Texas Instruments bq27500 User Manual
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1 INTRODUCTION

1.1 FEATURES

Battery Fuel Gauge for 1-SeriesLi-IonApplications

Resides on System Main Board

Works with Embedded or Removable Battery Packs

Two Varieties

bq27500: Uses PACK+,PACK-,andT Battery Terminals

bq27501: Includes Battery Pack ID Resistor (RID) Terminal

Micro-ControllerPeripheral Provides:

Accurate Battery Fuel Gauging

Internal Temperature Sensor for System Temperature Reporting

Battery Low Interrupt Warning

Battery Insertion Indicator

Battery ID Detection

96 bytes of Non-VolatileScratch Pad FLASH

Battery Fuel Gauge Based on Patented Impedance Track™ Technology

Models the Battery Discharge Curve for Accurate Time-to-EmptyPredictions

Automatically Adjusts for Battery Aging, Battery Self Discharge, and Temperature/Rate Inefficiencies

Low Value Sense Resistor (10mΩ or Less)

I2C™ Interface for Connection to SystemMicro-ControllerPort

12-Pin2,5 mm× 4,0 mm SON Package

bq27500

bq27501 System-SideImpedance Track™ Fuel Gauge

SLUS785 –SEPTEMBER2007

1.2APPLICATIONS

Smartphones

PDAs

Digital Still and Video Cameras

Handheld Terminals

MP3 or Multimedia Players

1.3DESCRIPTION

The Texas Instruments bq27500/01 System-SideLi-IonBattery Fuel Gauge is amicro-controllerperipheral that provides fuel gauging for single cellLi-Ionbattery packs. The device requires little systemmicro-controllerfirmware development. The bq27500/01 resides on the system’s main board, and manages an embedded battery(non-removable)or a removable battery pack.

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-timeto empty (min.), battery voltage (mV), and temperature (°C).

Battery fuel gauging with the bq27500 requires only PACK+ (P+), PACK- (P-),and Thermistor (T) connections to a removable battery pack or embedded battery circuit. The bq27501 works with identification resistors in battery packs, to gauge batteries of different fundamental chemistries and/or significantly different rated capacities.

 

TYPICAL APPLICATION

 

 

 

 

Host System

 

 

 

 

 

LDO

 

 

 

 

 

 

 

 

Single Cell Li-Ion

 

 

 

 

Battery Pack

 

 

Voltage

PACK+

 

 

 

 

Sense

 

 

 

 

 

 

 

 

Battery

RID

 

 

PROTECTION

 

Low

RID

 

IC

 

Sense*

 

 

Warning

 

 

 

 

 

 

 

 

 

 

 

Power

I2C

Temp

 

 

 

Management

Sense

T

 

 

 

 

 

 

Controller

 

 

 

 

bq 27500/1

 

 

 

 

 

 

 

 

Battery

 

PACK-

FETs

CHG

 

Good

 

DSG

 

 

 

 

 

 

 

 

 

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.

UNLESS OTHERWISE NOTED this

document

contains

Copyright © 2007, Texas Instruments Incorporated

PRODUCTION DATA information current as of publication date.

 

Products conform to specifications per

the terms

of Texas

 

Instruments standard warranty. Production processing does not

 

necessarily include testing of all parameters.

 

 

bq27500

bq27501

System-SideImpedance Track™ Fuel Gauge

www.ti.com

SLUS785 –SEPTEMBER2007

These devices have limited built-inESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.

Contents

1

INTRODUCTION ..........................................

1

 

4.2

DATA FLASH INTERFACE .........................

16

 

1.1

FEATURES ...........................................

1

 

4.3

MANUFACTURER INFORMATION BLOCKS ......

17

 

1.2

APPLICATIONS ......................................

1

 

4.4

ACCESS MODES ...................................

17

 

1.3

DESCRIPTION .......................................

1

 

4.5

SEALING/UNSEALING DATA FLASH ..............

17

2

DEVICE INFORMATION .................................

3

 

4.6

DATA FLASH SUMMARY...........................

18

 

2.1

AVAILABLE OPTIONS ...............................

3

5

FUNCTIONAL DESCRIPTION ........................

20

 

2.2

PIN DIAGRAMS ......................................

3

 

5.1

FUEL GAUGING ....................................

20

 

2.3

TERMINAL FUNCTIONS .............................

3

 

5.2

IMPEDANCE TRACK™ VARIABLES ...............

21

3

ELECTRICAL SPECIFICATIONS ......................

4

 

5.3

DETAILED DESCRIPTION OF DEDICATED PINS.

23

 

3.1

ABSOLUTE MAXIMUM RATINGS ...................

4

 

5.4

TEMPERATURE MEASUREMENT .................

26

 

3.2

RECOMMENDED OPERATING CONDITIONS......

4

 

5.5

OVERTEMPERATURE INDICATION ...............

26

 

3.3

POWER-ON RESET..................................

4

 

5.6

CHARGING AND CHARGE-TERMINATION

 

 

3.4

INTERNAL TEMPERATURE SENSOR

 

 

 

INDICATION.........................................

26

 

 

CHARACTERISTICS .................................

5

 

5.7

POWER MODES....................................

27

 

3.5

HIGH FREQUENCY OSCILLATOR ..................

5

 

5.8

POWER CONTROL .................................

29

 

3.6

LOW FREQUENCY OSCILLATOR...................

5

 

5.9

AUTOCALIBRATION................................

30

 

3.7

INTEGRATING ADC (COULOMB COUNTER)

 

6

APPLICATION-SPECIFICINFORMATION..........

31

 

 

CHARACTERISTICS .................................

5

 

6.1

BATTERY PROFILE STORAGE AND SELECTION

31

 

3.8

ADC (TEMPERATURE AND CELL

 

 

6.2

APPLICATION-SPECIFICFLOW AND CONTROL. 31

 

 

MEASUREMENT) CHARACTERISTICS

5

 

 

 

7

COMMUNICATIONS

33

 

3.9

DATA FLASH MEMORY CHARACTERISTICS

6

 

 

7.1

I2C INTERFACE

33

 

3.10

2

 

 

 

I C-COMPATIBLEINTERFACE COMMUNICATION

 

8

REFERENCE SCHEMATICS

34

 

 

TIMING CHARACTERISTICS ........................

6

4

GENERAL DESCRIPTION ..............................

8

 

8.1

SCHEMATIC ........................................

34

 

4.1

DATA COMMANDS ..................................

9

 

 

 

 

2

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