BQ27500_08 [TI]
System-Side Impedance Track⑩ Fuel Gauge; 系统端Impedance Track ™电量计
| 型号： | BQ27500_08 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | System-Side Impedance Track⑩ Fuel Gauge |
| 文件： | 总39页 (文件大小：813K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
www.ti.com
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
1 INTRODUCTION
1.1 FEATURES
1.2 APPLICATIONS
•
Battery Fuel Gauge for 1-Series Li-Ion
Applications
•
•
•
•
•
Smartphones
PDAs
•
Resides on System Main Board
Digital Still and Video Cameras
Handheld Terminals
MP3 or Multimedia Players
–
Works With Embedded or Removable
Battery Packs
•
•
Two Varieties
–
bq27500: Uses PACK+, PACK–, and T
Battery Terminals
1.3 DESCRIPTION
–
bq27501: Works With Battery ID Resistor in
Battery Pack
The Texas Instruments bq27500/01 system-side
Li-Ion battery fuel gauge is
peripheral that provides fuel gauging for single-cell
Li-Ion battery packs. The device requires little system
microcontroller
bq27500/01 resides on the system main board, and
manages an embedded battery (non-removable) or a
removable battery pack.
a
microcontroller
Microcontroller Peripheral Provides:
–
–
Accurate Battery Fuel Gauging
Internal Temperature Sensor for System
Temperature Reporting
firmware
development.
The
–
–
–
–
Battery Low Interrupt Warning
Battery Insertion Indicator
Battery ID Detection
96 Bytes of Non-Volatile Scratch-Pad
FLASH
The bq27500/01 uses the patented Impedance
Track™ algorithm for fuel gauging, and provides
information such as remaining battery capacity
(mAh), state-of-charge (%), run-time to empty (min.),
battery voltage (mV), and temperature (°C).
•
Battery Fuel Gauge Based on Patented
Impedance Track™ Technology
–
Models the Battery Discharge Curve for
Accurate Time-to-Empty Predictions
Battery fuel gauging with the bq27500 requires only
PACK+ (P+), PACK– (P–), and Thermistor (T)
connections to
embedded battery. The bq27501 works with
identification resistors in battery packs to gauge
batteries of different fundamental chemistries and/or
significantly different rated capacities.
–
Automatically Adjusts for Battery Aging,
Battery Self-Discharge, and
a
removable battery pack or
Temperature/Rate Inefficiencies
–
Low-Value Sense Resistor (10 mΩ or Less)
•
•
I2C™ Interface for Connection to System
Microcontroller Port
12-Pin 2,5-mm × 4-mm SON Package
TYPICAL APPLICATION
Host System
LDO
Single-Cell Li-Ion
Battery Pack
Voltage
Sense
PACK+
RID
Battery
Low
Warning
RID
Sense*
Protection
IC
Temp
Sense
Power
Management
Controller
I2C
T
bq27500/1
CHG
DSG
Battery
Good
FETs
PACK–
Current
Sense
*bq27501 Only
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 document.
Impedance Track is a trademark of Texas Instruments.
I2C is a trademark of Philips Electronics.
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 © 2007–2008, Texas Instruments Incorporated
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
Contents
INTRODUCTION .......................................... 1
1
2
3
4.1 DATA COMMANDS .................................. 9
4.2 DATA FLASH INTERFACE ......................... 16
1.1 FEATURES ........................................... 1
1.2 APPLICATIONS ...................................... 1
1.3 DESCRIPTION ....................................... 1
DEVICE INFORMATION................................. 3
2.1 AVAILABLE OPTIONS ............................... 3
2.2 PIN DIAGRAMS ...................................... 3
2.3 TERMINAL FUNCTIONS............................. 3
ELECTRICAL SPECIFICATIONS ...................... 4
3.1 ABSOLUTE MAXIMUM RATINGS ................... 4
4.3
MANUFACTURER INFORMATION BLOCKS ...... 17
4.4 ACCESS MODES ................................... 17
4.5 SEALING/UNSEALING DATA FLASH.............. 17
4.6 DATA FLASH SUMMARY........................... 18
FUNCTIONAL DESCRIPTION ........................ 20
5.1 FUEL GAUGING .................................... 20
5.2 IMPEDANCE TRACK™ VARIABLES............... 20
5
5.3
DETAILED DESCRIPTION OF DEDICATED PINS. 23
3.2
RECOMMENDED OPERATING CONDITIONS...... 4
5.4 TEMPERATURE MEASUREMENT................. 26
5.5 OVERTEMPERATURE INDICATION............... 26
3.3 DISSIPATION RATINGS ............................. 5
3.4 POWER-ON RESET.................................. 5
5.6
CHARGING AND CHARGE-TERMINATION
INDICATION......................................... 26
3.5
INTERNAL TEMPERATURE SENSOR
CHARACTERISTICS ................................. 5
5.7 POWER MODES.................................... 27
5.8 POWER CONTROL................................. 29
5.9 AUTOCALIBRATION................................ 30
APPLICATION-SPECIFIC INFORMATION.......... 31
3.6 HIGH-FREQUENCY OSCILLATOR .................. 5
3.7 LOW-FREQUENCY OSCILLATOR .................. 5
3.8
INTEGRATING ADC (COULOMB COUNTER)
CHARACTERISTICS ................................. 6
ADC (TEMPERATURE AND CELL
6
6.1
BATTERY PROFILE STORAGE AND SELECTION 31
3.9
6.2
APPLICATION-SPECIFIC FLOW AND CONTROL. 31
MEASUREMENT) CHARACTERISTICS............. 6
7
8
COMMUNICATIONS
3.10 DATA FLASH MEMORY CHARACTERISTICS ...... 6
............................................................. 33
3.11 I2C-COMPATIBLE INTERFACE COMMUNICATION
TIMING CHARACTERISTICS ........................ 6
GENERAL DESCRIPTION .............................. 8
7.1 I2C INTERFACE..................................... 33
REFERENCE SCHEMATICS .......................... 34
8.1 SCHEMATIC ........................................ 34
4
2
Contents
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bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
www.ti.com
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
2 DEVICE INFORMATION
2.1 AVAILABLE OPTIONS
TAPE and
REEL
QUANTITY
FIRMWARE
PART NUMBER
COMMUNICATION
PACKAGE(2)
TA
VERSION(1)
FORMAT
bq27500DRZR
V1.06
3000
250
bq27500DRZT
bq27500DRZR-V100
V1.08
3000
250
12-pin, 2,5-mm × 4-mm
–40°C to 85°C
I2C
SON
bq27500DRZT-V100
bq27501DRZR
V1.08
3000
250
bq27501DRZT
(1) Ordering the device with the latest firmware version is recommended. To check the fiirmware revision and Errata list see SLUZ015
(2) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
2.2 PIN DIAGRAMS
12
11
10
9
1
2
3
4
5
6
BAT_GD
SCL
BAT_LOW
BI/TOUT
TS
12 BAT_GD
BAT_LOW
BI/TOUT
TS
1
2
3
4
5
6
SCL
11
SDA
SDA
NC
10
9
bq27501
bq27500
RID
BAT
BAT
SRN
SRP
8
SRN
SRP
8
VCC
VSS
VCC
VSS
7
7
2.3 TERMINAL FUNCTIONS
TERMINAL
TYPE(1)
DESCRIPTION
Cell-voltage measurement input. ADC input
bq27500 bq27501
NAME
BAT
PIN NO.
PIN NO.
4
4
I
Battery-good indicator. Active-low by default, though polarity can be configured through
the [BATG_POL] of Operation Configuration. Open-drain output
BAT_GD
BAT_LOW
BI/TOUT
12
1
12
1
O
Battery-low output indicator. Active-high by default, though polarity can be configured
through the [BATL_POL] in Operation Configuration. Push-pull output
O
Battery-insertion detection input. Power pin for pack thermistor network. Thermistor
multiplexer control pin. Open-drain I/O. Use with pullup resistor > 1 MΩ (1.8 MΩ typical).
2
2
I/O
NC
9
–
–
9
–
I
No connection (bq27500)
RID
Resistor ID input (bq27501). Analog input with current sourcing capabilities
Slave I2C serial communications clock input line for communication with system (master).
Open-drain I/O. Use with 10-kΩ pullup resistor (typical).
Slave I2C serial communications data line for communication with system (master).
Open-drain I/O. Use with 10-kΩ pullup resistor (typical).
SCL
SDA
SRN
SRP
11
10
8
11
10
8
I
I/O
IA
IA
Analog input pin connected to the internal coulomb counter where SRN is nearest the
System VSS connection. Connect to 5-mΩ to 20-mΩ sense resistor.
Analog input pin connected to the internal coulomb counter, where SRP is nearest the
PACK– connection. Connect to 5-mΩ to 20-mΩ sense resistor.
7
7
TS
3
5
3
5
IA
P
Pack thermistor voltage sense (use 103AT-type thermistor). ADC input
VCC
Processor power input. Decouple with 0.1-µF capacitor, minimum.
Device ground. Electrically connected to the IC exposed thermal pad (do not use thermal
pad as primary ground. Connect thermal pad to Vss via a PCB trace).
VSS
6
6
P
(1) I = Digital input, O = Digital output, I/O = Digital input/output, IA = Analog input, P = Power connection
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DEVICE INFORMATION
3
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
3 ELECTRICAL SPECIFICATIONS
3.1 ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)(1)
PARAMETER
VALUE
–0.3 to 2.75
–0.3 to 6
UNIT
V
VCC
VIOD
VBAT
VI
Supply voltage range
Open-drain I/O pins (BI/TOUT, SDA, SDL, BAT_GD)
BAT input pin
V
–0.3 to 6
Input voltage range to all other pins (TS, SRP, SRN, RID [bq27501 only], NC
[bq27500 only])
–0.3 to VCC + 0.3
V
Human-body model (HBM), BAT pin
Human-body model (HBM), all other pins
Operating free-air temperature range
Functional temperature range
1.5
ESD
kV
2
TA
–40 to 85
–40 to 100
–65 to 150
°C
°C
°C
TF
Tstg
Storage temperature range
(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.
3.2 RECOMMENDED OPERATING CONDITIONS
TA = 25°C, VCC = 2.5 V (unless otherwise noted)
PARAMETER
Supply voltage
TEST CONDITIONS
MIN
TYP
MAX UNIT
VCC
ICC
2.4
2.5
2.6
0.4
V
Fuel gauge in NORMAL mode.
ILOAD > Sleep Current
Normal operating-mode current
Low-power storage-mode current
Hibernate operating-mode current
100
15
1
µA
Fuel gauge in SLEEP mode.
ILOAD < Sleep Current
ISLP
µA
Fuel gauge in HIBERNATE mode.
ILOAD < Hibernate Current
IHIB
VOL
VOH(PP)
VOH(OD)
µA
Output voltage, low (SDA, BAT_LOW,
BI/TOUT)
IOL = 0.5 mA
V
Output voltage, high (BAT_LOW)
IOH = –1 mA
VCC – 0.5
VCC – 0.5
V
V
External pullup resistor connected to
VCC
Output voltage, high (SDA, SCL, BI/TOUT)
Input voltage, low (SDA, SCL)
Input voltage, low (BI/TOUT)
–0.3
–0.3
1.2
0.6
0.6
6
VIL
BAT INSERT CHECK MODE active
BAT INSERT CHECK MODE active
V
Input voltage, high (SDA, SCL)
Input voltage, high (BI/TOUT)
VIH(OD)
1.2
6
CIN
Input capacitance (SDA, SCL, BI/TOUT)
Input voltage range (TS, RID [bq27501 only])
Input voltage range (BAT)
35
pF
V
VA1
VA2
VA3
tPUCD
VSS – 0.125
VSS – 0.125
VSS – 0.125
2
5
V
Input voltage range (SRP, SRN)
Power-up communication delay
0.125
V
250
ms
4
ELECTRICAL SPECIFICATIONS
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bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
www.ti.com
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
3.3 DISSIPATION RATINGS
T
A ≤ 40°C
DERATING FACTOR
RθJA
PACKAGE
POWER RATING
TA > 40°C
12-pin DRZ(1)
482 mW
5.67 mW/°C
176°C/W
(1) This data is based on using a four-layer JEDEC high-K board with the exposed die pad connected to a Cu pad on the board. The board
pad is connected to the ground plane by a 2- × 2-via matrix.
