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bq27441-G1
SLUSBH1C – NOVEMBER 2013 – REVISED DECEMBER 2014
bq27441-G1 System-Side Impedance Track™ Fuel Gauge
1 Features
2 Applications
•
•
•
•
•
1
•
•
Single Series Cell Li-Ion Battery Fuel Gauge
– Resides on System Board
– Supports Embedded or Removable Batteries
– Powered Directly from Battery with Integrated
LDO
– Supports a Low-Value External Sense Resistor
(10 mΩ)
Battery Fuel Gauging Based on Patented
Impedance Track™ Technology
– Reports Remaining Capacity and State-ofCharge (SOC) with Smoothing Filter
– Automatically Adjusts for Battery Aging, Selfdischarge, Temperature, and Rate Changes
– Battery State-of-Health (Aging) Estimation
Microcontroller Peripheral Supports:
– 400-kHz I2C Serial Interface
– Configurable SOC Interrupt or
Battery Low Digital Output Warning
– Internal Temperature Sensor or
Host-Reported Temperature
Smartphones, Feature Phones, and Tablets
Digital Still and Video Cameras
Handheld Terminals
MP3 or Multimedia Players
3 Description
The Texas Instruments bq27441-G1 fuel gauge is a
microcontroller peripheral that provides system-side
fuel gauging for single-cell Li-Ion batteries. The
device requires minimal user configuration and
system microcontroller firmware development.
The bq27441-G1 battery fuel gauge uses the
patented Impedance Track™ algorithm for fuel
gauging, and provides information such as remaining
battery capacity (mAh), state-of-charge (%), and
battery voltage (mV).
Battery fuel gauging with the bq27441-G1 fuel gauge
requires connections only to PACK+ (P+) and PACK–
(P–) for a removable battery pack or embedded
battery circuit. The tiny, 12-pin, 2.50 mm × 4.00 mm,
small outline no-lead (SON) package is ideal for
space-constrained applications.
Device Information (1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
bq27441-G1
VSON (12)
2.50 mm × 4.00 mm
(1)
For all available packages, see the orderable addendum at
the end of the datasheet.
4 Simplified Schematic
I 2C
Bus
SRN
SCL
Coulomb
Counter
SDA
SRP
CPU
Battery Pack
GPOUT
BIN
VSYS
PACKP
BAT
ADC
Li -Ion
Cell
T
VDD
1.8 V
LDO
VSS
0.47 µF
1 µF
PACKN
Protection
IC
NFET
NFET
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
bq27441-G1
SLUSBH1C – NOVEMBER 2013 – REVISED DECEMBER 2014
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Simplified Schematic.............................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
1
2
3
4
5
8.1 Absolute Maximum Ratings ...................................... 5
8.2 ESD Ratings.............................................................. 5
8.3 Recommended Operating Conditions...................... 5
8.4 Thermal Information .................................................. 5
8.5 Supply Current ......................................................... 6
8.6 Digital Input and Output DC Characteristics ............ 6
8.7 LDO Regulator, Wake-up, and Auto-Shutdown DC
Characteristics ........................................................... 7
8.8 LDO Regulator, Wake-up, and Auto-shutdown AC
Characteristics ........................................................... 7
8.9 ADC (Temperature and Cell Measurement)
Characteristics ........................................................... 7
8.10 Integrating ADC (Coulomb Counter) Characteristics
................................................................................... 7
8.11 I2C-Compatible Interface Communication Timing
Characteristics ........................................................... 8
8.12 SHUTDOWN and WAKE-UP Timing ...................... 9
8.13 Typical Characteristics ............................................ 9
9
Detailed Description ............................................ 10
9.1
9.2
9.3
9.4
9.5
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
Programming...........................................................
10
10
10
11
11
10 Application and Implementation........................ 15
10.1 Application Information.......................................... 15
10.2 Typical Applications .............................................. 15
11 Power Supply Recommendation ....................... 18
11.1 Power Supply Decoupling ..................................... 18
12 Layout................................................................... 18
12.1 Layout Guidelines ................................................. 18
12.2 Layout Example .................................................... 19
13 Device and Documentation Support ................. 20
13.1
13.2
13.3
13.4
Documentation Support ........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
20
20
20
20
14 Mechanical, Packaging, and Orderable
Information ........................................................... 20
5 Revision History
Changes from Revision B (August 2014) to Revision C
Page
•
Changed simplified schematic by adding two 1 µF capacitors ............................................................................................. 1
•
Added description for connecting 1-µF capacitor .................................................................................................................. 4
•
Added information for connecting GPOUT ............................................................................................................................ 4
•
Changed Handling Ratings to ESD Ratings........................................................................................................................... 5
•
Changed connection description for BAT pin ...................................................................................................................... 18
•
Changed recommend to required......................................................................................................................................... 18
•
Added arrow to C BAT from text............................................................................................................................................. 19
Changes from Revision A (January 2014) to Revision B
Page
•
Added Handling Ratings table, Feature Description section, Device Functional Modes, Application and
Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation
Support section, and Mechanical, Packaging, and Orderable Information section ............................................................... 1
•
Changed LiMnO4 to LiCoO2.................................................................................................................................................... 4
•
Updated BAT pin description ................................................................................................................................................. 4
•
Updated BIN pin description .................................................................................................................................................. 4
•
Updated GPOUT pin description ........................................................................................................................................... 4
•
Updated SRN and SRP pin descriptions................................................................................................................................ 4
•
Changed the Ilkg parameters .................................................................................................................................................. 6
2
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Changes from Original (November 2013) to Revision A
•
Page
Changed the device status from Product Preview to Production Data .................................................................................. 1
6 Device Comparison Table
PART NUMBER
BATTERY TYPE
bq27441DRZR-G1A
LiCoO2
(4.2 V maximum charge)
0x0128
LiCoO2
(4.3 to 4.35 V maximum charge)
0x0312
bq27441DRZT-G1A
bq27441DRZR-G1B
bq27441DRZT-G1B
(1)
(2)
(3)
CHEM_ID
(1)
DM_CODE
(2)
FIRMWARE
VERSION (3)
0x48
1.09
(0x0109)
0x58
See the CHEM_ID subcommand to confirm the battery chemistry type.
