TEXAS INSTRUMENTS bq27541-V200 Technical data

BatteryPack

PACK-

PROTECTION

IC

PACK+

SDA

SCL

TS

bq27541-V200

LDO

REG25

REGIN

Vcc

SRP

SRN

SE

BAT

Vss

SHDQ

bq27541-V200

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Single Cell Li-Ion Battery Fuel Gauge for Battery Pack Integration

Check for Samples: bq27541-V200

1

FEATURES

23

• Battery Fuel Gauge for 1-Series Li-Ion
Applications

• Microcontroller Peripheral Provides:
– Accurate Battery Fuel Gauging
– Internal Temperature Sensor for System

Temperature Reporting
– SHA-1/HMAC Authentication
– Lifetime Data Logging
– 96 Bytes of Non-Volatile Scratch Pad

FLASH

• Battery Fuel Gauging Based on Patented
Impedance Track™ Technology

– Models Battery Discharge Curve for

Accurate Time-To-Empty Predictions

– Automatically Adjusts for Battery Aging,

Battery Self-Discharge, and
Temperature/Rate Inefficiencies

– Low-Value Sense Resistor (5mΩ to 20mΩ)

• HDQ and I2C™ Interface Formats for
Communication With Host System

• Small 12-pin 2,5 mm × 4 mm SON Package

SLUSA11 –FEBRUARY 2010

APPLICATIONS

• Smartphones

• PDAs

• Digital Still and Video Cameras

• Handheld Terminals

• MP3 or Multimedia Players

DESCRIPTION

The Texas Instruments bq27541 Li-Ion battery fuel
gauge is a microcontroller peripheral that provides
fuel gauging for single-cell Li-Ion battery packs. The
device requires little system microcontroller firmware
development for accurate battery fuel gauging. The
bq27541 resides within the battery pack or on the
system’s main-board with an embedded battery
(nonremovable).

The bq27541 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).

The bq27541 also features integrated support for
secure battery pack authentication, using the
SHA-1/HMAC authentication algorithm.

TYPICAL APPLICATION

1

2Impedance Track is a trademark of Texas Instruments.

2

3I

C is a trademark of Phillips Corporation.

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.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Copyright © 2010, Texas Instruments Incorporated

V

SS

SRN

SRP

V

CC

HDQ

SDA

SCL

1

2

3

4

5

6

12

11

10

9

8

7

TS

REGIN

BAT

SE

REG25

bq27541-V200

bq27541-V200

SLUSA11 –FEBRUARY 2010

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

DEVICE INFORMATION

AVAILABLE OPTIONS

PRODUCTION PACKAGE TA COMMUNICATION TAPE and REEL

bq27541DRZR-V200 3000
bq27541DRZT-V200 250

(1) bq27541-V200 is shipped in I2C mode

PART #

(1)

12-pin, 2,5-mm × 4-mm SON –40°C to 85°C I2C, HDQ

FORMAT QUANTITY

(1)

bq27541PIN DIAGRAMS

(TOP VIEW)

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PIN FUNCTIONS

PIN DESCRIPTION

NAME NO. TYPE

BAT 4 I Cell-voltage measurement input. ADC input. Decouple with 0.1mF capacitor.
REG25 2 P 2.5V output voltage of the internal integrated LDO. Connect a minimum 0.47mF ceramic capacitor.
REGIN 3 P The input voltage for the internal integrated LDO. Connect a 0.1mF ceramic capacitor.
SCL 11 I Slave I2C serial communications clock input line for communication with system (Slave). Use with 10kΩ

SDA 10 I/O Slave I2C serial communications data line for communication with system (Slave). Open-drain I/O. Use

SE 1 O Shutdown Enable output. Push-pull output.
HDQ 12 I/O HDQ serial communications line (Slave). Open-drain.
SRN 8 IA Analog input pin connected to the internal coulomb counter where SRN is nearest the PACK- connection.

SRP 7 IA Analog input pin connected to the internal coulomb counter where SRP is nearest the CELL- connection.