3.4 POWER-ON RESET
TA = –40°C to 85°C, typical values at TA = 25°C and VBAT = 3.6 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
2.09
45
TYP
2.2
MAX
2.31
185
UNIT
V
VIT+
Positive-going battery voltage input at VCC
Hysteresis voltage
VHYS
115
mV
3.5 INTERNAL TEMPERATURE SENSOR CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN TYP
MAX
UNIT
GTEMP
Temperature sensor voltage gain
–2
mV/°C
3.6 HIGH-FREQUENCY OSCILLATOR
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
fOSC
Operating frequency
2.097
MHz
TA = 0°C to 60°C
–2% 0.38%
–3% 0.38%
2%
3%
fEIO
Frequency error(1) (2)
Start-up time(3)
TA = –20°C to 70°C
TA = –40°C to 85°C
–4.5% 0.38% 4.5%
2.5
tSXO
5
ms
(1) The frequency error is measured from 2.097 MHz.
(2) The frequency drift is included and measured from the trimmed frequency at VCC = 2.5 V, TA = 25°C.
(3) The start-up time is defined as the time it takes for the oscillator output frequency to be within ±3% of typical oscillator frequency.
3.7 LOW-FREQUENCY OSCILLATOR
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
32.768
0.25%
0.25%
0.25%
MAX UNIT
kHz
fLOSC
Operating frequency
TA = 0°C to 60°C
–1.5%
–2.5%
–4%
1.5%
fLEIO
Frequency error(1) (2)
Start-up time(3)
TA = –20°C to 70°C
TA = –40°C to 85°C
2.5%
4%
tLSXO
500
µs
(1) The frequency drift is included and measured from the trimmed frequency at VCC = 2.5 V, TA = 25°C.
(2) The frequency error is measured from 32.768 kHz.
(3) The start-up time is defined as the time it takes for the oscillator output frequency to be within ±3% of typical oscillator frequency.
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ELECTRICAL SPECIFICATIONS
5
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
3.8 INTEGRATING ADC (COULOMB COUNTER) CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Input voltage range (VSR = V(SRN) – V(SRP)
Conversion time
TEST CONDITIONS
MIN
TYP
MAX
UNIT
V
VSR
)
–0.125
0.125
tSR_CONV
Single conversion
1
s
Resolution
14
15
bits
µV
VSR_OS
INL
Input offset
10
Integral nonlinearity error
Effective input resistance(1)
Input leakage current(1)
±0.007 ±0.034
% FSR
MΩ
µA
ZSR_IN
ISR_LKG
2.5
0.3
(1) Specified by design. Not tested in production.
3.9 ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Input voltage range
Conversion time
Resolution
TEST CONDITIONS
MIN
TYP
MAX
1
UNIT
V
VADC_IN
–0.2
tADC_CONV
125
15
ms
14
bits
mV
VADC_OS
ZADC1
Input offset
1
Effective input resistance (TS, RID
[bq27501 only])(1)
8
8
MΩ
bq27500/1 not measuring cell voltage
bq27500/1 measuging cell voltage
MΩ
kΩ
µA
ZADC2
Effective input resistance (BAT)(1)
Input leakage current(1)
100
IADC_LKG
0.3
(1) Specified by design. Not tested in production.
3.10 DATA FLASH MEMORY CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
Data retention(1)
Flash-programming write cycles(1)
Word programming time(1)
Flash-write supply current(1)
TEST CONDITIONS
MIN
10
TYP
MAX
UNIT
Years
Cycles
ms
tON
20,000
tWORDPROG
ICCPROG
2
5
10
mA
(1) Specified by design. Not production tested
3.11 I2C-COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
SCL/SDA rise time
TEST CONDITIONS
MIN TYP
MAX
1
UNIT
µs
tr
tf
SCL/SDA fall time
300
ns
tw(H)
tw(L)
tsu(STA)
td(STA)
tsu(DAT)
SCL pulse duration (high)
SCL pulse duration (low)
Setup for repeated start
Start to first falling edge of SCL
Data setup time
4
4.7
4.7
4
µs
µs
µs
µs
250
ns
6
ELECTRICAL SPECIFICATIONS
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bq27501
System-Side Impedance Track™ Fuel Gauge
www.ti.com
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
I2C-COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS (continued)
TA = –40°C to 85°C, 2.4 V < VCC < 2.6 V; typical values at TA = 25°C and VCC = 2.5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Receive mode
Transmit mode
MIN TYP
MAX
UNIT
0
300
4
th(DAT)
Data hold time
ns
tsu(STOP)
t(BUF)
Setup time for stop
µs
µs
kHz
s
Bus free time between stop and start
Clock frequency
4.7
10
fSCL
100
tBUSERR
Bus error time-out
17.3
21.2
Figure 3-1. I2C-Compatible Interface Timing Diagrams
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ELECTRICAL SPECIFICATIONS
7
bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
4 GENERAL DESCRIPTION
The bq27500/1 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-of-charge (SOC), time-to-empty (TTE) and time-to-full (TTF).
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 bq27500/1 control and
status registers, as well as its data flash locations. Commands are sent from system to gauge using the
bq27500/1 I2C serial communications engine, and can be executed during application development, pack
manufacture, or end-equipment operation.
Cell information is stored in the bq27500/1 in non-volatile flash memory. Many of these data flash
locations are accessible during application development. They cannot be accessed directly during
end-equipment operation. Access to these locations is achieved by either use of the bq27500/1
companion evaluation software, through individual commands, or through a sequence of data-flash-access
commands. To access a desired data flash location, the correct data flash subclass and offset must be
known.
The bq27500/1 provides 96 bytes of user-programmable data flash memory, partitioned into three 32-byte
blocks: Manufacturer Info Block A, Manufacturer Info Block B, and Manufacturer Info Block C. This
data space is accessed through a data flash interface. For specifics on accessing the data flash, see
Section 4.3, Manufacturer Information Blocks.
The key to the high-accuracy fuel gauging prediction of the bq27500/1 is Texas Instruments' proprietary
Impedance Track™ algorithm. This algorithm uses cell measurements, characteristics, and properties to
create state-of-charge predictions that can achieve less than 1% error across a wide variety of operating
conditions and over the lifetime of the battery.
The bq27500/1 measures charge/discharge activity by monitoring the voltage across a small-value series
sense resistor (5 mΩ to 20 mΩ, typ.) located between the system Vss and the battery PACK– terminal.
When a cell is attached to the bq27500/1, cell impedance is computed, based on cell current, cell
open-circuit voltage (OCV), and cell voltage under loading conditions.
The bq27500/1 must use an NTC thermistor Semitec 103AT for temperature measurement, or can also
be configured to use its internal temperature sensor. The bq27500/1 uses temperature to monitor the
battery-pack environment, which is used for fuel gauging and cell protection functionality.
To minimize power consumption, the bq27500/1 has several power modes: NORMAL, SLEEP,
HIBERNATE, and BAT INSERT CHECK. The bq27500/1 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 can be found in Section 5.7, Power Modes.
NOTE
FORMATTING CONVENTIONS IN THIS DOCUMENT:
Commands: italics with parentheses and no breaking spaces, e.g., RemainingCapacity( ).
Data flash: italics, bold, and breaking spaces, e.g., Design Capacity
Register bits and flags: brackets and italics, e.g., [TDA]
Data flash bits: brackets, italics and bold, e.g., [LED1]
Modes and states: ALL CAPITALS, e.g., UNSEALED mode.
8
GENERAL DESCRIPTION
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bq27501
System-Side Impedance Track™ Fuel Gauge
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SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
4.1 DATA COMMANDS
4.1.1 STANDARD DATA COMMANDS
The bq27500/1 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 4-1. 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 options for transferring data, such as spooling, are described in Section 7, I2C Interface.
Standard commands are accessible in NORMAL operation. Read/write permissions depend on the active
access mode, SEALED or UNSEALED (for details on the SEALED and UNSEALED states, see
Section 4.4, Access Modes).
Table 4-1. Standard Commands
NAME
COMMAND CODE
0x00 / 0x01
0x02 / 0x03
0x04 / 0x05
0x06 / 0x07
0x08 / 0x09
0x0a / 0x0b
0x0c / 0x0d
0x0e / 0x0f
0x10 / 0x11
0x12 / 0x13
0x14 / 0x15
0x16 / 0x17
0x18 / 0x19
0x1a / 0x1b
0x1c / 0x1d
0x1e / 0x1f
0x20 / 0x21
0x22 / 0x23
0x24 / 0x25
0x26 / 0x27
0x28 / 0x29
0x2a / 0x2b
0x2c / 0x2d
UNITS
N/A
SEALED ACCESS
UNSEALED ACCESS
Control( )
AtRate( )
CNTL
AR
R/W
R/W
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
mA
AtRateTimeToEmpty( )
Temperature( )
ARTTE
TEMP
VOLT
FLAGS
NAC
FAC
RM
Minutes
0.1 K
mV
R
Voltage( )
R
Flags( )
N/A
R
NominalAvailableCapacity( )
FullAvailableCapacity( )
RemainingCapacity( )
FullChargeCapacity( )
AverageCurrent( )
TimeToEmpty( )
mAh
R
mAh
R
mAh
R
FCC
AI
mAh
R
mA
R
TTE
Minutes
Minutes
mA
R
TimeToFull( )
TTF
R
StandbyCurrent( )
StandbyTimeToEmpty( )
MaxLoadCurrent( )
MaxLoadTimeToEmpty( )
AvailableEnergy( )
AveragePower( )
SI
R
STTE
MLI
Minutes
mA
R
R
MLTTE
AE
Minutes
mWh
mW
R
R
AP
R
TimeToEmptyAtConstantPower( )
Reserved
TTECP
RSVD
CC
Minutes
N/A
R
R
CycleCount( )
Counts
%
R
StateOfCharge( )
SOC
R
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bq27500
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System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
4.1.1.1 Control( ): 0x00/0x01
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 bq27500/1 during normal operation and additional features when the bq27500/1 is in
different access modes, as described in Table 4-2.
Table 4-2. Control( ) Subcommands
CNTL
DATA
SEALED
ACCESS
CNTL FUNCTION
CONTROL_STATUS
DESCRIPTION
0x0000
0x0001
0x0002
0x0003
Yes
Yes
Yes
Yes
Reports the status of DF checksum, hibernate, IT, etc.
