BQ24705 Datasheet, PDF (1/30 Pages) Texas Instruments – Host-Controlled Multi-Chemistry Battery Charger With Low Input Power Detect

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bq24705
SLUS779 – DECEMBER 2007
Host-Controlled Multi-Chemistry Battery Charger With Low Input Power Detect
FEATURES
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• NMOS-NMOS Synchronous Buck Converter
with 600 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
– Input Overvoltage Protection (OVP)
– Dynamic Power Management (DPM) with
Status Indicator
– Reverse-Conduction Protection Input FET
• 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
– 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
– Current Drawn from Input Source
• Supports Any Battery Chemistry: Li+, NiCd,
NiMH, Lead Acid, etc.
• Charge Enable
• 10-µA Off-State Battery Current
• 24-pin, 4x4-mm QFN Package
APPLICATIONS
• Notebook and Ultra-Mobile Computers
• Portable Data-Capture Terminals
• Portable Printers
• Medical Diagnostics Equipment
• Battery Bay Chargers
• Battery Back-Up Systems
DESCRIPTION
The bq24705 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. 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 bq24705 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.
PVCC 1
CE 2
ACN 3
ACP ⁴
ACDET ⁵
ACSET 6
24 23 22 21 20 19
18 DPMDET
17 CELLS
16 SRP
15 SRN
14 BAT
13 SRSET
7
89
10 11 12
Figure 1. bq24705, 24 LD QFN, Top View
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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