See the DM_CODE subcommand to confirm the Data Memory code.
See the FW_VERSION subcommand to confirm the firmware version.
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7 Pin Configuration and Functions
GPOUT
BIN
Pin Functions
PIN
NAME
BAT
NUMBER
6
BIN
10
GPOUT
12
TYPE (1)
DESCRIPTION
PI, AI
LDO regulator input and battery voltage measurement input. Kelvin sense connect to positive
battery terminal (PACKP). Connect a capacitor (1 µF) between BAT and VSS. Place the capacitor
close to the gauge.
DI
Battery insertion detection input. If OpConfig [BI_PU_EN] = 1 (default), a logic low on the pin is
detected as battery insertion. For a removable pack, the BIN pin can be connected to VSS
through a pulldown resistor on the pack, typically the 10-kΩ thermistor; the system board should
use a 1.8-MΩ pullup resistor to VDD to ensure the BIN pin is high when a battery is removed. If
the battery is embedded in the system, it is recommended to leave [BI_PU_EN] = 1 and use a
10-kΩ pulldown resistor from BIN to VSS. If [BI_PU_EN] = 0, then the host must inform the gauge
of battery insertion and removal with the BAT_INSERT and BAT_REMOVE subcommands. A 10kΩ pulldown resistor should be placed between BIN and VSS, even if this pin is unused.
NOTE: The BIN pin must not be shorted directly to VCC or VSS and any pullup resistor on the BIN
pin must be connected only to VDD and not an external voltage rail.
DO
This open-drain output can be configured to indicate BAT_LOW when the OpConfig
[BATLOWEN] bit is set. By default [BATLOWEN] is cleared and this pin performs an interrupt
function (SOC_INT) by pulsing for specific events, such as a change in state-of-charge. Signal
polarity for these functions is controlled by the [GPIOPOL] configuration bit. This pin should not
be left floating, even if unused; therefore, a 10-kΩ pullup resistor is recommended. If the device
is in shutdown mode, then toggling GPOUT will make the gauge exit shutdown. Therefore, it is
recommended to connect GPOUT to a GPIO of the host MCU.
No internal connection. May be left floating or tied to VSS.
NC
4, 9, 11
—
SCL
2
DIO
SDA
1
DIO
SRN
7
AI
SRP
8
AI
VDD
5
PO
1.8-V regulator output. Decouple with 0.47-μF ceramic capacitor to VSS. This pin is not intended
to provide power for other devices in the system.
VSS
3
PI
Ground pin
(1)
4
Slave I2C serial bus for communication with system (Master). Open-drain pins. Use with external
10-kΩ pullup resistors (typical) for each pin. If the external pullup resistors will be disconnected
from these pins during normal operation, recommend using external 1-MΩ pulldown resistors to
VSS at each pin to avoid floating inputs.
Coulomb counter differential inputs expecting an external 10 mΩ, 1% sense resistor in the highside current path. Kelvin sense connect SRP to the positive battery terminal (PACKP) side of the
external sense resistor. Kelvin sense connect SRN to the other side of the external sense
resistor, the positive connection to the system (VSYS). See the Simplified Schematic. No
calibration is required. The fuel gauge is pre-calibrated for a standard 10 mΩ, 1% sense resistor.
IO = Digital input-output, AI = Analog input, P = Power connection
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8 Specifications
8.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
VBAT
VSR
MIN
MAX
UNIT
BAT pin input voltage range
–0.3
6
V
SRP and SRN pins input voltage range
–0.3
VBAT + 0.3
V
2
V
2
V
V
Differential voltage across SRP and SRN. ABS(SRP – SRN)
VDD
VDD pin supply voltage range (LDO output)
–0.3
VIOD
Open-drain IO pins (SDA, SCL)
–0.3
6
VIOPP
Push-pull IO pins (BIN)
–0.3
VDD + 0.3
V
TA
Operating free-air temperature range
–40
85
°C
–65
150
°C
Storage temperature, Tstg
(1)
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
8.2 ESD Ratings
VALUE
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
(1)
(2)
Electrostatic discharge
(1)
UNIT
±1500
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
V
±250
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
8.3
Recommended Operating Conditions
TA = 30°C and VREGIN = VBAT = 3.6 V (unless otherwise noted)
MIN
CBAT
(1)
CLDO18 (1)
VPU (1)
(1)
External input capacitor for internal LDO
between BAT and VSS
Nominal capacitor values specified.