Reports the device type (eg: "bq27500")
DEVICE_TYPE
FW_VERSION
HW_VERSION
Reports the firmware version on the device type
Reports the hardware version of the device type
Enables a data flash checksum to be generated and
reports on a read
DF_CHECKSUM
0x0004
No
RESET_DATA
Reserved
0x0005
0x0006
0x0007
Yes
No
Returns reset data
Not to be used
PREV_MACWRITE
Yes
Returns previous MAC command code
Reports the chemical identifier of the Impedance Track™
configuration
CHEM_ID
0x0008
Yes
BOARD_OFFSET
CC_INT_OFFSET
WRITE_OFFSET
SET_HIBERNATE
CLEAR_HIBERNATE
SEALED
0x0009
0x000a
0x000b
0x0011
0x0012
0x0020
0x0021
0x0022
0x0040
0x0041
No
No
No
Yes
Yes
No
No
No
No
No
Forces the device to measure and store the board offset
Forces the device to measure the internal CC offset
Forces the device to store the internal CC offset
Forces CONTROL_STATUS [HIBERNATE] to 1
Forces CONTROL_STATUS [HIBERNATE] to 0
Places the bq27500/1 in SEALED access mode
Enables the Impedance Track™ algorithm
Reports the instruction flash checksum
IT_ENABLE
IF_CHECKSUM
CAL_MODE
Places the bq27500/1 in calibration mode
RESET
Forces a full reset of the bq27500/1
4.1.1.1.1 CONTROL_STATUS: 0x0000
Instructs the fuel gauge to return status information to control addresses 0x00/0x01. The status word
includes the following information.
Table 4-3. CONTROL_STATUS Bit Definitions
Flags( )
High byte
Low byte
bit7
–
bit6
FAS
bit5
SS
–
bit4
CSV
bit3
CCA
bit2
BCA
bit1
–
bit0
–
–
HIBERNATE
SLEEP
LDMD
RUP_DIS
VOK
QEN
FAS = Status bit indicating the bq27500/1 is in FULL ACCESS SEALED state. Active when set.
SS = Status bit indicating the bq27500/1 is in SEALED state. Active when set.
CSV = Status bit indicating a valid data flash checksum has been generated. Active when set.
CCA = Status bit indicating the bq27500/1 coulomb counter calibration routine is active. Active when set.
BCA = Status bit indicating the bq27500/1 board calibration routine is active. Active when set.
HIBERNATE = Status bit indicating a request for entry into HIBERNATE from SLEEP mode. True when set. Default is 0.
SLEEP = Status bit indicating the bq27500/1 is in SLEEP mode. True when set.
LDMD = Status bit indicating the bq27500/1 Impedance Track™ algorithm is using constant-power mode. True when set. Default is 0
(constant-current mode).
RUP_DIS = Status bit indicating the bq27500/1 Ra table updates are disabled. Updates disabled when set.
VOK = Status bit indicating the bq27500/1 voltages are okay for Qmax. True when set.
QEN = Status bit indicating the bq27500/1 Qmax updates enabled. True when set.
10
GENERAL DESCRIPTION
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4.1.1.1.2 DEVICE_TYPE: 0x0001
Instructs the fuel gauge to return the device type to addresses 0x00/0x01.
4.1.1.1.3 FW_VERSION: 0x0002
Instructs the fuel gauge to return the firmware version to addresses 0x00/0x01.
4.1.1.1.4 HW_VERSION: 0x0003
Instructs the fuel gauge to return the hardware version to addresses 0x00/0x01.
4.1.1.1.5 DF_CHECKSUM: 0x0004
Instructs the fuel gauge to compute the checksum of the data flash memory. Once the checksum has
been calculated and stored, CONTROL_STATUS [CVS] is set. The checksum value is written and
returned to addresses 0x00/0x01 (UNSEALED mode only). The checksum is not calculated in SEALED
mode; however, the checksum value can still be read.
4.1.1.1.6 RESET_DATA: 0x0005
Instructs the fuel gauge to return the reset data to addresses 0x00/0x01, with the low byte (0x00) being
the number of full resets and the high byte (0x01) the number of partial resets.
4.1.1.1.7 PREV_MACWRITE: 0x0007
Instructs the fuel gauge to return the previous command written to addresses 0x00/0x01.
4.1.1.1.8 CHEM_ID: 0x0008
Instructs the fuel gauge to return the chemical identifier for the Impedance Track™ configuration to
addresses 0x00/0x01.
4.1.1.1.9 BOARD_OFFSET: 0x0009
Instructs the fuel gauge to compute the coulomb counter offset with internal short and then without internal
short applied across the SR inputs. The difference between the two measurements is the board offset.
After a delay of approximately 32 seconds, this offset value is returned to addresses 0x00/0x01 and
written to data flash. The coulomb counter offset is also written to data flash. The CONROL STATUS
[BCA] is also set. The user must prevent any charge or discharge current from flowing during the process.
This function is only available when the fuel gauge is UNSEALED. When SEALED, this command only
reads back the board-offset value stored in data flash.
4.1.1.1.10 CC_INT_OFFSET: 0x000A
Instructs the fuel gauge to compute the coulomb counter offset with internal short applied across the SR
inputs. The offset value is returned to addresses 0x00/0x01 after a delay of approximately 16 seconds.
This function is only available when the fuel gauge is UNSEALED. When SEALED, this command only
reads back the CC_INT_OFFSET value stored in data flash.
4.1.1.1.11 WRITE_OFFSET: 0x000B
Control data of 0x000b causes the fuel gauge to write the coulomb counter offset to data flash.
4.1.1.1.12 SET_HIBERNATE: 0x0011
Instructs the fuel gauge to force the CONTROL_STATUS [HIBERNATE] bit to 1. This allows the gauge to
enter the HIBERNATE power mode after the transition to SLEEP power state is detected. The
[HIBERNATE] bit is automatically cleared upon exiting from HIBERNATE mode.
4.1.1.1.13 CLEAR_HIBERNATE: 0x0012
Instructs the fuel gauge to force the CONTROL_STATUS [HIBERNATE] bit to 0. This prevents the gauge
from entering the HIBERNATE power mode after the transition to the SLEEP power state is detected. It
can also be used to force the gauge out of HIBERNATE mode.
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System-Side Impedance Track™ Fuel Gauge
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4.1.1.1.14 SEALED: 0x0020
Instructs the fuel gauge to transition from the UNSEALED state to the SEALED state. The fuel gauge must
always be set to the SEALED state for use in end equipment.
4.1.1.1.15 IT_ENABLE: 0x0021
This command forces the fuel gauge to begin the Impedance Track™ algorithm, sets the active
UpdateStatus n location to 0x01 and causes the [VOK] and [QEN] flags to be set in the
CONTROL_STATUS register. [VOK] is cleared if the voltages are not suitable for a Qmax update. Once
set, [QEN] cannot be cleared. This command is only available when the fuel gauge is UNSEALED.
4.1.1.1.16 IF_CHECKSUM: 0x0022
This command instructs the fuel gauge to compute the instruction flash checksum. In UNSEALED mode,
the checksum value is returned to addresses 0x00/0x01. The checksum is not calculated in SEALED
mode; however, the checksum value can still be read.
4.1.1.1.17 CAL_MODE: 0x0040
This command instructs the fuel gauge to enter calibration mode. This command is only available when
the fuel gauge is UNSEALED.
4.1.1.1.18 RESET: 0x0041
This command instructs the fuel gauge to perform a full reset. This command is only available when the
fuel gauge is UNSEALED.
4.1.1.2 AtRate( ): 0x02/0x03
The AtRate( ) read-/write-word function is the first half of a two-function command set used to set the
AtRate value used in calculations made by the AtRateTimeToEmpty( ) function. The AtRate( ) units are in
mA.
The AtRate( ) value is a signed integer, with negative values interpreted as a discharge current value. The
AtRateTimeToEmpty( ) function returns the predicted operating time at the AtRate value of discharge. The
default value for AtRate( ) is zero and forces AtRate( ) to return 65,535. Both the AtRate( ) and
AtRateTimeToEmpty( ) commands must only be used in NORMAL mode.
4.1.1.3 AtRateTimeToEmpty( ): 0x04/0x05
This read-word function returns an unsigned integer value of the predicted remaining operating time if the
battery is discharged at the AtRate( ) value in minutes with a range of 0 to 65,534. A value of 65,535
indicates AtRate( ) = 0. The fuel gauge updates AtRateTimeToEmpty( ) within 1 s after the system sets the
AtRate( ) value. The fuel gauge automatically updates AtRateTimeToEmpty( ) based on the AtRate( )
value every 1 s. Both the AtRate( ) and AtRateTimeToEmpty( ) commands must only be used in NORMAL
mode.
4.1.1.4 Temperature( ): 0x06/0x07
This read-word function returns an unsigned integer value of the temperature in units of 0.1 K measured
by the fuel gauge and has a range of 0 to 6,553.5 K.
4.1.1.5 Voltage( ): 0x08/0x09
This read-word function returns an unsigned integer value of the measured cell-pack voltage in mV with a
range of 0 to 6,000 mV.
4.1.1.6 Flags( ): 0x0a/0x0b
This read-word function returns the contents of the fuel-gauge status register, depicting the current
operating status.
12
GENERAL DESCRIPTION
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Table 4-4. Flags Bit Definitions
bit7
OTC
–
bit6
OTD
–
bit5
–
bit4
–
bit3
bit2
bit1
FC
bit0
CHG
DSG
High byte
Low byte
CHG_INH
BAT_DET
XCHG
SOC1
OCV_GD
WAIT_ID
SOCF
OTC = Overtemperature in charge condition is detected. True when set.
OTD = Overtemperature in discharge condition is detected. True when set.
CHG_INH = Charge inhibit: unable to begin charging (temperature outside the range [Charge Inhibit Temp Low, Charge Inhibit Temp
High]). True when set.
XCHG = Charge suspend alert (temperature outside the range [Suspend Temp Low, Suspend Temp High]). True when set.
FC = Fully charged. Set when charge termination condition is met. True when set.
CHG = (Fast) charging allowed. True when set.
OCV_GD = Good OCV measurement taken. True when set.
WAIT_ID = Waiting to identify inserted battery. True when set.
BAT_DET = Battery detected. True when set.
SOC1 = State-of-charge threshold 1 (SOC1 Set Threshold) reached. True when set.
SOCF = State-of-charge threshold final (SOCF Set Threshold) reached. True when set.
DSG = Discharging detected. True when set.
4.1.1.7 NominalAvailableCapacity( ): 0x0c/0x0d
This read-only command pair returns the uncompensated (no or light load) battery capacity remaining.
Units are mAh per LSB.
4.1.1.8 FullAvailableCapacity( ): 0x0e/0x0f
This read-only command pair returns the uncompensated (no or light load) capacity of the battery when
fully charged. Units are mAh per LSB. FullAvailableCapacity( ) is updated at regular intervals, as specified
by the IT algorithm.
4.1.1.9 RemainingCapacity( ): 0x10/0x11
This read-only command pair returns the compensated battery capacity remaining. Units are mAh per
LSB.
4.1.1.10 FullChargeCapacity( ): 0x12/13
This read-only command pair returns the compensated capacity of the battery when fully charged. Units
are mAh per LSB. FullChargeCapacity( ) is updated at regular intervals, as specified by the IT algorithm.
4.1.1.11 AverageCurrent( ): 0x14/0x15
This read-only command pair returns a signed integer value that is the average current flow through the
sense resistor. It is updated every 1 second. Units are mA per LSB.
4.1.1.12 TimeToEmpty( ): 0x16/0x17
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
present rate of discharge, in minutes. A value of 65,535 indicates battery is not being discharged.
4.1.1.13 TimeToFull( ): 0x18/0x19
This read-only function returns an unsigned integer value of predicted remaining time until the battery
reaches full charge, in minutes, based upon AverageCurrent( ). The computation accounts for the taper
current time extension from the linear TTF computation based on a fixed AverageCurrent( ) rate of charge
accumulation. A value of 65,535 indicates the battery is not being charged.