TS 9 IA Pack thermistor voltage sense (use 103AT-type thermistor). ADC input
Vcc 5 P Processor power input. The minimum 0.47mF capacitor connected to REG25 should be close to Vcc.
Vss 6 P Device ground

(1) I/O = Digital input/output, IA = Analog input, P = Power connection

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(1)

pull-up resistor (typical).

with 10kΩ pull-up resistor (typical).

Connect to 5-mΩ to 20-mΩ sense resistor.

Connect to 5-mΩ to 20-mΩ sense resistor

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SLUSA11 –FEBRUARY 2010

ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)

V

I

V

CC

V

IOD

V

BAT

V

I

ESD kV

T

F

T

stg

(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.

Regulator input, REGIN –0.3 to 24 V
Supply voltage range –0.3 to 2.75 V
Open-drain I/O pins (SDA, SCL, HDQ) –0.3 to 6 V
BAT input, (pin 4) –0.3 to 6 V
Input voltage range to all others (pins 1, 7, 8, 9) –0.3 to VCC+ 0.3 V
Human Body Model (HBM), BAT pin 1.5
Human Body Model (HBM), all pins 2
Functional temperature range –40 to 100 °C
Storage temperature range –65 to 150 °C

(1)

VALUE UNIT

DISSIPATION RATINGS

PACKAGE

12-pin DRZ

(1) 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) This data is based on using a 4-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.

(1)

TA≤ 40°C DERATING FACTOR R

qJA

POWER RATING TA≤ 40°C

(2)

482 mW 5.67 mW/°C 176°C/W

RECOMMENDED OPERATING CONDITIONS

TA= -40°C to 85°C; typical values at TA= 25°C and V

V

I

I

CC

I

(SLP)

I

(FULLSLP)

I

(HIB)

V

OL

V

OH(PP)

V

OH(OD)

V

IL

V

IH

V

(A1)

V

(A2)

V

(A3)

I

lkg

t

PUCD

(1) Specified by design. Not tested in production.

Supply voltage, REGIN V

Normal operating mode current

(1)

Low-power operating mode current

Low-power operating mode current

Hibernate operating mode current
Output voltage low (HDQ, SDA, SCL,

SE)
Output high voltage (SE) IOH = –1 mA VCC–0.5 V

Output high voltage (HDQ, SDA, SCL) VCC–0.5 V
Input voltage low (HDQ, SDA, SCL) –0.3 0.6 V

Input voltage high (HDQ, SDA, SCL) 1.2 6 V
Input voltage range (TS) VSS–0.125 2 V
Input voltage range (BAT) VSS–0.125 5 V
Input voltage range (SRP, SRN) VSS–0.125 0.125 V
Input leakage current (I/O pins) 0.3 mA
Power-up communication delay 250 ms

(REGIN)

No operating restrictions 2.7 5.5
No FLASH writes 2.45 2.7
Fuel gauge in NORMAL mode.

I

LOAD

Fuel gauge in SLEEP mode.

(1)

I

LOAD

Fuel gauge in FULLSLEEP mode.

(1)

I

LOAD

Fuel gauge in HIBERNATE mode.

(1)

I

LOAD

IOL= 3 mA 0.4 V

External pull-up resistor connected
to Vcc

= V

= 3.6 V (unless otherwise noted)

BAT

> Sleep Current

< Sleep Current

< Sleep Current

< Hibernate Current

MIN TYP MAX UNIT

131 mA

60 mA

21 mA

6 mA

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SLUSA11 –FEBRUARY 2010

POWER-ON RESET

TA= –40°C to 85°C, C
(unless otherwise noted)

V

IT+

V

HYS

Positive-going battery voltage input at V
Power-on reset hysteresis 45 115 185 mV

2.5 V LDO REGULATOR

TA= –40°C to 85°C, C
(unless otherwise noted)

PARAMETER TEST CONDITION MIN NOM MAX UNIT

V

O

V

DO

ΔV

(REGTEMP)

ΔV

(REGLINE)

ΔV

(REGLOAD)

(2)

I

OS

(1) LDO output current, I
(2) Specified by design. Not production tested.

Regulator output voltage,
REG25

Regulator dropout voltage TA= –40°C to 85°C mV

Regulator output change
with temperature

Line regulation 2.7 V ≤ V

Load regulation mV

Short circuit current limit V

= 0.47mF, 2.45 V < V

(REG)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(1)

= 0.47 mF, 2.45 V < V

(REG)

, is the sum of internal and external load currents.