Recommend a 5% ceramic X5R-type
External output capacitor for internal LDO capacitor located close to the device.
between VDD and VSS
External pullup voltage for open-drain
pins (SDA, SCL, GPOUT)
TYP
MAX
UNIT
0.1
μF
0.47
μF
1.62
3.6
V
Specified by design. Not production tested.
8.4 Thermal Information
THERMAL METRIC
DRZ (12 PINS)
RθJA
Junction-to-ambient thermal resistance
64.1
RθJCtop
Junction-to-case (top) thermal resistance
59.8
RθJB
Junction-to-board thermal resistance
52.7
ψJT
Junction-to-top characterization parameter
0.3
ψJB
Junction-to-board characterization parameter
28.3
RθJCbot
Junction-to-case (bottom) thermal resistance
2.4
UNIT
°C/W
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8.5
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Supply Current
TA = 30°C and VREGIN = VBAT = 3.6V (unless otherwise noted)
PARAMETER
ICC
(1)
TEST CONDITIONS
MAX
UNIT
μA
21
μA
9
μA
0.6
μA
ILOAD > Sleep Current
SLEEP mode current
ILOAD < Sleep Current (2)
IHIB (1)
HIBERNATE mode current
ILOAD < Hibernate Current (2)
SHUTDOWN mode current
Fuel gauge in host commanded
SHUTDOWN mode.
(LDO regulator output disabled)
(1)
(2)
TYP
93
NORMAL mode current
ISLP (1)
ISD (1)
MIN
(2)
Specified by design. Not production tested.
Wake Comparator Disabled.
8.6
Digital Input and Output DC Characteristics
TA = –40°C to 85°C, typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted)(Force Note1) (1)
PARAMETER
VIH(OD)
TEST CONDITIONS
Input voltage, high (2)
External pullup resistor to VPU
(3)
MIN
TYP
MAX
VPU × 0.7
UNIT
V
VIH(PP)
Input voltage, high
VIL
Input voltage, low (2)
VOL
Output voltage, low (2)
0.6
V
IOH
Output source current, high (2)
0.5
mA
Output sink current, low (2)
–3
mA
5
pF
IOL(OD)
CIN
Ilkg
(1)
1.4
(3)
Input capacitance (2) (3)
Input leakage current
(SCL, SDA, BIN)
0.1
Input leakage current (GPOUT)
(1)
(2)
(3)
6
V
0.6
V
μA
1
Specified by design. Not production tested.
Open Drain pins: (SCL, SDA, GPOUT)
Push-Pull pin: (BIN)
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8.7
SLUSBH1C – NOVEMBER 2013 – REVISED DECEMBER 2014
LDO Regulator, Wake-up, and Auto-Shutdown DC Characteristics
TA = –40°C to 85°C, typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted)(Force Note1) (1)
PARAMETER
VBAT
BAT pin regulator input
VDD
Regulator output voltage
UVLOIT+
VBAT undervoltage lock-out
LDO wake-up rising threshold
UVLOIT–
VBAT undervoltage lock-out
LDO auto-shutdown falling threshold
VWU+ (1)
GPOUT (input) LDO Wake-up rising
edge threshold (2)
(1)
(2)
TEST CONDITIONS
MIN
TYP
2.45
LDO Wake-up from SHUTDOWN
mode
MAX
UNIT
4.5
V
1.8
V
2
V
1.95
V
1.2
V
Specified by design. Not production tested.
If the device is commanded to SHUTDOWN via I2C with VBAT > UVLOIT+, a wake-up rising edge trigger is required on GPOUT.
8.8
LDO Regulator, Wake-up, and Auto-shutdown AC Characteristics
TA = –40°C to 85°C, typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted)
PARAMETER
tSHDN
(1)
tSHUP (1)
tVDD
(1)
TEST CONDITIONS
SHUTDOWN entry time
Time delay from SHUTDOWN
command to LDO output disable.
SHUTDOWN GPOUT low time
Minimum low time of GPOUT (input)
in SHUTDOWN before WAKEUP
tWUVDD (1)
Wake-up VDD output delay
tPUCD
Power-up communication delay
Time delay from rising edge of
REGIN to the Active state. Includes
firmware initialization time.
TYP
MAX
UNIT
250
ms
μs
10
Initial VDD output delay
Time delay from rising edge of
GPOUT (input) to nominal VDD
output.
(1)
MIN
13
ms
8
ms
250
ms
Specified by design. Not production tested.