4.1.1.14 StandbyCurrent( ): 0x1a/0x1b
This read-only function returns a signed integer value of the measured standby current through the sense
resistor. The StandbyCurrent( ) is an adaptive measurement. Initially it reports the standby current
programmed in Initial Standby, and after spending several seconds in standby, reports the measured
standby current.
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System-Side Impedance Track™ Fuel Gauge
SLUS785D–SEPTEMBER 2007–REVISED APRIL 2008
www.ti.com
The register value is updated every 1 second when the measured current is above the Deadband (3-mA
default) and is less than or equal to 2 × Initial Standby. The first and last values that meet this criteria are
not averaged in, because they may not be stable values. To approximate a 1-minute time constant, each
new StandbyCurrent( ) value is computed as follows:
StandbyCurrent( )NEW = (239/256) × StandbyCurrent( )OLD + (17/256) × AverageCurrent( ).
4.1.1.15 StandbyTimeToEmpty( ): 0x1c/0x1d
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
standby rate of discharge, in minutes. The computation uses Nominal Available Capacity (NAC), the
uncompensated remaining capacity, for this computation. A value of 65,535 indicates battery is not being
discharged.
4.1.1.16 MaxLoadCurrent( ): 0x1e/0x1f
This read-only function returns a signed integer value, in units of mA, of the maximum load conditions.
The MaxLoadCurrent( ) is an adaptive measurement which is initially reported as the maximum load
current programmed in Initial Max Load Current. If the measured current is ever greater than Initial Max
Load Current, then MaxLoadCurrent( ) updates to the new current. MaxLoadCurrent( ) is reduced to the
average of the previous value and Initial Max Load Current whenever the battery is charged to full after
a previous discharge to an SOC less than 50%. This prevents the reported value from maintaining an
unusually high value.
4.1.1.17 MaxLoadTimeToEmpty( ): 0x20/0x21
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
maximum load current discharge rate, in minutes. A value of 65,535 indicates that the battery is not being
discharged.
4.1.1.18 AvailableEnergy( ): 0x22/0x23
This read-only function returns an unsigned integer value of the predicted charge or energy remaining in
the battery. The value is reported in units of mWh.
4.1.1.19 AveragePower( ): 0x24/0x25
This read-word function returns an signed integer value of the average power during battery charging and
discharging. A value of 0 indicates that the battery is not being discharged. The value is reported in units
of mW.
4.1.1.20 TimeToEmptyAtConstantPower( ): 0x26/0x27
This read-only function returns an unsigned integer value of the predicted remaining operating time if the
battery is discharged at the AveragePower( ) value in minutes. A value of 65,535 indicates
AveragePower( ) = 0. The fuel gauge automatically updates TimeToEmptyatContantPower( ) based on the
AveragePower( ) value every 1 s.
4.1.1.21 CycleCount( ): 0x2a/0x2b
This read-only function returns an unsigned integer value of the number of cycles the battery has
experienced with a range of 0 to 65,535. One cycle occurs when accumulated discharge ≥ CC Threshold.
4.1.1.22 StateOfCharge( ): 0x2c/0x2d
This read-only function returns an unsigned integer value of the predicted remaining battery capacity
expressed as a percentage of FullChargeCapacity( ), with a range of 0 to 100%.
4.1.2 EXTENDED DATA COMMANDS
Extended 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 commands bytes for a given extended command ranges in size from single to
multiple bytes, as specified in Table 4-5. For details on the SEALED and UNSEALED states, see
Section 4.4, Access Modes.
14
GENERAL DESCRIPTION
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Table 4-5. Extended Data Commands
COMMAND
CODE
SEALED
UNSEALED
NAME
UNITS
ACCESS(1) (2)
ACCESS(1) (2)
Reserved
RSVD
DCAP
0x34...0x3b
0x3c / 0x3d
0x3e
N/A
mAh
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
R
R
R
R
DesignCapacity( )
DataFlashClass( ) (2)
DataFlashBlock( ) (2)
BlockData( )
DFCLS
N/A
R/W
R
R/W
R/W
R/W
R/W
R/W
R
DFBLK
0x3f
DFD
0x40…0x5f
0x60
BlockDataCheckSum( )
BlockDataControl( )
DeviceNameLength( )
DeviceName( )
DFDCKS
DFDCNTL
DNAMELEN
DNAME
APPSTAT
RSVD
R/W
N/A
R
0x61
0x62
0x63...0x69
0x6a
R
R
ApplicationStatus( )
Reserved
R
R
0x6b...0x7f
R
R
(1) SEALED and UNSEALED states are entered via commands to CNTL 0x00/0x01.
(2) In sealed mode, data flash CANNOT be accessed through commands 0x3e and 0x3f.
4.1.2.1 DesignCapacity( ): 0x3c/0x3d
SEALED and UNSEALED Access: This command returns the theoretical or nominal capacity of a new
pack. The value is stored in Design Capacity and is expressed in mAh. This is intended to be the
theoretical or nominal capacity of a new pack, but has no bearing on the operation of the fuel gauge
functionality.
4.1.2.2 DataFlashClass( ): 0x3e
UNSEALED Access: This command sets the data flash class to be accessed. The class to be accessed
must be entered in hexadecimal.
SEALED Access: This command is not available in SEALED mode.
4.1.2.3 DataFlashBlock( ): 0x3f
UNSEALED Access: This command sets the data flash block to be accessed. When 0x00 is written to
BlockDataControl( ), DataFlashBlock( ) holds the block number of the data flash to be read or written.
Example: writing a 0x00 to DataFlashBlock( ) specifies access to the first 32-byte block, a 0x01 specifies
access to the second 32-byte block, and so on.
SEALED Access: This command directs which data flash block is accessed by the BlockData( ) command.
Writing a 0x00 to DataFlashBlock( ) specifies that the BlockData( ) command transfers authentication data.
Issuing a 0x01, 0x02, or 0x03 instructs the BlockData( ) command to transfer Manufacturer Info Block A,
B, or C, respectively.
4.1.2.4 BlockData( ): 0x40…0x5f
This command range is the 32-byte data block used to access Manufacturer Info Block A, B, or C.
UNSEALED access is read/write. SEALED access is read only.
4.1.2.5 BlockDataChecksum( ): 0x60
UNSEALED Access: This byte contains the checksum on the 32 bytes of block data read or written to
data flash. The least-significant byte of the sum of the data bytes written must be complemented
([255 – x], for x the least-significant byte) before being written to 0x60.
SEALED Access: This byte contains the checksum for the 32 bytes of block data written to Manufacturer
Info Block A, B, or C. The least-significant byte of the sum of the data bytes written must be
complemented ([255 – x], for x the least-significant byte) before being written to 0x60.
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4.1.2.6 BlockDataControl( ): 0x61
UNSEALED Access: This command is used to control data flash access mode. Writing 0x00 to this
command enables BlockData( ) to access general data flash. Writing a 0x01 to this command enables
SEALED mode operation of DataFlashBlock( ).
SEALED Access: This command is not available in SEALED mode.
4.1.2.7 DeviceNameLength( ): 0x62
UNSEALED and SEALED Access: This byte contains the length of the Device Name.
4.1.2.8 DeviceName( ): 0x63…0x69
UNSEALED and SEALED Access: This block contains the device name that is programmed in Device
Name.
4.1.2.9 ApplicationStatus( ): 0x6a
This byte function allows the system to read the bq27500/1 Application Status data flash location. See
Table 6-1 for specific bit definitions.
4.1.2.10 Reserved — 0x6b–0x7f
4.2 DATA FLASH INTERFACE
4.2.1 ACCESSING THE DATA FLASH
The bq27500/1 data flash is a non-volatile memory that contains bq27500/1 initialization, default, cell
status, calibration, configuration, and user information. The data flash can be accessed in several different
ways, depending on what mode the bq27500/1 is operating in and what data is being accessed.
Commonly accessed data flash memory locations, frequently read by a system, are conveniently
accessed through specific instructions, already described in Section 4.1, DATA COMMANDS. These
commands are available when the bq27500/1 is either in UNSEALED or SEALED modes.
Most data flash locations, however, are only accessible in UNSEALED mode by use of the bq27500/1
evaluation software or by data flash block transfers. These locations must be optimized and/or fixed during
the development and manufacture processes. They become part of a golden image file and can then be
written to multiple battery packs. Once established, the values generally remain unchanged during
end-equipment operation.
To access data flash locations individually, the block containing the desired data flash location(s) must be
transferred to the command register locations, where the information can be read to the system or
changed directly. This is accomplished by sending the setup command BlockDataControl( ) (0x61) with
data 0x00. Up to 32 bytes of data can be read directly from the BlockData( ) (0x40…0x5f), externally
altered, then rewritten to the BlockData( ) command space. Alternatively, specific locations can be read,
altered, and rewritten if their corresponding offsets are used to index into the BlockData( ) command
space. Finally, the data residing in the command space is transferred to data flash, once the correct
checksum for the whole block is written to BlockDataChecksum( ) (0x60).
Occasionally, a data flash CLASS is larger than the 32-byte block size. In this case, the DataFlashBlock( )
command is used to designate in which 32-byte block the desired information resides. The correct
command address is then given by 0x40 + offset modulo 32. For example, to access Terminate Voltage
in the Fuel Gauging class, DataFlashClass( ) is issued 80 (0x50) to set the class. Because the offset is 48,
it must reside in the second 32-byte block. Hence, DataFlashBlock( ) is issued 0x01 to set the block offset,
and the offset used to index into the BlockData( ) memory area is 0x40 + 48 modulo 32 = 0x40 + 16 =
0x40 + 0x10 = 0x50.
Reading and writing subclass data are block operations up to 32 bytes in length. If during a write the data
length exceeds the maximum block size, then the data is ignored.
16
GENERAL DESCRIPTION
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None of the data written to memory are bounded by the bq27500/1– the values are not rejected by the
fuel gauge. Writing an incorrect value may result in hardware failure due to firmware program
interpretation of the invalid data. The written data is persistent, so a power-on reset does resolve the fault.
4.3 MANUFACTURER INFORMATION BLOCKS
The bq27500/1 contains 96 bytes of user programmable data flash storage: Manufacturer Info Block A,
Manufacturer Info Block B, Manufacturer Info Block C. The method for accessing these memory
locations is slightly different, depending on whether the device is in UNSEALED or SEALED modes.
When in UNSEALED mode and when and 0x00 has been written to BlockDataControl( ), accessing the
manufacturer information blocks is identical to accessing general data flash locations. First, a
DataFlashClass( ) command is used to set the subclass, then a DataFlashBlock( ) command sets the
offset for the first data flash address within the subclass. The BlockData( ) command codes contain the
referenced data flash data. When writing the data flash, a checksum is expected to be received by
BlockDataChecksum( ). Only when the checksum is received and verified is the data actually written to
data flash.
As an example, the data flash location for Manufacturer Info Block B is defined as having a Subclass =
58 and an Offset = 32 through 63 (32 byte block). The specification of Class = System Data is not needed
to address Manufacturer Info Block B, but is used instead for grouping purposes when viewing data
flash info in the bq27500/1 evaluation software.
When in SEALED mode or when 0x01 BlockDataControl( ) does not contain 0x00, data flash is no longer
available in the manner used in UNSEALED mode. Rather than issuing subclass information, a
designated manufacturer information block is selected with the DataFlashBlock( ) command. Issuing a
0x01, 0x02, or 0x03 with this command causes the corresponding information block (A, B, or C,
respectively) to be transferred to the command space 0x40…0x5f for editing or reading by the system.
