bq24751A
www.ti.com
SLUS756–SEPTEMBER 2007
Host-controlled Multi-Chemistry Battery Charger With System Power Selector, AC
Over-Power Protection, Programmable OVP and Low Iq
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FEATURES
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28-pin, 5x5-mm QFN package
Energy Star Low Iq
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NMOS-NMOS Synchronous Buck Converter
with 300 kHz Frequency and >95% Efficiency
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< 10-μA Off-State Battery Discharge Current
30-ns Minimum Driver Dead-time and 99.5%
Maximum Effective Duty Cycle
< 1.5-mA Off-State Input Quiescent Current
High-Accuracy Voltage and Current Regulation
APPLICATIONS
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Notebook and Ultra-Mobile Computers
Portable Data Capture Terminals
Portable Printers
Medical Diagnostics Equipment
Battery Bay Chargers
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±0.5% Charge Voltage Accuracy
±3% Charge Current Accuracy
±3% Adapter Current Accuracy
±2% Input Current Sense Amp Accuracy
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Integration
Battery Back-up Systems
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Automatic System Power Selection From
AC/DC Adapter or Battery
Internal Loop Compensation
Internal Soft Start
DESCRIPTION
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The bq24751A is a high-efficiency, synchronous
battery charger with integrated compensation and
system power selector logic, offering low component
count for space-constrained multi-chemistry battery
charging applications. Ratiometric charge current and
voltage programming allows very high regulation
accuracies, and can be either hardwired with resistors
or programmed by the system power-management
microcontroller using a DAC or GPIOs.
Safety
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Programmable Input Overvoltage
Protection (OVP)
Dynamic Power Management (DPM) with
Status Indicator
Programmable Inrush Adapter Power
(ACOP) and Overcurrent (ACOC) Limits
The bq24751A charges two, three, or four series Li+
cells, supporting up to 10 A of charge current, and is
available in a 28-pin, 5x5-mm thin QFN package.
Reverse-Conduction Protection Input FET
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Supports Two, Three, or Four Li+ Cells
5 – 24 V AC/DC-Adapter Operating Range
Analog Inputs with Ratiometric Programming
via Resistors or DAC/GPIO Host Control
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Charge Voltage (4-4.512 V/cell)
27 26 25 24 23 22
28
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CHGEN
ACN
LEARN
20 CELLS
SRP
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Charge Current (up to 10 A, with 10-mΩ
sense resistor)
bq24751A
28 LD QFN
TOP VIEW
ACP
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4
5
6
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Adapter Current Limit (DPM)
ACDRV
ACDET
ACSET
ACOP
18 SRN
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Status and Monitoring Outputs
BAT
17
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AC/DC Adapter Present with Programmable
Voltage Threshold
16 SRSET
IADAPT
15
7
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Current Drawn from Input Source
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9
10 11 12 13 14
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Battery Learn Cycle Control
Supports Any Battery Chemistry: Li+, NiCd,
NiMH, Lead Acid, etc.
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Charge Enable
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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.
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 © 2007, Texas Instruments Incorporated