8.9
ADC (Temperature and Cell Measurement) Characteristics
TA = –40°C to 85°C; typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted) (Force Note1) (1)
PARAMETER
TEST CONDITIONS
VIN(BAT)
BAT pin voltage measurement range Voltage divider enabled
tADC_CONV
Conversion time
MIN
2.45
Effective resolution
(1)
TYP
MAX
UNIT
4.5
V
125
ms
15
bits
Specified by design. Not tested in production.
8.10
Integrating ADC (Coulomb Counter) Characteristics
TA = –40°C to 85°C; typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted)(Force Note1) (1)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VSR
Input voltage range from BAT to
SRX pins
tSR_CONV
Conversion time
Single conversion
1
s
Effective Resolution
Single conversion
16
bits
(1)
BAT ± 25
mV
Specified by design. Not tested in production.
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I2C-Compatible Interface Communication Timing Characteristics
8.11
TA = –40°C to 85°C; typical values at TA = 30°C and VREGIN = 3.6 V (unless otherwise noted) (Force Note1) (1)
MIN
TYP
MAX
UNIT
Standard Mode (100 kHz)
4
μs
4.7
μs
4
μs
4.7
μs
250
ns
td(STA)
Start to first falling edge of SCL
tw(L)
SCL pulse duration (low)
tw(H)
SCL pulse duration (high)
tsu(STA)
Setup for repeated start
tsu(DAT)
Data setup time
Host drives SDA
th(DAT)
Data hold time
Host drives SDA
0
ns
tsu(STOP)
Setup time for stop
4
μs
t(BUF)
Bus free time between stop and start Includes Command Waiting Time
tf
SCL or SDA fall time (1)
tr
SCL or SDA rise time
fSCL
Clock frequency (2)
μs
66
300
(1)
ns
300
ns
100
kHz
Fast Mode (400 kHz)
td(STA)
Start to first falling edge of SCL
600
ns
tw(L)
tw(H)
SCL pulse duration (low)
1300
ns
SCL pulse duration (high)
600
ns
tsu(STA)
Setup for repeated start
600
ns
tsu(DAT)
Data setup time
Host drives SDA
100
ns
th(DAT)
Data hold time
Host drives SDA
0
ns
tsu(STOP)
Setup time for stop
600
ns
t(BUF)
Bus free time between stop and start Includes Command Waiting Time
tf
SCL or SDA fall time (1)
300
tr
SCL or SDA rise time (1)
300
ns
fSCL
Clock frequency (2)
400
kHz
(1)
(2)
μs
66
ns
Specified by design. Not production tested.
If the clock frequency (fSCL) is > 100 kHz, use 1-byte write commands for proper operation. All other transactions types are supported at
400 kHz. (See I2C Interface and I2C Command Waiting Time.)
tSU(STA)
tw(H)
tf
tw(L)
tr
t(BUF)
SCL
SDA
td(STA)
tsu(STOP)
tf
tr
th(DAT)
tsu(DAT)
REPEATED
START
STOP
START
Figure 1. I2C-Compatible Interface Timing Diagrams
8
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8.12 SHUTDOWN and WAKE-UP Timing
tPUCD
tSHUP
tVDD
tSHDN
tPUCD
tWUVDD
REGIN
VDD
I2C Bus
GPOUT
SHUTDOWN_
ENABLE
SHUTDOWN
*
State
Off
WAKE-UP
Active
SHUTDOWN
WAKE-UP
Active
* GPOUT is configured as an input for wake-up signaling.
Figure 2. SHUTDOWN and WAKE-UP Timing Diagram
8.13 Typical Characteristics
0.14
10
0.12
5
Temperature Accuracy Error(%)
Voltage Accuracy Error (%)
0.1
0.08
0.06
0
-5
-10
0.04
0.02
-40
-20
0
20
40
Temperature (°C)
60
80
100
-15
-40
-20
Figure 3. Voltage Accuracy
0
20
40
Temperature (°C)
60
80
100
Figure 4. Temperature Accuracy
0
-0.1
Current Accuracy Error (%)
-0.2
-0.3
-0.4
-0.5
-0.6
-40
-20
0
20
40
Temperature (°C)
60
80
100
Figure 5. Current Accuracy
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9 Detailed Description
9.1 Overview
The fuel gauge accurately predicts the battery capacity and other operational characteristics of a single Li-based
rechargeable cell. It can be interrogated by a system processor to provide cell information, such as state-ofcharge (SoC).
NOTE
The following formatting conventions are used in this document:
Commands: italics with parentheses() and no breaking spaces, for example, Control().
Data Flash: italics, bold, and breaking spaces, for example, Design Capacity.
Register bits and flags: italics with brackets [ ], for example, [TDA]
Data flash bits: italics, bold, and brackets [ ], for example, [LED1]
Modes and states: ALL CAPITALS, for example, UNSEALED mode.