OUT

(REGIN)

CC

(REGIN)

2.7 V ≤ V
I

≤ 16mA

OUT

2.45 V ≤ V
battery), I

2.7 V, I

OUT

2.45 V, I
V

(REGIN)

I

= 16 mA

OUT

0.2 mA ≤ I
3 mA ≤ I

(REG25)

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= V

< 5.5 V; typical values at TA= 25°C and V

BAT

(REGIN)

= V

BAT

= 3.6 V

2.05 2.20 2.31 V

= V

(REGIN)

(REGIN)

OUT

BAT

≤ 5.5 V,

< 2.7 V (low

≤ 3mA

< 5.5 V; typical values at TA= 25°C and V

2.42 2.48 2.57 V

TA= –40°C to 85°C

2.4 V

(REGIN)

= V

BAT

= 3.6 V

≤ 16 mA 280

≤ 3 mA 50

OUT

= 3.6 V,

(REGIN)

OUT

≤ 16 mA, V

OUT

≤ 5.5 V, I

≤ 3 mA, V

TA= –40°C to 85°C 0.3%

= 16 mA 11 25 mV

OUT

= 2.45 V 34 40

(REGIN)

= 2.7 V 31

(REGIN)

= 0 V TA= –40°C to 85°C 250 mA

INTERNAL TEMPERATURE SENSOR CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

G

(TEMP)

Temperature sensor voltage gain –2.0 mV/°C

= 0.47mF, 2.45 V < V

(REG)

(REGIN)

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

HIGH FREQUENCY OSCILLATOR

TA= –40°C to 85°C, C
(unless otherwise noted)

f

(OSC)

f

(EIO)

t

(SXO)

(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 startup time is defined as the time it takes for the oscillator output frequency to be ±3%.

Operating frequency 2.097 MHz

Frequency error

Start-up time

= 0.47mF, 2.45 V < V

(REG)

(REGIN)

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

TA= 0°C to 60°C –2.0% 0.38% 2.0%

(1) (2)

TA= –20°C to 70°C –3.0% 0.38% 3.0%
TA= –40°C to 85°C -4.5% 0.38% 4.5%

(3)

= V

= V

BAT

BAT

= 3.6 V

= 3.6 V

(REGIN)

(REGIN)

2.5 5 ms

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SLUSA11 –FEBRUARY 2010

LOW FREQUENCY OSCILLATOR

TA= –40°C to 85°C, C
(unless otherwise noted)

f

(LOSC)

f

(LEIO)

t

(LSXO)

(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 startup time is defined as the time it takes for the oscillator output frequency to be ±3% of typical oscillator frequency.

Operating frequency 32.768 KHz

Frequency error

Start-up time

= 0.47mF, 2.45 V < V

(REG)

(REGIN)

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

(REGIN)

= V

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

TA= 0°C to 60°C –1.5% 0.25% 1.5%

(1) (2)

TA= –20°C to 70°C –2.5% 0.25% 2.5%
TA= –40°C to 85°C -4.0% 0.25% 4.0%

(3)

INTEGRATING ADC (COULOMB COUNTER) CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

V

IN(SR)

t

CONV(SR)

V

OS(SR)

I

NL

Z

IN(SR)

I

lkg(SR)

(1) Specified by design. Not production tested.

Input voltage range, V
Conversion time Single conversion 1 s
Resolution 14 15 bits
Input offset 10 mV
Integral nonlinearity error ±0.007 ±0.034 FSR
Effective input resistance
Input leakage current

= 0.47mF, 2.45 V < V

(REG)

(REGIN)

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

(REGIN)

= V

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(SRN)

(1)

(1)

and V

(SRP)

VSR= V

(SRN)

– V

(SRP)

–0.125 0.125 V

2.5 MΩ

= 3.6 V

BAT

500 ms

= 3.6 V

BAT

0.3 mA

ADC (TEMPERATURE AND CELL VOLTAGE) CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V

IN(ADC)

t

CONV(ADC)

V

OS(ADC)

Z

(ADC1)

Z

(ADC2)

I

lkg(ADC)

(1) Specified by design. Not production tested.