Upon successful writing of checksum information to BlockDataChecksum( ), the modified block is returned
to data flash. Note: Manufacturer Info Block A is read-only when in SEALED mode.
4.4 ACCESS MODES
The bq27500/1 provides three security modes (FULL ACCESS, UNSEALED, and SEALED) that control
data flash access permissions, according to Table 4-6. Public Access refers to those data flash locations,
specified in Table 4-7, that are accessible to the user. Private Access refers to reserved data flash
locations used by the bq27500/1 system. Care should be taken to avoid writing to Private data flash
locations when performing block writes in FULL ACCESS mode, by following the procedure outlined in
Section 4.2.1, ACCESSING THE DATA FLASH.
Table 4-6. Data Flash Access
Security Mode
FULL ACCESS
UNSEALED
SEALED
DF – Public Access
DF – Private Access
R/W
R/W
R
R/W
R/W
N/A
Although FULL ACCESS and UNSEALED modes appear identical, only FULL ACCESS allows the
bq27500/1 to write access-mode transition keys.
4.5 SEALING/UNSEALING DATA FLASH
The bq27500/1 implements a key-access scheme to transition between SEALED, UNSEALED, and
FULL-ACCESS modes. Each transition requires that a unique set of two keys be sent to the bq27500/1
via the Control( ) control command. The keys must be sent consecutively, with no other data being written
to the Control( ) register between them. Note that to avoid conflict, the keys must be different from the
codes presented in the CNTL DATA column of Table 4-2 Control( ) subcommands.
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When in SEALED mode, the CONTROL_STATUS [SS] bit is set, but when the unseal keys are correctly
received by the bq27500/1, the [SS] bit is cleared. When the full-access keys are correctly received, then
the CONTROL_STATUS [FAS] bit is cleared.
Both the sets of keys for each level are 2 bytes each in length and are stored in data flash. The unseal
key (stored at Unseal Key 0 and Unseal Key 1) and the full-access key (stored at Full-Access Key 0
and Full-Access Key 1) can only be updated when in FULL-ACCESS mode. The order of the bytes
entered through the Control( ) command is the reverse of what is read from the part. For example, if the
first and second words of the Unseal Key 0 read returns 0x1234 and 0x5678, then the Control( ) should
supply 0x3412 and 0x7856 to unseal the part.
4.6 DATA FLASH SUMMARY
Table 4-7 summarizes the data flash locations available to the user, including their default, minimum, and
maximum values.
Table 4-7. Data Flash Summary
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
Name
Units
Configuration
Configuration
Configuration
Configuration
Configuration
Configuration
2
2
2
2
2
2
Safety
Safety
Safety
Safety
Safety
Safety
0
2
3
5
7
8
OT Chg
I2
U1
I2
0
0
0
0
0
0
1200
60
550
2
0.1°C
s
OT Chg Time
OT Chg Recovery
OT Dsg
1200
1200
60
500
600
2
0.1°C
0.1°C
s
I2
OT Dsg Time
OT Dsg Recovery
U1
I2
1200
550
0.1°C
Charge Inhibit
Config
Configuration
Configuration
Configuration
32
32
32
0
2
4
Charge Inhibit Temp Low
Charge Inhibit Temp High
Temp Hys
I2
I2
I2
–400
–400
0
1200
1200
100
0
0.1°C
0.1°C
0.1°C
Charge Inhibit
Config
450
50
Charge Inhibit
Config
Configuration
Configuration
Configuration
Configuration
34
34
34
34
Charge
Charge
Charge
Charge
2
4
6
8
Charging Voltage
I2
I2
I2
I2
0
20,000
500
4200
50
mV
Delta Temperature
0
0.1°C
0.1°C
0.1°C
Suspend Temperature Low
Suspend Temperature High
–400
–400
1200
1200
-50
550
Charge
Termination
Configuration
Configuration
Configuration
Configuration
36
36
36
36
2
4
6
8
Taper Current
I2
I2
0
0
0
0
1000
1000
1000
60
100
25
mA
mAh
mV
s
Charge
Termination
Minimum Taper Charge
Taper Voltage
Charge
Termination
I2
100
40
Charge
Termination
Current Taper Window
U1
Configuration
Configuration
Configuration
Configuration
48
48
48
48
Data
Data
Data
Data
4
5
Initial Standby Current
Initial Max Load Current
CC Threshold
I1
I2
I2
I2
–128
–32,767
100
0
–10
–500
900
mA
mA
0
7
32,767
65,535
mAh
mAh
10
Design Capacity
0
1000
bq27500
or
Configuration
48
Data
12
Device Name
S8
x
x
–
bq27501
Configuration
Configuration
Configuration
Configuration
49
49
49
49
Discharge
Discharge
Discharge
Discharge
0
1
2
3
SOC1 Set Threshold
SOC1 Clear Threshold
SOCF Set Threshold
SOCF Clear Threshold
U1
U1
U1
U1
0
0
0
0
255
255
255
255
150
175
75
mAh
mAh
mAh
mAh
100
Manufacturer
Info
System Data
57
0–31
Block A [0–31]
H1
0x00
0xff
0x00
–
18
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Table 4-7. Data Flash Summary (continued)
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
32–63
64–95
Name
Units
Manufacturer
Info
System Data
57
57
Block B [0–31]
H1
H1
0x00
0x00
0xff
0xff
0x00
0x00
–
–
Manufacturer
Info
System Data
Block C [0–31]
Configuration
Configuration
Configuration
Configuration
64
64
64
64
Registers
Registers
Registers
Registers
0
2
4
6
Operation Configuration
Pack 0 Voltage(1)
Pack 1 Voltage(1)
H2
U2
U2
U1
0x0000
0xffff
4200
4200
100
0x0979
1070
110
–
0
0
0
mV
mV
%
Pack V% Range(1)
50
Configuration
Configuration
Configuration
Configuration
68
68
68
68
Power
Power
Power
Power
0
7
Flash Update OK Voltage
Sleep Current
I2
I2
0
0
4200
100
2800
10
mV
mA
mA
mV
16
18
Hibernate Current
Hibernate Voltage
U2
U2
0
700
8
2400
3000
2550
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
80
80
80
80
80
80
80
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
IT Cfg
0
Load Select
U1
U1
I2
0
255
255
1
–
–
1
Load Mode
0
0
48
53
55
57
59
Terminate Voltage
User Rate-mA
–32,768
32,767
9000
3000
mV
I2
0
0
0
0
0
0
0
0
mA
User Rate-10mW
Reserve Cap-mAh
Reserve Cap-10mWh
I2
14,000
9000
10mW
mAh
10mWh
I2
I2
14,000
Current
Thresholds
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
81
81
81
81
81
81
0
2
4
6
8
9
Dsg Current Threshold
Chg Current Threshold
Quit Current
I2
I2
0
0
0
0
0
0
2000
2000
1000
8191
255
60
75
mA
mA
mA
s
Current
Thresholds
Current
Thresholds
I2
40
Current
Thresholds
Dsg Relax Time
U2
U1
U1
1800
60
Current
Thresholds
Chg Relax Time
Quit Relax Time
s
Current
Thresholds
63
1
s
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
Fuel Gauging
82
82
82
82
82
82
82
82
82
82
State
State
State
State
State
State
State
State
State
State
0
1
IT Enable
H1
H1
I2
0x00
0x00
0
0xff
0x00
0x00
1000
0
–
–
Application Status
Qmax 0
0xff
2
32,767
65,535
0x03
mAh
–
4
Cycle Count 0
Update Status 0
Qmax 1
U2
H1
I2
0
6
0x00
0
0x00
1000
0
–
7
32767
65,535
0x03
mAh
–
9
Cycle Count 1
Update Status 1
Avg I Last Run
Avg P Last Run
U2
H1
I2
0
11
16
18
0x00
–32,768
–32,768
0x00
–299
–1131
–
32,767
32,767
mA
mAh
I2
Default Ra
Tables
87
88
Def0 Ra
Def1 Ra
0–18
0–18
See Note(2)
Default Ra
Tables
Ra Tables
Ra Tables
Ra Tables
Ra Tables
91
92
93
94
Pack0 Ra
Pack1 Ra
Pack0 Rax
Pack1 Rax
0–18
0–18
0–18
0–18
See Note(2)
(1) bq27501 only.
(2) Encoded battery profile information created by bqEASY software.
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Table 4-7. Data Flash Summary (continued)
Subclass
ID
Data
Type
Min
Value
Max
Value
Default
Value
Class
Subclass
Offset
Name
Units
Calibration
Calibration
Calibration
Calibration
Calibration
Calibration
Calibration
104
104
104
104
104
104
104
Data
Data
Data
Data
Data
Data
Data
0
CC Gain
F4
F4
I2
0.1
29,826
–32,768
–128
4
1,193,046
32,767
127
0.47095
–
4
CC Delta
559,538.8
–
8
CC Offset
Board Offset
–1667
mV
10
11
12
13
I1
0
0
0
0
mV
Int Temp Offset
Ext Temp Offset
Pack V Offset
I1
–128
127
0.1°C
0.1°C
0.1°C
I1
–128
127
I1
–128
127
Calibration
107
Current
1
Deadband
U1
0
255
5
mA
Security
Security
Security
Security
112
112
112
112
Codes
Codes
Codes
Codes
0
2
4
6
Unseal Key 0
H2
H2
H2
H2
0x0000
0x0000
0x0000
0x0000
0xffff
0xffff
0xffff
0xffff
0x3672
0x0414
0xffff
–
–
–
–
Unseal Key 1
Full-Access Key 0
Full-Access Key 1
0xffff
5 FUNCTIONAL DESCRIPTION
5.1 FUEL GAUGING
The bq27500/1 measures the cell voltage, temperature, and current to determine battery SOC. The
bq27500/1 monitors charge and discharge activity by sensing the voltage across a small-value resistor (5
mΩ to 20 mΩ typ.) between the SRP and SRN pins and in series with the cell. By integrating charge
passing through a battery, the battery’s SOC is adjusted during battery charge or discharge.
The total battery capacity is found by comparing states of charge before and after applying the load with
the amount of charge passed. When an application load is applied, the impedance of the cell is measured
by comparing the OCV obtained from a predefined function for present SOC with the measured voltage
under load. Measurements of OCV and charge integration determine chemical state of charge and
chemical capacity (Qmax). The initial Qmax values are taken from a cell manufacturers' data sheet
multiplied by the number of parallel cells. It is also used for the value in Design Capacity. The bq27500/1
acquires and updates the battery-impedance profile during normal battery usage. It uses this profile, along
with SOC and the Qmax value, to determine FullChargeCapacity( ) and StateOfCharge( ), specifically for
the present load and temperature. FullChargeCapacity( ) is reported as capacity available from a fully
charged battery under the present load and temperature until Voltage( ) reaches the Term Voltage.
NominalAvailableCapacity( ) and FullAvailableCapacity( ) are the uncompensated (no- or light- load)
versions of RemainingCapacity( ) and FullChargeCapacity( ) respectively.
The bq27500/1 has two flags accessed by the Flags( ) function that warn when a battery's SOC has fallen
to critical levels. When RemainingCapacity( ) falls below the first capacity threshold, specified in SOC1
Set Threshold, the [SOC1] (State of Charge Initial) flag is set. The flag is cleared once
RemainingCapacity( ) rises above SOC1 Clear Threshold. The bq27500/1's BAT_LOW pin automatically
reflects the status of the [SOC1] flag. All units are in mAh.