9.2 Functional Block Diagram
I 2C
Bus
SRN
SCL
Coulomb
Counter
SDA
SRP
CPU
Battery Pack
GPOUT
BIN
VSYS
PACKP
BAT
ADC
Li -Ion
Cell
T
VDD
1.8 V
LDO
0.47 µF
1 µF
VSS
PACKN
Protection
IC
NFET
NFET
9.3 Feature Description
Information is accessed through a series of commands, called Standard Commands. Further capabilities are
provided by the additional Extended Commands set. Both sets of commands, indicated by the general format
Command), are used to read and write information contained within the control and status registers, as well as its
data locations. Commands are sent from system to gauge using the I2C serial communications engine, and can
be executed during application development, system manufacture, or end-equipment operation.
The key to the high-accuracy gas gauging prediction is Texas Instruments proprietary Impedance Track™
algorithm. This algorithm uses cell measurements, characteristics, and properties to create state-of-charge
predictions that can achieve high accuracy across a wide variety of operating conditions and over the lifetime of
the battery.
The fuel gauge measures the charging and discharging of the battery by monitoring the voltage across a smallvalue sense resistor. When a cell is attached to the fuel gauge, cell impedance is computed based on cell
current, cell open-circuit voltage (OCV), and cell voltage under loading conditions.
The fuel gauge uses an integrated temperature sensor for estimating cell temperature. Alternatively, the host
processor can provide temperature data for the fuel gauge.
More details are found in the bq27441-G1 Technical Reference Manual (SLUUAC9).
10
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9.4 Device Functional Modes
To minimize power consumption, the fuel gauge has several power modes: INITIALIZATION, NORMAL, SLEEP,
and HIBERNATE. The fuel gauge passes automatically between these modes, depending upon the occurrence
of specific events, though a system processor can initiate some of these modes directly. More details are found
in the bq27441-G1 Technical Reference Manual (SLUUAC9).
9.5 Programming
9.5.1 Standard Data Commands
The fuel gauge uses a series of 2-byte standard commands to enable system reading and writing of battery
information. Each standard command has an associated command-code pair, as indicated in Table 1. Because
each command consists of two bytes of data, two consecutive I2C transmissions must be executed both to
initiate the command function, and to read or write the corresponding two bytes of data. Additional details are
found in the bq27441-G1 Technical Reference Manual (SLUUAC9).
Table 1. Standard Commands
NAME
COMMAND
CODE
UNIT
SEALED ACCESS
Control()
CNTL
0x00 and 0x01
NA
RW
Temperature()
TEMP
0x02 and 0x03
0.1°K
RW
VOLT
0x04 and 0x05
mV
R
FLAGS
0x06 and 0x07
NA
R
0x08 and 0x09
mAh
R
Voltage()
Flags()
NominalAvailableCapacity()
FullAvailableCapacity()
0x0A and 0x0B
mAh
R
RemainingCapacity()
RM
0x0C and 0x0D
mAh
R
FullChargeCapacity()
FCC
0x0E and 0x0F
mAh
R
AverageCurrent()
0x10 and 0x11
mA
R
StandbyCurrent()
0x12 and 0x13
mA
R
MaxLoadCurrent()
0x14 and 0x15
mA
R
AveragePower()
0x18 and 0x19
mW
R
0x1C and 0x1D
%
R
0x1E and 0x1F
0.1°K
R
0x20 and 0x21
num / %
R
RemainingCapacityUnfiltered()
0x28 and 0x29
mAh
R
RemainingCapacityFiltered()
0x2A and 0x2B
mAh
R
FullChargeCapacityUnfiltered()
0x2C and 0x2D
mAh
R
FullChargeCapacityFiltered()
0x2E and 0x2F
mAh
R
StateOfCharge()
SOC
InternalTemperature()
StateOfHealth()
SOH
StateOfChargeUnfiltered()
0x30 and 0x31
%
R
TrueRemainingCapacity()
0x6A and 0x6B
mAh
R
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9.5.2
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Control(): 0x00 and 0x01
Issuing a Control() command requires a subsequent 2-byte subcommand. These additional bytes specify the
particular control function desired. The Control() command allows the system to control specific features of the
fuel gauge during normal operation and additional features when the device is in different access modes, as
described in Table 2. Additional details are found in the bq27441-G1 Technical Reference Manual (SLUUAC9).
Table 2. Control() Subcommands
CNTL DATA
SEALED ACCESS
CONTROL_STATUS
CNTL FUNCTION
0x0000
Yes
Reports the status of device.
DESCRIPTION
FW_VERSION
0x0002
Yes
Reports the firmware version of the device.
DM_CODE
0x0004
Yes
Reports the Data Memory Code number stored in NVM.
PREV_MACWRITE
0x0007
Yes
Returns previous MAC command code.
CHEM_ID
0x0008
Yes
Reports the chemical identifier of the battery profile used by the fuel
gauge.
BAT_INSERT
0x000C
Yes
Forces the Flags() [BAT_DET] bit set when the OpConfig [BIE] bit is 0.
BAT_REMOVE
0x000D
Yes
Forces the Flags() [BAT_DET] bit clear when the OpConfig [BIE] bit is
0.
SET_HIBERNATE
0x0011
Yes
Forces CONTROL_STATUS [HIBERNATE] to 1.