Input voltage range –0.2 1 V
Conversion time 125 ms
Resolution 14 15 bits
Input offset 1 mV
Effective input resistance (TS)
Effective input resistance (BAT)

Input leakage current

= 0.47mF, 2.45 V < V

(REG)

(1)

= V

(REGIN)

(1)

(1)

bq27541 not measuring cell voltage 8 MΩ

< 5.5 V; typical values at TA= 25°C and V

BAT

bq27541 measuring cell voltage 100 kΩ

DATA FLASH MEMORY CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

t

DR

t

WORDPROG

I

CCPROG

(1) Specified by design. Not production tested.

Data retention
Flash programming write-cycles
Word programming time
Flash-write supply current

= 0.47mF, 2.45 V < V

(REG)

(REGIN)

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(1)

(1)

(1)

(1)

= V

(REGIN)

BAT

= 3.6 V

8 MΩ

0.3 mA

= V

(REGIN)

BAT

= 3.6 V

10 Years

20,000 Cycles

2 ms

5 10 mA

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t

(B)

t

(BR)

t

(HW1)

t

(HW0)

t

(CYCH)

t

(DW1)

t

(DW0)

t

(CYCD)

Break

7-bitaddress

8-bitdata

(a) BreakandBreakRecovery

(c) Host TransmittedBit

(d) Gauge TransmittedBit

(e) GaugetoHostResponse

1.2V

t

(RISE)

(b) HDQlinerisetime

1-bit
R/W

t

(RSPS)

bq27541-V200

SLUSA11 –FEBRUARY 2010

HDQ COMMUNICATION TIMING CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

t

(CYCH)

t

(CYCD)

t

(HW1)

t

(DW1)

t

(HW0)

t

(DW0)

t

(RSPS)

t

(B)

t

(BR)

t

(RISE)

= 0.47mF, 2.45 V < V

REG

REGIN

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Cycle time, host to bq27541 190 ms
Cycle time, bq27541 to host 190 205 250 ms
Host sends 1 to bq27541 0.5 50 ms
bq27541 sends 1 to host 32 50 ms
Host sends 0 to bq27541 86 145 ms
bq27541 sends 0 to host 80 145 ms
Response time, bq27541 to host 190 320 ms
Break time 190 ms
Break recovery time 40 ms
HDQ line resing time to logic 1 (1.2V) 950 ns

REGIN

= V

BAT

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= 3.6 V

Figure 1. Timing Diagrams

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t

SU(STA)

SCL

SDA

t

w(H)

t

w(L)

t

f

t

r

t

(BUF)

t

r

t

d(STA)

REPEATED

START

t

h(DAT)tsu(DAT)

t

f

t

su(STOP)

STOP START

bq27541-V200

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I2C-COMPATIBLE INTERFACE TIMING CHARACTERISTICS

TA= –40°C to 85°C, C
(unless otherwise noted)

t

r

t

f

t

w(H)

t

w(L)

t

su(STA)

t

d(STA)

t

su(DAT)

t

h(DAT)

t

su(STOP)

t

BUF

f

SCL

SCL/SDA rise time 300 ns
SCL/SDA fall time 300 ns
SCL pulse width (high) 600 ns
SCL pulse width (low) 1.3 ms
Setup for repeated start 600 ns
Start to first falling edge of SCL 600 ns
Data setup time 1000 ns
Data hold time 0 ns
Setup time for stop 600 ns
Bus free time between stop and start 66 ms
Clock frequency 400 kHz

= 0.47mF, 2.45 V < V

REG

REGIN

= V

< 5.5 V; typical values at TA= 25°C and V

BAT

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

SLUSA11 –FEBRUARY 2010

= V

REGIN

BAT

= 3.6 V

Figure 2. I2C-Compatible Interface Timing Diagrams

GENERAL DESCRIPTION

The bq27541 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 bq27541 control and status registers,
as well as its data flash locations. Commands are sent from system to gauge using the bq27541’s serial
communications engine, and can be executed during application development, pack manufacture, or
end-equipment operation.

