bq24721C SELECTOR Datasheet

bq24721C Datasheet PDF, Equivalent


Part Number

bq24721C

Description

CHARGER AND SYSTEM POWER SELECTOR

Manufacture

etcTI

Total Page 30 Pages
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Download bq24721C Datasheet PDF


bq24721C
bq24721
bq24721C
www.ti.com.................................................................................................................................................. SLUS683F – NOVEMBER 2005 – REVISED APRIL 2009
ADVANCED MULTI-CHEMISTRY AND MULTI-CELL SYNCHRONOUS SWITCH-MODE
CHARGER AND SYSTEM POWER SELECTOR
FEATURES
1
2 High Efficiency NMOS-NMOS Synchronous
Buck Converter With User-Selectable 300 kHz
or 500 kHz frequency
bq24721C Offers Softer Turn-On, Stronger
Turn-Off
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 20× Current Amplifier Output
3-Cell and 4-Cell Li-Ion Voltage Regulation
9 V, 12 V–14.4 V, 16 V–19.2 V
Battery Pack Voltage Operating 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 5x5-mm 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 8-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 high efficiency synchronous battery
pack charger with high level of integration for portable
applications. This device implements a high
performance analog front-end that 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 or
entirely replaced 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,
bq24721C
24 BATDRV
23 SYS
22 SYNP
21 SYNN
20 SRP
19 SRN
18 BAT
17 IOUT
1
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 © 2005–2009, Texas Instruments Incorporated

bq24721C
bq24721
bq24721C
SLUS683F – NOVEMBER 2005 – REVISED APRIL 2009.................................................................................................................................................. www.ti.com
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.
PART NO.
bq24721
bq24721C
PACKAGE
32 PIN
5x5mm QFN
32 PIN
5x5mm QFN
ORDERING INFORMATION
THERMISTOR
SENSE
TS
BATTERY SHORTED
(VERY LOW BATTERY
VOLTAGE) OPERATION
Charge Current Changes to
C/8
TS
Charge Current Changes to
C/8
ORDERING NUMBER
(TAPE AND REEL)
bq24721RHBR
bq24721RHBT
bq24721CRHBR
bq24721CRHBT
QUANTITY
3000
250
3000
250
PACKAGE THERMAL DATA
PACKAGE (1)
RHB (2)
θJA
36°C/W
TA 40°C
POWER RATING
2.36 W
DERATING FACTOR
ABOVE TA = 25°C
0.028 W/°C
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
Web site at www.ti.com.
(2) This data is based on using the JEDEC High-K board and the exposed die pad is connected to a copper pad on the board. This is
connected to the ground plane by a 2×3 via matrix.
TERMINAL
NO. NAME
1 CHGEN
2 ACDRV
3 ACN
4 ACP
5 ACDET
6 BYPASS
7 EAO
DEVICE INFORMATION
TERMINAL FUNCTIONS
DESCRIPTION
Charge enable logic level low input. Logic HI on the CHGEN pin disables the charger. Logic LO on the
CHGEN pin enables the charger. When the SMBus control register = bit0, CHGEN is also LO.
AC adapter to system switch driver output. Connect directly to the gate of the ACFET PMOS power
FET. Connect the FET source to the PVCC node and negative side of the input current-sense resistor.
Connect the FET drain to the system load side. Recommend placing a 100-kresistor from the gate to
the source of the Bypass FET. If needed, an optional capacitor from gate to source of the ACFET is
used to help slow down the ON and OFF times. The internal gate drive is asymmetrical allowing a
quick turn-off and slower turn-off in addition to the internal break-before-make logic with respect to the
BATDRV.
Adapter current sense resistor, negative input. An optional 0.1-µF ceramic capacitor is placed from this
pin to AGND for common-mode filtering. An optional 0.1-µF ceramic capacitor is placed from ACN to
ACP to provide differential-mode filtering.
Adapter current sense resistor, positive input. Place this on the adapter side of the input current sense
resistor. Recommend placing a 0.1-µF ceramic capacitor from ACP to AGND to provide common-mode
filtering.
AC adapter detected sense voltage input. Connect a voltage divider resistor from adapter input (before
Bypass FET) to ACDET, and another resistor from ACDET to AGND, in order to program adapter
detect threshold of 1.2 V. ACDET threshold should be greater than maximum battery regulation
voltage, and lower than the minimum adapter voltage.
Gate drive for the adapter input BYPASS switch to prevent reverse discharge from the battery to the
input. Connect this pin directly to the gate of the input bypass PMOS power FET. The source of the
FET is connected to the adapter input voltage node. Recommend placing a 10-kresistor from the
gate to the source of the BYPASS FET. The drain of the FET is connected to the positive node of the
input current-sense resistor. An optional capacitor can be placed from the gate to the source to
slow-down the switching times. Adjusting the turn-on and turn-off times is typically not needed for this
FET.
Error amplifier output for compensation. Connect the feedback compensation components from EAO to
EAI. Typically a capacitor in parallel with a series resistor and capacitor. See the compensation
calculation procedures. This node is internally compared to the PWM saw-tooth oscillator.
2 Submit Documentation Feedback
Copyright © 2005–2009, Texas Instruments Incorporated
Product Folder Link(s): bq24721 bq24721C


Features bq24721 bq24721C www.ti.com............. ....................................... ....................................... ....................................... ................ SLUS683F – NOVEMBER 2005 – REVISED APRIL 2009 ADVANCED MU LTI-CHEMISTRY AND MULTI-CELL SYNCHRONOU S SWITCH-MODE CHARGER AND SYSTEM POWER SELECTOR FEATURES 1 •2 High Efficien cy NMOS-NMOS Synchronous Buck Converter With User-Selectable 300 kHz or 500 kH z frequency • bq24721C Offers Softer Turn-On, Stronger Turn-Off • SBS-Like (1) SMBus Interface for Control and Sta tus Communications With Host • Progra mmable Battery Voltage, Charge Current, and AC Adapter Current via SBS-Like SM Bus Interface • 0.4% Charge Voltage R egulation Accuracy • 3% Charge Curren t Regulation Accuracy • 3% Adapter Cu rrent Regulation Accuracy Dynamic Power Management (DPM) • 2% Accuracy Integ rated Charge and AC Adapter 20× Curren t Amplifier Output • 3-Cell and 4-Cel l Li-Ion Voltage Regulation 9 V, 12 V–14.4 V, 16 V–19.2 V • Battery Pack Voltage Opera.
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