CLEAR_HIBERNATE
0x0012
Yes
Forces CONTROL_STATUS [HIBERNATE] to 0.
SET_CFGUPDATE
0x0013
No
Force CONTROL_STATUS [CFGUPMODE] to 1 and gauge enters
CONFIG UPDATE mode.
SHUTDOWN_ENABLE
0x001B
No
Enables device SHUTDOWN mode.
SHUTDOWN
0x001C
No
Commands the device to enter SHUTDOWN mode.
SEALED
0x0020
No
Places the device in SEALED access mode.
TOGGLE_GPOUT
0x0023
Yes
Commands the device to toggle the GPOUT pin for 1 ms.
RESET
0x0041
No
Performs a full device reset.
SOFT_RESET
0x0042
No
Gauge exits CONFIG UPDATE mode.
EXIT_CFGUPDATE
0x0043
No
Exits CONFIG UPDATE mode without an OCV measurement and
without resimulating to update StateOfCharge().
EXIT_RESIM
0x0044
No
Exits CONFIG UPDATE mode without an OCV measurement and
resimulates with updated configuration data to update StateOfCharge().
9.5.3 Extended Data Commands
Extended data commands offer additional functionality beyond the standard set of commands. They are used in
the same manner; however, unlike standard commands, extended commands are not limited to 2-byte words.
The number of command bytes for a given extended command ranges in size from single to multiple bytes, as
specified in Table 3.
Table 3. Extended Commands
NAME
COMMAND CODE
UNIT
SEALED ACCESS (1)
(2)
UNSEALED ACCESS (1)
OpConfig()
0x3A and 0x3B
NA
R
DesignCapacity()
0x3C and 0x3D
mAh
R
R
R
DataClass()
(2)
0x3E
NA
NA
RW
DataBlock()
(2)
0x3F
NA
RW
RW
BlockData()
0x40 through 0x5F
NA
R
RW
BlockDataCheckSum()
0x60
NA
RW
RW
BlockDataControl()
0x61
NA
NA
RW
0x62 through 0x7F
NA
R
R
Reserved
(1)
(2)
12
(2)
SEALED and UNSEALED states are entered via commands to Control() 0x00 and 0x01.
In SEALED mode, data cannot be accessed through commands 0x3E and 0x3F.
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9.5.4 Communications
9.5.4.1 I2C Interface
The fuel gauge supports the standard I2C read, incremental read, quick read, one-byte write, and incremental
write functions. The 7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as
1010101. The first 8 bits of the I2C protocol are, therefore, 0xAA or 0xAB for write or read, respectively.
Host generated
S
ADDR[6:0]
0 A
Gauge generated
CMD [7:0]
A
DATA [7:0]
A P
S
ADDR[6:0]
(a) 1-byte write
S
ADDR[6:0]
0 A
1 A
DATA [7:0]
N P
(b) quick read
CMD [7:0]
A Sr
ADDR[6:0]
1 A
DATA [7:0]
N P
(c) 1- byte read
S
ADDR[6:0]
0 A
CMD [7:0]
A Sr
ADDR[6:0]
1 A
DATA [7:0]
A ...
DATA [7:0]
N P
(d) incremental read
S
ADDR[6:0]
0 A
CMD[7:0]
A
DATA [7:0]
A
DATA [7:0]
A
...
A P
(e) incremental write
(S = Start , Sr = Repeated Start , A = Acknowledge , N = No Acknowledge , and P = Stop).
The quick read returns data at the address indicated by the address pointer. The address pointer, a register
internal to the I2C communication engine, increments whenever data is acknowledged by the fuel gauge or the
I2C master. “Quick writes” function in the same manner and are a convenient means of sending multiple bytes to
consecutive command locations (such as two-byte commands that require two bytes of data).
The following command sequences are not supported:
Attempt to write a read-only address (NACK after data sent by master):
Attempt to read an address above 0x6B (NACK command):
9.5.4.2 I2C Time Out
The I2C engine releases both SDA and SCL if the I2C bus is held low for 2 seconds. If the fuel gauge is holding
the lines, releasing them frees them for the master to drive the lines. If an external condition is holding either of
the lines low, the I2C engine enters the low-power SLEEP mode.
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9.5.4.3 I2C Command Waiting Time
To ensure proper operation at 400 kHz, a t(BUF) ≥ 66 μs bus-free waiting time must be inserted between all
packets addressed to the fuel gauge. In addition, if the SCL clock frequency (fSCL) is > 100 kHz, use individual 1byte write commands for proper data flow control. The following diagram shows the standard waiting time
required between issuing the control subcommand the reading the status result. For read-write standard
command, a minimum of 2 seconds is required to get the result updated. For read-only standard commands,
there is no waiting time required, but the host must not issue any standard command more than two times per
second. Otherwise, the gauge could result in a reset issue due to the expiration of the watchdog timer.