Cell information is stored in the bq27541 in non-volatile flash memory. Many of these data flash locations are
accessible during application development. They cannot, generally, be accessed directly during end-equipment
operation. Access to these locations is achieved by either use of the bq27541’s 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 bq27541 provides 96 bytes of user-programmable data flash memory, partitioned into three (3) 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
Manufacturer Information Blocks. The key to the bq27541’s high-accuracy gas gauging prediction is Texas
Instrument’s 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.

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The bq27541 measures charge/discharge activity by monitoring the voltage across a small-value series sense
resistor (5 mΩ to 20 mΩ typ.) located between the CELL-and the battery’s PACK-terminal. When a cell is
attached to the bq27541, cell impedance is computed, based on cell current, cell open-circuit voltage (OCV), and
cell voltage under loading conditions.

The bq27541 external temperature sensing is optimized with the use of a high accuracy negative temperature
coefficient (NTC) thermistor with R25 = 10kΩ ± 1% and B25/85 = 3435kΩ ± 1% (such as Semitec 103AT for
measurement). The bq2741 can also be configured to use its internal temperature sensor. The bq27541 uses
temperature to monitor the battery-pack environment, which is used for fuel gauging and cell protection
functionality.

To minimize power consumption, the bq27541 has different power modes: NORMAL, SLEEP, FULLSLEEP,
HIBERNATE, and PRESHUTDOWN. The bq27541 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 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: italics with brackets[]. e.g. [TDA]
Data flash bits: italics, bold, and brackets[]. e.g: [LED1]
Modes and states: ALL CAPITALS. e.g. UNSEALED mode

do not delete this subsection

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DATA COMMANDS

STANDARD DATA COMMANDS

The bq27541 uses a series of 2-byte standard commands to enable system reading and writing of battery
information. Each standard command has an associated command-code pair, as indicated in Table 1. Each
protocol has specific means to access the data at each Command Code. DataRAM is updated and read by the
gauge only once per second. Standard commands are accessible in NORMAL operation mode.

Table 1. Standard Commands

NAME COMMAND CODE UNITS SEALED

Control( ) CNTL 0x00 / 0x01 N/A R/W
AtRate( ) AR 0x02 / 0x03 mA R/W
AtRateTimeToEmpty( ) ARTTE 0x04 / 0x05 Minutes R
Temperature( ) TEMP 0x06 / 0x07 0.1K R
Voltage( ) VOLT 0x08 / 0x09 mV R
Flags( ) FLAGS 0x0a / 0x0b N/A R
NominalAvailableCapacity( ) NAC 0x0c / 0x0d mAh R
FullAvailableCapacity( ) FAC 0x0e / 0x0f mAh R
RemainingCapacity( ) RM 0x10 / 0x11 mAh R
FullChargeCapacity( ) FCC 0x12 / 0x13 mAh R
AverageCurrent( ) AI 0x14 / 0x15 mA R
TimeToEmpty( ) TTE 0x16 / 0x17 Minutes R
TimeToFull( ) TTF 0x18 / 0x19 Minutes R
StandbyCurrent( ) SI 0x1a / 0x1b mA R
StandbyTimeToEmpty( ) STTE 0x1c / 0x1d Minutes R
MaxLoadCurrent( ) MLI 0x1e / 0x1f mA R
MaxLoadTimeToEmpty( ) MLTTE 0x20 / 0x21 Minutes R
AvailableEnergy( ) AE 0x22 / 0x23 10 mWhr R
AveragePower( ) AP 0x24 / 0x25 10 mW R
TTEatConstantPower( ) TTECP 0x26 / 0x27 Minutes R

Internal_Temp( ) INTTEMP 0x28 / 0x29 0.1°K R
CycleCount( ) CC 0x2a / 0x2b Counts R
StateOfCharge( ) SOC 0x2c / 0x2d % R
StateOfHealth( ) SOH 0x2e / 0x2f % / num R
PassedCharge( ) PCHG 0x34 / 0x35 mAh R
DOD0( ) DOD0 0x36 / 0x37 HEX# R

ACCESS

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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
bq27541 during normal operation and additional features when the bq27541 is in different access modes, as
described in Table 2.