When RemainingCapacity( ) falls below the second capacity threshold, SOCF Set Threshold, the [SOCF]
(State of Charge Final) flag is set, serving as a final discharge warning. Set SOCF Set Threshold = 0 to
deactivate the feature. Similarly, when RemainingCapacity( ) rises above SOCF Clear Threshold and the
[SOCF] flag has already been set, the [SOCF] flag is cleared. All units are in mAh.
5.2 IMPEDANCE TRACK™ VARIABLES
The bq27500/1 has several data flash variables that permit the user to customize the Impedance Track™
algorithm for optimized performance. These variables are dependent upon the power characteristics of the
application as well as the cell itself.
20
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5.2.1 Load Mode
Load Mode is used to select either the constant-current or constant-power model for the Impedance
Track™ algorithm as used in Load Select (see Load Select). When Load Mode is 0, the Constant
Current model is used (default). When 1, the Constant Power model is used. The [LDMD] bit of
CONTROL_STATUS reflects the status of Load Mode.
5.2.2 Load Select
Load Select defines the type of power or current model to be used to compute load-compensated
capacity in the Impedance Track™ algorithm. If Load Mode = 0 (Constant-Current) then the options
presented in Table 5-1 are available.
Table 5-1. Constant-Current Model Used When Load Mode = 0
LoadSelect Value
Current Model Used
Average discharge current from previous cycle: There is an internal register that records the average discharge
current through each entire discharge cycle. The previous average is stored in this register.
0
Present average discharge current: This is the average discharge current from the beginning of this discharge cycle
until present time.
1(default)
2
3
4
5
6
Average current: based on AverageCurrent( )
Current: based off of a low-pass-filtered version of AverageCurrent( ) (τ =14 s)
Design capacity / 5: C Rate based off of Design Capacity /5 or a C/5 rate in mA.
AtRate (mA): Use whatever current is in AtRate( )
User_Rate-mA: Use the value in User_Rate-mA. This mode provides a completely user-configurable method.
If Load Mode = 1 (Constant Power) then the following options shown in Table 5-2 are available.
Table 5-2. Constant-Power Model Used When Load Mode = 1
LoadSelect Value
Power Model Used
Average discharge power from previous cycle: There is an internal register that records the average discharge power
through each entire discharge cycle. The previous average is stored in this register.
0
Present average discharge power: This is the average discharge power from the beginning of this discharge cycle
until present time.
1(default)
2
3
4
5
6
Average current × voltage: based off the AverageCurrent( ) and Voltage( ).
Current × voltage: based off of a low-pass-filtered version of AverageCurrent( ) (τ=14 s) and Voltage( )
Design energy / 5: C Rate based off of Design Energy /5 or a C/5 rate in mA.
AtRate (10 mW): Use whatever value is in AtRate( ).
User_Rate-10mW: Use the value in User_Rate-10mW. This mode provides a completely user-configurable method.
5.2.3 Reserve Cap-mAh
Reserve Cap-mAh determines how much actual remaining capacity exists after reaching
0
RemainingCapacity( ), before Terminate Voltage is reached. A no-load rate of compensation is applied
to this reserve.
5.2.4 Reserve Cap-mWh
Reserve Cap-mWh determines how much actual remaining capacity exists after reaching
0
AvailableEnergy( ), before Terminate Voltage is reached. A no-load rate of compensation is applied to
this reserve capacity.
5.2.5 Dsg Current Threshold
This register is used as a threshold by many functions in the bq27500/1 to determine if actual discharge
current is flowing into or out of the cell. The default for this register is 100 mA, which should be sufficient
for most applications. This threshold should be set low enough to be below any normal application load
current but high enough to prevent noise or drift from affecting the measurement.
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5.2.6 Chg Current Threshold
This register is used as a threshold by many functions in the bq27500/1 to determine if actual charge
current is flowing into or out of the cell. The default for this register is 50 mA, which should be sufficient for
most applications. This threshold should be set low enough to be below any normal charge current but
high enough to prevent noise or drift from affecting the measurement.
5.2.7 Quit Current, DSG Relax Time, CHG Relax Time, and Quit Relax Time
The Quit Current is used as part of the Impedance Track™ algorithm to determine when the bq27500/1
enters relaxation mode from a current-flowing mode in either the charge direction or the discharge
direction. The value of Quit Current is set to a default value of 10 mA and should be above the standby
current of the system.
Either of the following criteria must be met to enter relaxation mode:
•
•
| AverageCurrent( ) | < | Quit Current | for Dsg Relax Time
| AverageCurrent( ) | < | Quit Current | for Chg Relax Time
After about 30 minutes in relaxation mode, the bq27500/1 attempts to take accurate OCV readings. An
additional requirement of dV/dt < 4 µV/s is required for the bq27500/1 to perform Qmax updates. These
updates are used in the Impedance Track™ algorithms. It is critical that the battery voltage be relaxed
during OCV readings to and that the current is not be higher than C/20 when attempting to go into
relaxation mode.
Quit Relax Time specifies the minimum time required for AverageCurrent( ) to remain above the
QuitCurrent threshold before exiting relaxation mode.
5.2.8 Qmax 0 and Qmax 1
Generically called Qmax, these dynamic variables contain the respective maximum chemical capacity of
the active cell profiles, and are determined by comparing states of charge before and after applying the
load with the amount of charge passed. They also correspond to capacity at a very low rate of discharge,
such as the C/20 rate. For high accuracy, this value is periodically updated by the bq27500/1 during
operation. Based on the battery cell capacity information, the initial value of chemical capacity should be
entered in the Qmax n field for each default cell profile. The Impedance Track™ algorithm updates these
values and maintains them the associated actual cell profiles.
5.2.9 Update Status 0 and Update Status 1
Bit 0 (0x01) of the Update Status n registers indicates that the bq27500/1 has learned new Qmax
parameters and is accurate. The remaining bits are reserved. Bits 0 is user-configurable; however, it is
also a status flag that can be set by the bq27500/1. Bit 0 should not be modified except when creating a
golden image file as explained in the application note Preparing Optimized Default Flash Constants for
specific Battery Types (SLUA334). Bit 0 is updated as needed by the bq27500/1.
5.2.10 Avg I Last Run
The bq27500 logs the current averaged from the beginning to the end of each discharge cycle. It stores
this average current from the previous discharge cycle in this register. This register should not be
modified. It is only updated by the bq27500/1 when required.
5.2.11 Avg P Last Run
The bq27500/1 logs the power averaged from the beginning to the end of each discharge cycle. It stores
this average power from the previous discharge cycle in this register. To get a correct average power
reading the bq27500/1 continuously multiplies instantaneous current times Voltage( ) to get power. It then
logs this data to derive the average power. This register should not be modified. It is only updated by the
bq27500/1 when required.
22
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5.2.12 Delta Voltage
The bq27500/1 stores the maximum difference of Voltage( ) during short load spikes and normal load, so
the Impedance Track™ algorithm can calculate remaining capacity for pulsed loads. It is not
recommended to change this value.
5.2.13 Default Ra and Ra Tables
These tables contain encoded data and, with the exception of the Default Ra Tables, are automatically
updated during device operation. No user changes should be made except for reading/writing the values
from a pre-learned pack (part of the process for creating golden image files).
5.3 DETAILED DESCRIPTION OF DEDICATED PINS
5.3.1 The Operation Configuration Register
Some bq27500/1 pins are configured via the Operation Configuration data flash register, as indicated in
Table 5-3. This register is programmed/read via the methods described in Section 4.2.1, Accessing the
Data Flash. The register is located at subclass = 64, offset = 0.
Table 5-3. Operation Configuration Bit Definition
Operation
Cfg
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
High byte
Low byte
RESCAP
–
–
–
PFC_CFG1
RMFCC
PFC_CFG0
BATL_POL
IWAKE
RSNS1
–
RSNS0
TEMPS
IDSELEN
SLEEP
BATG_POL
RESCAP = No-load rate of compensation is applied to the reserve capacity calculation. True when set. Default is 0.
PFC_CFG1/PFC_CFG0 = Pin function code (PFC) mode selection: PFC 0, 1, or 2 selected by 0/0, 0/1, or 1/0, respectively.
Default is PFC 1 (0/1).
IWAKE/RSNS1/RSNS0 = These bits configure the current wake function (see Table 5-4). Default is 0/0/1.
IDSELEN = Enables cell profile selection feature. True when set. Default is 1.
SLEEP = The fuel gauge can enter sleep, if operating conditions allow. True when set. Default is 1.
RMFCC = RM is updated with the value from FCC, on valid charge termination. True when set. Default is 1.
BATL_POL = BAT_LOW pin is active-high. True when set. Default is 1.
BATG_POL = BAT_GD pin is active-low. True when cleared. Default is 0.
TEMPS = Selects external thermistor for Temperature( ) measurements. True when set. Default is 1.
5.3.2 Pin Function Code Descriptions
The bq27500/1 has three possible pin-function variations that can be selected in accordance with the
circuit architecture of the end application. Each variation has been assigned a pin function code, or PFC.
When the PFC is set to 0, only the bq27500/1 measures battery temperature under discharge and
relaxation conditions. The charger does not receive any information from the bq27500/1 about the
temperature readings, and therefore operates open-loop with respect to battery temperature.
A PFC of 1 is like a PFC of 0, except temperature is also monitored during battery charging. If charging
temperature falls outside of the preset range defined in data flash, a charger can be disabled via the
BAT_GD pin until cell temperature recovers. See Section 5.6.2, Charge Inhibit, for additional details.
Finally when the PFC is set to 2, the battery thermistor can be shared between the fuel gauge and the
charger. The charger has full usage of the thermistor during battery charging. The fuel gauge uses the
thermistor exclusively during discharge and battery relaxation.
The PFC is specified in Operation Configuration [PFC_CFG1, PFC_CFG0]. The default is PFC = 1.
5.3.3 BAT_LOW Pin
The BAT_LOW pin provides a system processor with an electrical indicator of battery status. The signaling
on the BAT_LOW pin follows the status of the [SOC1] bit in the Flags( ) register. Note that the polarity of
the BAT_LOW pin can be inverted via the [BATL_POL] bit of Operation Configuration.
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5.3.4 Power Path Control With the BAT_GD Pin
The bq27500/1 must operate in conjunction with other electronics in a system appliance, such as chargers
and other ICs and subcircuits that draw appreciable power. After a battery is inserted into the system, this
electronics must be disabled, so that an accurate OCV can be read. The OCV is used for helping
determine which battery profile to use, as it constitutes part of the battery impedance measurement.
When a battery is inserted into a system, the Impedance Track™ algorithm requires that no charging of
the battery takes place and that any discharge is limited to less than C/20—these conditions are sufficient
for the fuel gauge to take an accurate OCV reading. To disable these functions, the BAT_GD pin is merely
set high (floating output pulled high). Once an OCV reading has be made, the BAT_GD pin is pulled low,
thereby enabling battery charging and regular discharge of the battery. The Operation Configuration
[BATG_POL] bit can be used to set the polarity of the battery good signal, should the default configuration
need to be changed.
The flowchart of Figure 5-1 details how the BAT_GD pin functions in the context of battery insertion and
removal, as well as NORMAL vs SLEEP modes.
In PFC 1, the BAT_GD pin is also used to disable battery charging when the bq27500/1 reads battery
temperatures outside the range defined by [Charge Inhibit Temp Low, Charge Inhibit Temp High]. The
BAT_GD line is returned to low once temperature falls within the range [Charge Inhibit Temp Low +
Temp Hys, Charge Inhibit Temp High – Temp Hys].