S
ADDR [6:0]
0 A
CMD [7:0]
A
DATA [7:0]
A P
66ms
S
ADDR [6:0]
0 A
CMD [7:0]
A
DATA [7:0]
A P
66ms
S
ADDR [6:0]
0 A
CMD [7:0]
A Sr
ADDR [6:0]
1 A
DATA [7:0]
A
DATA [7:0]
N P
66ms
N P
66ms
Waiting time inserted between two 1-byte write packets for a subcommand and reading results
(required for 100 kHz < fSCL £ 400 kHz)
S
ADDR [6:0]
0 A
CMD [7:0]
A
DATA [7:0]
S
ADDR [6:0]
0 A
CMD [7:0]
A Sr
ADDR [6:0]
A
1 A
DATA [7:0]
A P
DATA [7:0]
A
66ms
DATA [7:0]
Waiting time inserted between incremental 2-byte write packet for a subcommand and reading results
(acceptable for fSCL £ 100 kHz)
S
ADDR [6:0]
DATA [7:0]
0 A
A
CMD [7:0]
DATA [7:0]
A Sr
N P
ADDR [6:0]
1 A
DATA [7:0]
A
DATA [7:0]
A
66ms
Waiting time inserted after incremental read
9.5.4.4 I2C Clock Stretching
A clock stretch can occur during all modes of fuel gauge operation. In SLEEP and HIBERNATE modes, a short ≤
100-µs clock stretch occurs on all I2C traffic as the device must wake-up to process the packet. In the other
modes (INITIALIZATION, NORMAL), a ≤ 4-ms clock stretching period may occur within packets addressed for
the fuel gauge as the I2C interface performs normal data flow control.
14
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10 Application and Implementation
NOTE
Information in the following application section is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
The bq27441-G1 fuel gauge is a microcontroller peripheral that provides system-side fuel gauging for single-cell
Li-Ion batteries. The device requires minimal configuration and uses One Time Programmable (OTP) NonVolatile Memory (NVM). Battery fuel gauging with the fuel gauge requires connections only to PACK+ and
PACK– for a removable battery pack or embedded battery circuit. To allow for optimal performance in the end
application, special considerations must be taken to ensure minimization of measurement error through proper
printed circuit board (PCB) board layout. Such requirements are detailed in Design Requirements.
10.2 Typical Applications
VPU
R2
VPU
R3
5.1 k
1
SDA
SDA
2
SCL
3
4
PGND
NC
VSS
BIN
NC
SRP
VDD
6
C1
SCL
NC
5
5.1 k
GPOUT
BAT
PWPD
5.1 k
R4
U1
SRN
12
R5
1.8 M
GPOUT
11
10
BIN
9
8
7
13
0.47 µF
PGND
PGND
R1
PACKP
BIN
PACKN
3
2
1
3
2
System Load/Charger
VSYS
C2
1.0uF
BIN
1
0.010
Note: 1% Tol.
J5
PGND
Figure 6. Typical Application
10.2.1 Design Requirements
As shipped from the Texas Instruments factory, many bq27441-G1 parameters in OTP NVM are left in the
unprogrammed state (zero) while some parameters directly associated with the CHEMID are preprogrammed.
This partially programmed configuration facilitates customization for each end application. Upon device reset, the
contents of OTP are copied to associated volatile RAM-based Data Memory blocks. For proper operation, all
parameters in RAM-based Data Memory require initialization — either by updating Data Memory parameters in a
lab/evaluation situation or by programming the OTP for customer production. Chapter 6 in the bq27441-G1
Technical Reference Manual (SLUUAC9) shows the default value and a typically expected value appropriate for
most of applications.
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Typical Applications (continued)
10.2.2 Detailed Design Procedure
10.2.2.1 BAT Voltage Sense Input
A ceramic capacitor at the input to the BAT pin is used to bypass AC voltage ripple to ground, greatly reducing
its influence on battery voltage measurements. It proves most effective in applications with load profiles that
exhibit high-frequency current pulses (that is, cell phones) but is recommended for use in all applications to
reduce noise on this sensitive high-impedance measurement node.
10.2.2.2 Integrated LDO Capacitor
The fuel gauge has an integrated LDO with an output on the VDD pin of approximately 1.8 V. A capacitor of value
at least 0.47 μF should be connected between the VDD pin and VSS. The capacitor should be placed close to the
gauge IC and have short traces to both the VDD pin and VSS.
10.2.2.3 Sense Resistor Selection
Any variation encountered in the resistance present between the SRP and SRN pins of the fuel gauge will affect
the resulting differential voltage, and derived current, it senses. As such, it is recommended to select a sense
resistor with minimal tolerance and temperature coefficient of resistance (TCR) characteristics. The standard
recommendation based on best compromise between performance and price is a 1% tolerance, 50 ppm drift
sense resistor with a 1-W power rating.
