bq24740

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
Sense Resistor) – Adapter Current Limit (DPM) • Status and Monitoring Outputs – AC/DC Adapter Present with Programmable
Voltage Threshold – Low Input-Power Detect with Adjustable
DPMDET CELLS SRP SRN BAT SRSET IADAPT
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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.
Host-Controlled Multi-Chemistry Battery Charger With Low Input Power Detect
FEATURES
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•2 NMOS-NMOS Synchronous Buck Converter with 300 kHz Frequency and >95% Efficiency
• 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 10 A, with 10-mΩ
The bq24740 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.
Threshold and Hysteresis – DPM Loop Active – Current Drawn from Input Source • Battery Discharge Current Sense with No Adapter, or Selectable Low-Iq mode • Supports Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc. • Charge Enable • 10-µA Off-State Current • 28-pin, 5x5-mm QFN package
bq24740
............................................................................................................................................... SLUS736C – DECEMBER 2006 – REVISED MARCH 2009
Copyright © 2006–2009, Texas Instruments Incorporated
bq24740
SLUS736C – DECEMBER 2006 – REVISED MARCH 2009...............................................................................................................................................
Product Folder Link(s) :bq24740
• Integration – Internal Loop Compensation – Internal Soft Start
• Safety – Input Overvoltage Protection (OVP) – Dynamic Power Management (DPM) with Status Indicator
VIN = 20 V, VBAT = 3-cell Li-Ion, ICHARGE = 3 A, IADAPTER_LIMIT = 4 A
Figure 1. Typical System Schematic, Voltage and Current Programmed by DAC
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DESCRIPTION (CONTINUED)
The bq24740 features Dynamic Power Management (DPM) and input power limiting. These features reduce battery charge current when the input power limit is reached to avoid overloading the ac adapter when supplying the load and the battery charger simultaneously. A current-sense amplifier enables precise measurement of input current from the ac adapter to monitor the overall system power. If the adapter current is above the programmed low-power threshold, a signal is sent to host so that the system optimizes its power performance according to what is available from the adapter.
• 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
P RSR 0.010 Ω
C14 0.1 µF
SRP SRN BAT
LPREF ISYNSET
PowerPad
R6 24 kΩ
VREF R7 200 kΩ
R8 24.9 kΩ
C15 0.1 µF
C12 10 µF
PACK+ PACK-
R9 1.8 MΩ
( 1 ) Pull - up rail could be either VREF or other system rail . ( 2 ) SRSET /ACSET could come from either DAC or resistor dividers .
Pห้องสมุดไป่ตู้CC
C8 0.1 µF
Q3(BATFET ) SI4435
Controlled by HOST
HIDRV PH
BTST REGN
LODRV PGND
C9 D1 BAT 54 0.1 µF
C10 1 µF
N N
Q4 FDS 6680A
L1
8.2 µH C11 10 µF
C13 0.1 µF Q5 FDS6680 A
IADSLP AGND VREF VDAC VADJ
EXTPWR ISYNSET
APPLICATIONS
• Notebook and Ultra-Mobile Computers • Portable Data-Capture Terminals • Portable Printers • Medical Diagnostics Equipment • Battery Bay Chargers • Battery Back-up Systems
PVCC BTST HIDRV PH REGN LODRV PGND
CHGEN ACN ACP
LPMD ACDET ACSET LPREF
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bq24740
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28 LD QFN
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TOP VIEW
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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.