture Terminals
• Portable Printers
• Medical Diagnostics Equipment
• Battery Bay Chargers
• Battery Back-Up Systems
DESCRIPTION
The bq24704 is a high-efficiency, synchronous
battery charger with integrated compensation offering
low component count for space-limited Li-Ion and
Li-Polymer battery charging applications. Charge
current and voltage programming allows high
regulation accuracies, and can be either hardwired
with resistors, or programmed by the system
power-management microcontroller using a DAC or
GPIOs.
The bq24704 charges two, three, or four series Li+
cells, supporting up to 8 A of charge current, and is
available in a 24-pin, 4x4-mm thin QFN package.
PACKAGE AND PIN-OUT
PVCC 1
CHGEN 2
ACN 3
ACP ⁴
ACDET ⁵
ACSET 6
24 23 22 21 20 19
bq24704
QFN - 24
TOP VIEW
18 DPMDET
17 CELLS
16 SRP
15 SRN
14 BAT
13 SRSET
7
89
10 11 12
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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.
PowerPad is a trademark of Texas Instruments.
2
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 © 2009, Texas Instruments Incorporated