16
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Typical Applications (continued)
10.2.3 Application Curves
0.14
10
0.12
5
Temperature Accuracy Error(%)
Voltage Accuracy Error (%)
0.1
0.08
0.06
0
-5
-10
0.04
0.02
-40
-20
0
20
40
Temperature (°C)
60
80
100
-15
-40
-20
Figure 7. Voltage Accuracy
0
20
40
Temperature (°C)
60
80
100
Figure 8. Temperature Accuracy
0
-0.1
Current Accuracy Error (%)
-0.2
-0.3
-0.4
-0.5
-0.6
-40
-20
0
20
40
Temperature (°C)
60
80
100
Figure 9. Current Accuracy
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11 Power Supply Recommendation
11.1 Power Supply Decoupling
The battery connection on the BAT pin is used for two purposes:
• To supply power to the fuel gauge
• To provide an input for voltage measurement of the battery.
A capacitor of value of at least 1 µF should be connected between BAT and VSS. The capacitor should be placed
close to the gauge IC and have short traces to both the BAT pin and VSS.
The fuel gauge has an integrated LDO with an output on the VDD pin of approximately 1.8 V. A capacitor of value
at least 0.47 µF should be connected between the VDD pin and VSS. The capacitor should be placed close to the
gauge IC and have short traces to both the VDD pin and VSS.
12 Layout
12.1 Layout Guidelines
•
•
•
•
A capacitor of a value of at least 0.47 µF is connected between the VDD pin and VSS. The capacitor should be
placed close to the gauge IC and have short traces to both the VDD pin and VSS.
It is required to have a capacitor of at least 1.0 µF connect between the BAT pin and VSS if the connection
between the battery pack and the gauge BAT pin has the potential to pick up noise. The capacitor should be
placed close to the gauge IC and have short traces to both the VDD pin and VSS.
If the external pullup resistors on the SCL and SDA lines will be disconnected from the host during low-power
operation, it is recommend to use external 1-MΩ pulldown resistors to VSS to avoid floating inputs to the I2C
engine.
The value of the SCL and SDA pullup resistors should take into consideration the pullup voltage and the bus
capacitance. Some recommended values, assuming a bus capacitance of 10 pF, can be seen in Table 4.
Table 4. Recommended Values for SCL and SDA Pullup Resistors
VPU
RPU
•
•
•
•
•
•
18
1.8 V
3.3 V
Range
Typical
Range
Typical
400 Ω ≤ RPU ≤ 37.6 kΩ
10 kΩ
900 Ω ≤ RPU ≤ 29.2 kΩ
5.1 kΩ
If the GPOUT pin is not used by the host, the pin should still be pulled up to VDD with a 4.7-kΩ or 10-kΩ
resistor.
If the battery pack thermistor is not connected to the BIN pin, the BIN pin should be pulled down to VSS with a
10-kΩ resistor.
The BIN pin should not be shorted directly to VDD or VSS.
The actual device ground is pin 3 (VSS).
The SRP and SRN pins should be Kelvin connected to the RSENSE terminals. SRP to the battery pack side of
RSENSE and SRN to the system side of the RSENSE.
Kelvin connect the BAT pin to the battery PACKP terminal.
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12.2 Layout Example
Vpullup (do not pull to gauge VDD)
VDD (should be pulled up to gauge VDD)
RBIN
RSCL
RSDA
GPOUT
SDA
SDA
GPOUT
There is an internal pull down on
GPOUT
SCL
SCL
NC
VSS
BIN
NC
NC
VDD
SRP
BAT
SRN
If battery pack thermistor will not
be connected to BIN pin, a 10-k
pulldown resistor should be
connected to the BIN pin.
The BIN pin should not be shorted
directly to VDD or VSS.
CVDD
Place close
to gauge IC.
Trace to pin
and VSS
should be
short
CBAT
Kelvin connect BAT sense
line right at positive
battery terminal. The
leads must be short.
Via connects to Power Ground
RSENSE
VSYS
Battery Pack
PACK+
Use copper pours for
battery power path to
minimize IR losses
Li-Ion
Cell
TS
+
RTHERM
Kelvin connect SRP and
SRN connections right at
Rsense terminals
Protection
IC
PACKNFET
NFET
Figure 10. bq27441-G1 Board Layout
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13 Device and Documentation Support
13.1 Documentation Support
13.1.1 Related Documentation
• bq27441-G1 Technical Reference Manual (SLUUAC9)
• bq27441 EVM: System-Side Impedance Track™ Technology User's Guide (SLUUAP4)
• Quickstart Guide for bq27441-G1 (SLUUAP7)
• Single Cell Gas Gauge Circuit Design (SLUA456)
• Key Design Considerations for the bq27500 and bq27501 (SLUA439)
• Single Cell Impedance Track Printed-Circuit Board Layout Guide (SLUA457)
• ESD and RF Mitigation in Handheld Battery Electronics (SLUA460)
13.2 Trademarks
Impedance Track is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
13.3 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
13.4 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
14 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
BQ27441DRZR-G1A
ACTIVE
SON
DRZ
12
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ27
441A
BQ27441DRZR-G1B
ACTIVE
SON
DRZ
12
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ27
441B
BQ27441DRZT-G1A
ACTIVE
SON
DRZ
12
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ27
441A
BQ27441DRZT-G1B
ACTIVE
SON
DRZ
12
250
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
BQ27
441B
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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