5.3.5 Battery Detection Using the BI/TOUT Pin
During power-up or hibernate activities, or any other activity where the bq27500/1 must determine whether
a battery is connected or not, the fuel gauge applies a test for battery presence. First, the BI/TOUT pin is
put into high-Z status. The weak 1.8-MΩ pullup resistor keeps the pin high while no battery is present.
When a battery is inserted (or is already inserted) into the system device, the BI/TOUT pin is pulled low.
This state is detected by the fuel gauge, which polls this pin every second when the gauge has power. A
battery disconnected status is assumed when the bq27500/1 reads a thermistor voltage that is near 2.5 V.
24
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Start
bq27500 POR
No
Batt
detected?
Yes
Init
(BAT_GD
disabled, OCV
taken, BAT_GD
enabled.)
No
Battery volt
sufficient
to FG?
Yes
NORMAL
SLEEP
Batt present
IT Operations
(dsg, chg, rlx)
ICC
>
Yes
Istandby -OR-
Tr > 30min?
Yes
No
Bad batt
detected?
No
Batt
removed?
No
Yes
Yes
Batt
removed?
No batt present
-OR- bad batt
(BAT_GD
No
disabled)
Forced
SLEEP
mode?
Yes
No
Yes
Batt
detected?
Bad batt
detected?
No
Yes
No
Yes
AC or USB
present?
No
End
Figure 5-1. BAT_GD Pin Operation, Based Upon Battery Presence and bq27500 Operating Mode
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5.4 TEMPERATURE MEASUREMENT
The bq27500/1 measures battery temperature via its TS input, in order to supply battery temperature
status information to the fuel gauging algorithm and charger-control sections of the gauge. Alternatively, it
can also measure internal temperature via its on-chip temperature sensor, but only if the [TEMPS] bit of
the Operation Configuration register is cleared.
Regardless of which sensor is used for measurement, a system processor can request the current battery
temperature by calling the Temperature( ) function (see Section 4.1.1, Standard Data Commands, for
specific information).
The recommended thermistor circuit uses an external 103AT-type thermistor. Additional circuit information
for connecting this thermistor to the bq27500/1 is shown in Section 8, Reference Schematic.
5.5 OVERTEMPERATURE INDICATION
5.5.1 Overtemperature: Charge
If during charging, Temperature( ) reaches the threshold of OT Chg for a period of OT Chg Time and
AverageCurrent( ) > Chg Current Threshold, then the [OTC] bit of Flags( ) is set.
If OT Chg Time = 0, then the feature is completely disabled. When Temperature( ) falls to OT Chg
Recovery, the [OTC] of Flags( ) is reset.
5.5.2 Overtemperature: Discharge
If during discharging, Temperature( ) reaches the threshold of OT Dsg for a period of OT Dsg Time, and
AverageCurrent( ) ≤ –Dsg Current Threshold, then the [OTD] bit of Flags( ) is set.
If OT Dsg Time = 0, then feature is completely disabled. When Temperature( ) falls to OT Dsg Recovery,
the [OTD] bit of Flags( ) is reset.
5.6 CHARGING AND CHARGE-TERMINATION INDICATION
5.6.1 Detecting Charge Termination
For proper bq27500/1 operation, the cell charging voltage must be specified by the user. The default value
for this variable is Charging Voltage = 4200 mV.
The bq27500/1 detects charge termination when (1) during 2 consecutive periods of Current Taper
Window, the AverageCurrent( ) is < Taper Current, (2) during the same periods, the accumulated
change in capacity > 0.25 mAh /Current Taper Window, and (3) Voltage( ) > Charging Voltage – Taper
Voltage. When this occurs, the [CHG] bit of Flags( ) is cleared. Also, if the [RMFCC] bit of Operation
Configuration is set, then RemainingCapacity( ) is set equal to FullChargeCapacity( ).
5.6.2 Charge Inhibit
When PFC = 1, the bq27500/1 can indicate when battery temperature has fallen below or risen above
predefined thresholds (Charge Inhibit Temp Low and Charge Inhibit Temp High, respectively). In this
mode, the BAT_GD line is made high to indicate this condition then returned to its low state, once battery
temperature returns to the range [Charge Inhibit Temp Low + Temp Hys, Charge Inhibit Temp High –
Temp Hys].
When PFC = 0 or 2, the bq27500/1 must be queried by the system in order to determine the battery
temperature. At that time, the bq27500/1 samples the temperature. This saves battery energy when
operating from battery, as periodic temperature updates are avoided during charging mode.
26
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5.7 POWER MODES
The bq27500/1 has four power modes: NORMAL, SLEEP, HIBERNATE, and BAT INSERT CHECK. In
NORMAL mode, the bq27500/1 is fully powered and can execute any allowable task. In SLEEP mode, the
fuel gauge exists in a reduced-power state, periodically taking measurements and performing calculations.
In HIBERNATE mode, the fuel gauge is in its lowest power state, but can be woken up by communication
activity or certain I/O activity. Finally, the BAT INSERT CHECK mode is a powered-up, but low-power
halted state, where the bq27500/1 resides when no battery is inserted into the system.
The relationship between these modes is shown in Figure 5-2.
5.7.1 NORMAL MODE
The fuel gauge is in NORMAL mode when not in any other power mode. During this mode,
AverageCurrent( ), Voltage( ) and Temperature( ) measurements are taken, and the interface data set is
updated. Decisions to change states are also made. This mode is exited by activating a different power
mode.
Because the gauge consumes the most power in NORMAL mode, the Impedance Track™ algorithm
minimizes the time the fuel gauge remains in this mode.
5.7.2 SLEEP MODE
SLEEP mode is entered automatically if the feature is enabled (Operation Configuration [SLEEP] = 1)
and AverageCurrent( ) is below the programmable level Sleep Current. Once entry into SLEEP mode has
been qualified, but prior to entering it, the bq27500/1 performs an ADC autocalibration to minimize offset.
During SLEEP mode, the bq27500/1 periodically takes data measurements and updates its data set.
However, a majority of its time is spent in an idle condition.
The bq27500/1 exits SLEEP if any entry condition is broken, specifically when (1) AverageCurrent( ) rises
above Sleep Current, or (2) a current in excess of IWAKE through RSENSE is detected.
In the event that a battery is removed from the system while a charger is present (and powering the
gauge), Impedance Track™ updates are not necessary. Hence, the fuel gauge enters a state that checks
for battery insertion and does not continue executing the Impedance Track™ algorithm.
While in SLEEP mode, the fuel gauge can suspend serial communications as much as 4ms by holding the
SDA pin low. This delay is necessary correctly process host communication, since the fuel gauge
processor is mostly halted while in SLEEP mode.
5.7.3 BAT-INSERT-CHECK MODE
This mode is a halted-CPU state that occurs when an adapter or other power source is present to power
the bq27500/1 (and system), yet no battery has been detected. When battery insertion is detected, a
series of initialization activities begins, which includes: OCV measurement, setting the BAT_GD pin, and
selecting the appropriate battery profiles.
Some commands issued by a system processor can be processed while the bq27500/1 is halted in this
mode. The gauge wakes up to process the command, then returns to the halted state awaiting battery
insertion.
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System-Side Impedance Track™ Fuel Gauge
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POR
Exit From HIBERNATE
Battery Removed
Exit From HIBERNATE
Communication Activity
AND Comm address is for
bq27500/1
BAT INSERT CHECK
Check for battery insertion
from HALT state.
No gauging
bq27500/1 clears Control Status
[HIBERNATE] = 0
Flags [BAT_DET] = 0
Recommend Host also set Control
Status [HIBERNATE] = 0
Entry to NORMAL
Flags [BAT_DET] = 1
Exit From NORMAL
Flags [BAT_DET] = 0
NORMAL
Fuel gauging and data
updated every1s
HIBERNATE
Wakeup From HIBERNATE
Communication Activity
AND
Comm address is NOT for
Exit From SLEEP
Flags [BAT_DET] = 0
Disable all bq27500/1
bq27500/1
subcircuits except GPIO
.
Negate BAT_GD
Entry to SLEEP
Operation Configuration [SLEEP] = 1
AND
| AverageCurrent( )| ≤ Sleep Current
Exit From SLEEP
| AverageCurrent( )| > Sleep Current
OR
Current is Detected above IWAKE
Exit From WAIT_HIBERNATE
Cell relaxed
WAIT_HIBERNATE
AND
| AverageCurrent() | < Hibernate
Exit From WAIT_HIBERNATE
OR
SLEEP
Host must set Control Status
[HIBERNATE] = 0
AND
Cell relaxed
AND
Fuel gauging and data
updatedevery 20 seconds
BAT_GD unchanged
Fuel gauging and data
updated every 20 seconds
VCELL < Hibernate Voltage
VCELL > Hibernate Voltage
System Shutdown
Exit From SLEEP
(Host has set Control Status
[HIBERNATE] = 1
OR
VCELL < Hibernate Voltage
Figure 5-2. Power Mode Diagram
5.7.4 HIBERNATE MODE
HIBERNATE mode should be used when the system equipment needs to enter a low-power state, and
minimal gauge power consumption is required. This mode is ideal when a system equipment is set to its
own HIBERNATE, SHUTDOWN, or OFF modes.
Before the fuel gauge can enter the HIBERNATE mode, the system must set the [HIBERNATE] bit of the
CONTROL_STATUS register. The gauge waits to enter HIBERNATE mode until it has taken a valid OCV
measurement and the magnitude of the average cell current has fallen below Hibernate Current. The
gauge can also enter HIBERNATE mode if the cell voltage falls below Hibernate Voltage, and a valid
OCV measurement has been taken. The gauge remains in HIBERNATE mode until the system issues a
direct I2C command to the gauge or a POR occurs. I2C communication that is not directed to the gauge
does not wake the gauge.
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It is important that BAT_GD be set to disable status (no battery charging/discharging). This prevents a
charger application from inadvertently charging the battery before an OCV reading can be taken. It is the
system’s responsibility to wake the bq27500/1 after it has gone into HIBERNATE mode. After waking, the
gauge can proceed with the initialization of the battery information (OCV, profile selection, etc.)
5.8 POWER CONTROL
5.8.1 RESET FUNCTIONS
When the bq27500/1 detects software reset ([RESET] bit of Control( ) initiated), it determines the type of
reset and increments the corresponding counter. This information is accessible by issuing the command
Control( ) function with the RESET_DATA subcommand.
As shown in Figure 5-3, if a partial reset was detected, a RAM checksum is generated and compared
against the previously stored checksum. If the checksum values do not match, the RAM is reinitialized (a
Full Reset). The stored checksum is updated every time RAM is altered.
DEVICE RESET
Generate Active
RAM checksum
value
NO
Stored
checksum
Re-initialize all
RAM
Do the Checksum
Values Match?
YES
NORMAL
OPERATION
Active RAM
changed ?
NO
YES
Store
checksum
Generate New
checksum value
Figure 5-3. Partial Reset Flow Diagram
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5.8.2 WAKE-UP COMPARATOR
The wake up comparator is used to indicate a change in cell current while the bq27500/1 is in either
SLEEP or HIBERNATE mode. Operation Configuration uses bits [RSNS1–RSNS0] to set the sense
resistor selection. Operation Configuration also uses the [IWAKE] bit to select one of two possible
voltage threshold ranges for the given sense resistor selection. An internal interrupt is generated when the
threshold is reached in either the charge or discharge direction. Setting both [RSNS1] and [RSNS0] to 0
disables this feature.