Table 2. Control( ) Subcommands

CNTL FUNCTION CNTL DATA SEALED DESCRIPTION

CONTROL_STATUS 0x0000 Yes Reports the status of DF Checksum, Hibernate, IT, etc.
DEVICE_TYPE 0x0001 Yes Reports the device type of 0x0541 (indicating bq27541)
FW_VERSION 0x0002 Yes Reports the firmware version on the device type
HW_VERSION 0x0003 Yes Reports the hardware version of the device type
DF_CHECKSUM 0x0004 No Enables a data flash checksum to be generated and reports on a read
RESET_DATA 0x0005 No Returns reset data
Reserved 0x0006 No Not to be used
PREV_MACWRITE 0x0007 No Returns previous MAC command code
CHEM_ID 0x0008 Yes Reports the chemical identifier of the Impedance Track™ configuration
DF_VERSION 0x000C Yes Reports the data flash version on the device
SET_FULLSLEEP 0x0010 No Set the [FullSleep] bit in Control Status register to 1
SET_HIBERNATE 0x0011 Yes Forces CONTROL_STATUS [HIBERNATE] to 1
CLEAR_HIBERNATE 0x0012 Yes Forces CONTROL_STATUS [HIBERNATE] to 0
SET_SHUTDOWN 0x0013 Yes Enables the SE pin to change state
CLEAR_SHUTDOWN 0x0014 Yes Disables the SE pin from changing state
SET_HDQINTEN 0x0015 Yes Forces CONTROL_STATUS [HDQIntEn] to 1
CLEAR_HDQINTEN 0x0016 Yes Forces CONTROL_STATUS [HDQIntEn] to 0
SEALED 0x0020 No Places the bq27541 is SEALED access mode
IT_ENABLE 0x0021 No Enables the Impedance Track™ algorithm
CAL_MODE 0x0040 No Places the bq27541 in calibration mode
RESET 0x0041 No Forces a full reset of the bq27541

ACCESS

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CONTROL_STATUS: 0X0000

Instructs the fuel gauge to return status information to Control addresses 0x00/0x01. The status word includes
the following information.

Table 3. CONTROL_STATUS Flags

bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0

High Byte SE FAS SS CSV CCA BCA – HDAIntEn

Low Byte SHUTDOWN HIBERNATE FULLSLEEP SLEEP LDMD RUP_DIS VOK QEN

SE = Status bit indicating the SE pin is active. True when set. Default is 0.

FAS = Status bit indicating the bq27541 is in FULL ACCESS SEALED state. Active when set.

SS = Status bit indicating the bq27541 is in the 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 bq27541 Coulomb Counter Calibration routine is active. Active when set.

BCA = Status bit indicating the bq27541 Board Calibration routine is active. Active when set.

HDQIntEn = Status bit indicating the HDQ interrupt function is active. True when set. Default is 0.

SHUTDOWN = Control bit indicating the fuel gauge can force its SE pin low to signal an external shutdown. True when set. Default is 0.

HIBERNATE = Status bit indicating a request for entry into HIBERNATE from SLEEP mode has been issued. True when set. Default is

FULLSLEEP =

SLEEP = Status bit indicating the bq27541 is in SLEEP mode. True when set

LDMD = Status bit indicating the bq27541 Impedance Track™ algorithm using constant-power mode. True when set. Default is 0

RUP_DIS = Status bit indicating the bq27541 Ra table updates are disabled. True when set.

VOK = Status bit indicating cell voltages are OK for Qmax updates. True when set.
QEN = Status bit indicating the bq27541 Qmax updates are enabled. True when set.

0. Control bit when set will put the bq27541 into the lower power state of SLEEP mode. It is not possible to monitor this
bit

Status bit indicating the bq27541 is in FULLSLEEP mode. True when set. The state can be detected by monitoring the
power used by the bq27541 because any communication will automatically clear it

(constant-current mode).

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DEVICE_TYPE: 0X0001

Instructs the fuel gauge to return the device type to addresses 0x00/0x01.

FW_VERSION: 0X0002

Instructs the fuel gauge to return the firmware version to addresses 0x00/0x01.

HW_VERSION: 0X0003

Instructs the fuel gauge to return the hardware version to addresses 0x00/0x01.

DF_CHECKSUM: 0X0004

Instructs the fuel gauge to compute the checksum of the data flash memory. The checksum value is written and
returned to addresses 0x00/0x01 (UNSEALED mode only). The checksum will not be calculated in SEALED
mode; however, the checksum value can still be read.

RESET_DATA: 0X0005

Instructs the fuel gauge to return the reset data to addresses 0x00/0x01.

PREV_MACWRITE: 0X0007

Instructs the fuel gauge to return the previous command written to addresses 0x00/0x01. The value returned is
limited to less than 0x0020.

CHEM_ID: 0X0008

Instructs the fuel gauge to return the chemical identifier for the Impedance Track™ configuration to addresses
0x00/0x01.

DF_VERSION: 0x000C

Instructs the gas gauge to return the data flash version to addresses 0x00/0x01

SET_FULLSLEEP: 0X0010

Instructs the gas gauge to set the FullSleep bit in Control Status register to 1. This will allow the gauge to enter
the FULLSLEEP power mode after the transition to SLEEP power state is detected. In FullSleep mode less
power is consumed by disabling an oscillator circuit used by the communication engines. For HDQ
communication one host message will be dropped. For I2C communications the first I2C message will incur a
6–8 millisecond clock stretch while the oscillator is started and stabilized. A communication to the device in
FULLSLEEP will force the part back to the SLEEP mode.

SET_HIBERNATE: 0X0011

Instructs the fuel gauge to force the CONTROL_STATUS [HIBERNATE] bit to 1. This will allow 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.

CLEAR_HIBERNATE: 0X0012

Instructs the fuel gauge to force the CONTROL_STATUS [HIBERNATE] bit to 0. This will prevent the gauge from
entering the HIBERNATE power mode after the transition to SLEEP power state is detected. It can also be used
to force the gauge out of HIBERNATE mode.

SET_SHUTDOWN: 0x0013

Sets the CONTROL_STATUS [SHUTDOWN] bit to 1, thereby enabling the SE pin to change state. The
Impedance Track algorithm controls the setting of the SE pin, depending on whether the conditions are met for
fuel gauge shutdown or not.

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CLEAR_SHUTDOWN: 0X0014

Disables the SE pin from changing state. The SE pin is left in a high-impedance state.

SET_HDQINTEN: 0x0015

Instructs the fuel gauge to set the CONTROL_STATUS [HDQIntEn] bit to 1. This will enable the HDQ Interrupt
function. When the this subcommand is received, the bq27541 will detect any of the interrupt conditions and
assert the interrupt at one second intervals until the CLEAR_HDQINTEN command is received or the count of
HDQHostIntrTries has lapsed.

CLEAR_HDQINTEN: 0x0016

Instructs the fuel gauge to set the CONTROL_STATUS [HDQIntEn] bit to 0. This will disable the HDQ Interrupt
function.

SEALED: 0X0020

Instructs the gas gauge to transition from UNSEALED state to SEALED state. The gas gauge should always be
set to SEALED state for use in customer’s end equipment.

IT ENABLE: 0X0021

This command forces the fuel gauge to begin the Impedance Track™ algorithm, sets the active
UpdateStatuslocation 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.

CAL MODE: 0X0040

This command instructs the gas gauge to enter calibration mode. This command is only available when the gas
gauge is UNSEALED.

RESET: 0X0041

This command instructs the gas gauge to perform a full reset. This command is only available when the gas
gauge is UNSEALED.

AtRate( ): 0x02/0x03

The AtRate( ) read-/write-word function is the first half of a two-function command call-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 will force AtRateTimeToEmpty( ) to return 65,535. Both the AtRate( ) and
AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.

AtRateTimeToEmpty( ): 0x04/0x05

This read-only 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 1s. Both the AtRate( )
and AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.

Temperature( ): 0x06/0x07

This read-only function returns an unsigned integer value of the battery temperature in units of 0.1K measured by
the fuel gauge.

Voltage( ): 0x08/0x09

This read-only function returns an unsigned integer value of the measured cell-pack voltage in mV with a range
of 0 to 6000 mV.

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