Table 5-4. IWAKE Threshold Settings(1)
RSNS1
RSNS0
IWAKE
Vth(SRP–SRN)
Disabled
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Disabled
1.0 mV or –1.0 mV
2.2 mV or –2.2 mV
2.2 mV or –2.2 mV
4.6 mV or –4.6 mV
4.6 mV or –4.6 mV
9.8 mV or –9.8 mV
(1) The actual resistance value vs. the setting of the sense resistor is not important, just the actual voltage
threshold when calculating the configuration.
5.8.3 FLASH UPDATES
Data Flash can only be updated if Voltage( ) ≥ Flash Update OK Voltage. Flash programming current can
cause an increase in LDO dropout. The value of Flash Update OK Voltage should be selected such that
the bq27500/1 VCC voltage does not fall below its minimum of 2.4 V during Flash write operations.
5.9 AUTOCALIBRATION
The bq27500/1 provides an autocalibration feature that measures the voltage offset error across SRP and
SRN as operating conditions change. It subtracts the resulting offset error from normal sense resistor
voltage, VSR, for maximum measurement accuracy.
Autocalibration of the ADC begins on entry to SLEEP mode, except if Temperature( ) is ≤ 5°C or
Temperature( ) ≥ 45°C.
The fuel gauge also performs a single offset when (1) the condition of AverageCurrent( ) ≤ 100 mA and (2)
{voltage change since last offset calibration ≥ 256 mV} or {temperature change since last offset calibration
is greater than 8°C for ≥ 60 s}.
Capacity and current measurements continue at the last measured rate during the offset calibration when
these measurements cannot be performed. If the battery voltage drops more than 32 mV during the offset
calibration, the load current has likely increased considerably; hence, the offset calibration is aborted.
30
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6 APPLICATION-SPECIFIC INFORMATION
6.1 BATTERY PROFILE STORAGE AND SELECTION
6.1.1 Common Profile Aspects
When a battery pack is removed from host equipment that implements the bq27500/01, the fuel gauge
maintains some of the battery information in case the battery is re-inserted. This way, the Impedance
Track™ algorithm has a means of recovering battery-status information, thereby maintaining good
state-of-charge (SOC) estimates.
Two default battery profiles are available to store battery information. They are used to provide the
Impedance Track™ algorithm with the default information on two possible battery types expected to be
used with the end-equipment. These default profiles can be used to support batteries of different
chemistry, same chemistry but different capacities, or same chemistry but different models. Default
profiles are programmed by the end-equipment manufacturer. Note that in the case of bq27500, only one
of the default profiles can be selected, and this selection cannot be changed during end-equipment
operation.
In addition to the default profiles, the bq27500/01 maintains two abbreviated profiles. These tables hold
dynamic battery data, and keep track of the status for up to two of the most recent batteries used. In most
cases, the bq27500/01 can manage the information on two removable battery packs.
6.1.2 Activities Upon Pack Insertion
6.1.2.1 First OCV and Impedance Measurement
At power up, the BAT_GD pin is inactive, so that the host cannot obtain power from the battery (this
depends on the actual implementation). In this state, the battery is put in an open-circuit condition. Next,
the bq27500/1 measures its first open-circuit voltage (OCV) via the BAT pin. From the OCV(SOC) table,
the SOC of the inserted battery is found. Then the BAT_GD pin is made active, and the impedance of the
inserted battery is calculated from the measured voltage and the load current: Z(SOC) = [OCV(SOC) – V]
/ I. This impedance is compared with the impedance of the dynamic profiles, Packn, and the default
profiles, Defn, for the same SOC (the letter n depicts either a 0 or 1).
6.1.3 Reading Application Status
The Application Status data flash location contains cell profile status information, and can be read using
the ApplicationStatus( ) extended command (0x6a). The bit configuration of this function/location is shown
in Table 6-1.
Table 6-1. ApplicationStatus( ) Bit Definitions.
Application
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
Configuration
Byte
—
—
—
—
—
—
UNSUPBAT LU_ PROF
UNSUPBAT = Flag indicating inserted battery is not supported in the current cell profiles. bq27501 only. True when set. Default is 0.
LU_PROF = Last profile used by fuel gauge. Pack0 last used when cleared. Pack1 last used when set. Default is 0.
6.2 APPLICATION-SPECIFIC FLOW AND CONTROL
6.2.1 Simple Battery (bq27500 Only)
The bq27500 supports only one type of battery profile. This profile is stored in both the Def0 and Def1
profiles. When a battery pack is inserted for the first time, the default profile is copied into the Packn
profiles. Then the Impedance Track™ algorithm begins fuel gauging, regularly updating Packn as the
battery is used.
When an existing pack is removed from the bq27500 and a different (or same) pack is inserted, cell
impedance is measured immediately after battery detection (see Section 6.1.2.1, First OCV and
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Impedance Measurement). The bq27500 chooses the profile which is closest to the measured impedance,
starting with the Packn profiles. That is, if the measured impedance matches Pack0, then the Pack0
profile is used. If the measured impedance matches Pack1, then the Pack1 profile is used. If the
measured impedance does not match the impedance stored in either Pack0 or Pack1, the battery pack is
deemed new (none of the previously used packs). The Def0/Def1 profile is copied into either the Pack0 or
Pack1 profile, overwriting the oldest Packn profile used.
6.2.2 Battery With Resistor ID (bq27501 Only)
The bq27501 can manage the information of up to two battery packs. For a given pack connected to the
fuel gauge, the identity of the battery is determined by a combination of (1) reading the pack ID resistor,
(2) measuring the impedance of the currently connected pack, and (3) remembering which pack
characteristics were most recently used by the gauge.
A battery-pack ID resistor should connect to the RID pin of the fuel gauge. Either A-Ω or B-Ω resistor
values should be used to indicate the battery type. If a battery connection is detected, then bq27501
measures the voltage developed at RID. If the voltage is Pack 0 Voltage, then it is identified as battery
pack with A resistor and the bq27501 uses the Pack0 profile. If the voltage measured is Pack 1 Voltage,
then it is identified as battery pack with B resistor and the bq27501 uses Pack1 profile.
The measurement window around each threshold is specified by Pack V% Range, which indicates the
positive or negative deviation around each level. Choosing RID values of 500 Ω and 8 kΩ for A and B,
respectively, correspond to Pack 0 Voltage and Pack 1 Voltage threshold levels of 110 mV and 1070
mV, respectively.
If the bq27501 measures a voltage other than Pack 0 Voltage or Pack 1 Voltage, then it sets
Application Configuration [UNSUPBAT] to 1, alerting the host system that the inserted battery is not
supported. The fuel gauge also writes the measured voltage into Pack 2 Voltage for this unsupported
battery. The host system can use this information to download the default profile for this battery if one
exists. The host system should unseal the gauge, then download the new battery profile into the older
Defn profile. The last-used profile is indicated by the Application Configuration [LU_PROF] bit.
Overwriting the older default profile allows the bq27501 to retain information stored regarding the most
recently used battery. After the new default profile is downloaded, the bq27501 sets Application
Configuration [EN_SENC] to 0.
6.2.2.1 Profile Selection
When a battery pack is inserted to the host for the first time, both the Packn profiles are empty. The
bq27501 copies the Def0 profile into Pack0 profile if the voltage measured on the RID pin is Pack 0
Voltage. The Impedance Track™ algorithm then begins fuel gauging, updating the Pack0 profile as the
battery is used. Similarly, it copies the Def1 profile into Pack1 profile if the voltage measured on the RID
pin is Pack 1 Voltage, and the Impedance Track™ algorithm then begins fuel gauging, updating the
Pack1 profile as the battery is used.
Assuming the bq27501 has copied the Def0 profile into Pack0 for the first pack used in the system, if the
pack is replaced with a second pack having the same resistor ID as the first, cell impedance is measured
after pack detection as explained in Section 6.1.2.1, First OCV and Impedance Measurement. This
impedance is compared with the Pack0 and Def0 profiles. If it matches the Pack0 impedance, then the
Pack0 profile is used (this situation indicates the last pack used was re-inserted). If not, a new pack is
assumed, so the bq27501 copies the Def0 profile into the empty Pack1 profile, and Pack1 is made the
active profile. This feature helps support accurate fuel gauging for two batteries with the same resistor ID.
The logic behind this profile selection process is also applied to the case where the first pack inserted
causes the bq27501 to copy the Def1 profile into Pack1.
If both the cell profiles are no longer empty (indicating two different battery packs have been used in the
system) and a battery is inserted, the bq27501 chooses the correct Packn profile to re-write. This decision
is based on the resistor ID, the impedance of the inserted battery, and the fact that the last-used battery
profile should not be overwritten.
32
APPLICATION-SPECIFIC INFORMATION
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7 COMMUNICATIONS
7.1 I2C INTERFACE
The 27500/1 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 8-bit device address will therefore be 0xAA or 0xAB for write or
read, respectively.
Host generated
bq27500/1 generated
DATA [7:0]
S
ADDR[6:0]
0
CMD[7:0]
P
S
ADDR[6:0]
A
DATA [7:0]
(b) quick read
DATA [7:0]
N
(a) 1-byte write
S
ADDR[6:0]
0
CMD[7:0]
Sr
ADDR[6:0]
1
A
N
(c) 1- byte read
S
ADDR[6:0]
0
CMD[7:0]
Sr
ADDR[6:0]
1
A
DATA [7:0]
A
. . .
DATA [7:0]
A . . . A P
N
(d) incremental read
S
ADDR[6:0]
CMD[7:0]
DATA [7:0]
DATA [7:0]
(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, will increment whenever data is acknowledged by the
bq27500/1 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):
The I2C engine will release both SDA and SCL if the I2C bus is held low for t(BUSERR). If the bq27500/1 was
holding the lines, releasing them will free the master to drive the lines. If an external condition is holding
either of the lines low, the I2C engine will enter the low power sleep mode.
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8 REFERENCE SCHEMATICS
8.1 SCHEMATIC
34
REFERENCE SCHEMATICS
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PACKAGE OPTION ADDENDUM
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30-Jul-2008
PACKAGING INFORMATION
Orderable Device
BQ27500DRZR
Status (1)
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
Drawing
NRND
SON
DRZ
12
12
12
12
12
3000 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR
no Sb/Br)
BQ27500DRZR-V100
BQ27500DRZT
ACTIVE
NRND
SON
SON
SON
SON
DRZ
DRZ
DRZ
DRZ
3000 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR
no Sb/Br)
250 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR
no Sb/Br)
BQ27500DRZT-V100
BQ27501DRZR
ACTIVE
PREVIEW
250 Green (RoHS & CU NIPDAU Level-2-260C-1 YEAR
no Sb/Br)
3000
TBD
Call TI
Call TI
(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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
IMPORTANT NOTICE
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TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
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Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Applications
Audio
Automotive
Broadband
Digital Control
Medical
Amplifiers
Data Converters
DSP
Clocks and Timers
Interface
amplifier.ti.com
dataconverter.ti.com
dsp.ti.com
www.ti.com/clocks
interface.ti.com
logic.ti.com
www.ti.com/audio
www.ti.com/automotive
www.ti.com/broadband
www.ti.com/digitalcontrol
www.ti.com/medical
www.ti.com/military
Logic
Military
Power Mgmt
Microcontrollers
RFID
power.ti.com
microcontroller.ti.com
www.ti-rfid.com
Optical Networking
Security
Telephony
Video & Imaging
Wireless
www.ti.com/opticalnetwork
www.ti.com/security
www.ti.com/telephony
www.ti.com/video
RF/IF and ZigBee® Solutions www.ti.com/lprf
www.ti.com/wireless
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2008, Texas Instruments Incorporated
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