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Texas Instruments System-Side Impedance Track bq27500 Instruction Manual

System-side impedance track fuel gauge
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1 INTRODUCTION

1.1 FEATURES

Battery Fuel Gauge for 1-Series Li-Ion

Applications

Resides on System Main Board
– Works with Embedded or Removable
Battery Packs
Two Varieties
– bq27500: Uses PACK+, PACK-, and T
Battery Terminals
– bq27501: Includes Battery Pack ID Resistor
(RID) Terminal
Micro-Controller Peripheral 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-Volatile Scratch Pad
FLASH
Battery Fuel Gauge Based on Patented
Impedance Track™ Technology
– Models the 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 (10m
2
I
C™ Interface for Connection to System
Micro-Controller Port
12-Pin 2,5 mm
4,0 mm SON Package
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.
2
I
C is a trademark of Philips Electronics.
UNLESS
OTHERWISE
NOTED
this
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.
or Less)
TYPICAL APPLICATION
Host System
Power
I2C
Management
Controller
document
contains
System-Side Impedance Track™ Fuel Gauge
1.2
APPLICATIONS
Smartphones
PDAs
Digital Still and Video Cameras
Handheld Terminals
MP3 or Multimedia Players
1.3

DESCRIPTION

The Texas Instruments bq27500/01 System-Side
Li-Ion Battery Fuel Gauge is a micro-controller
peripheral that provides fuel gauging for single cell
Li-Ion battery packs. The device requires little system
micro-controller
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-time to 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
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.
LDO
Voltage
PACK+
Sense
Battery
RID
Low
RID
Sense*
Warning
Temp
Sense
T
bq27500/1
Battery
PACK-
Good
Current
Sense
Copyright © 2007, Texas Instruments Incorporated
SLUS785 – SEPTEMBER 2007
firmware
development.
a
removable
battery
Single Cell Li-Ion
Battery Pack
PROTECTION
IC
CHG
FETs
DSG
* bq27501 Only
bq27500
bq27501
The
pack
or

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Summary of Contents for Texas Instruments System-Side Impedance Track bq27500

  • Page 1: Introduction

    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. C is a trademark of Philips Electronics.

  • Page 2: Table Of Contents

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Contents ..........

  • Page 3: Device Information

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 2 DEVICE INFORMATION 2.1 AVAILABLE OPTIONS COMMUNICATION TAPE and REEL PART NUMBER PACKAGE FORMAT QUANTITY bq27500DRZR 3000 bq27500DRZT 12-pin, 2,5 mm x 4,0 mm –40 C to 85 C bq27501DRZR 3000 bq27501DRZT...

  • Page 4: Electrical Specifications

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 3 ELECTRICAL SPECIFICATIONS 3.1 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) PARAMETER VALUE UNIT Supply voltage range –0.3 to 2.75 Open-drain I/O pins (BI_TOUT, SDA, SDL, BAT_GD) –0.3 to 6 BAT input pin –0.3 to +6...

  • Page 5: Internal Temperature Sensor Characteristics

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 INTERNAL TEMPERATURE SENSOR CHARACTERISTICS = –40 C to 85 C, 2.4 V < V < 2.6 V; Typical Values at T = 25 C and V = 2.5 V (unless otherwise noted) PARAMETER TEST CONDITIONS UNIT...

  • Page 6: I 2 C-Compatible Interface Communication Timing Characteristics

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS (continued) = –40 C to 85 C, 2.4 V < V < 2.6 V; Typical Values at T = 25 C and V = 2.5 V (unless otherwise noted) PARAMETER TEST CONDITIONS...
  • Page 7 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Figure 3-1. I C-Compatible Interface Timing Diagrams Submit Documentation Feedback ELECTRICAL SPECIFICATIONS...

  • Page 8: General Description

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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).

  • Page 9: Data Commands

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 10 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 4.1.1.1 Control( ): 0x00/0x01 Issuing a Control( ) command requires a subsequent two-byte sub-command. These additional bytes specify the particular control function desired. The Control( ) command allows the system to control specific features of the bq27500 during normal operation and additional features when the bq27500/1 is in different access modes, as described in Table...
  • Page 11 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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 RESET_DATA: 0x0005 Instructs the fuel gauge to return the reset data to addresses 0x00/0x01, with the low-byte being the number of partial resets and the high-byte the number of full resets.
  • Page 12 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 4.1.1.1.15 CAL MODE: 0x0040 This command instructs the fuel gauge to enter calibration mode. This command is only available when the fuel gauge is UNSEALED. 4.1.1.1.16 RESET: 0x0041 This command instructs the fuel gauge to perform a full reset.
  • Page 13 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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 bit. 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.
  • Page 14 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 15 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Table 4-5. Extended Data Commands (continued) COMMAND SEALED UNSEALED NAME UNITS (1) (2) (1) (2) CODE ACCESS ACCESS BlockData( ) 0x55 0x5f BlockDataCheckSum( ) DFDCKS 0x60 BlockDataControl( ) DFDCNTL 0x61 DeviceNameLength( )

  • Page 16: Data Flash Interface

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.

  • Page 17: Manufacturer Information Blocks

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 4.3 MANUFACTURER INFORMATION BLOCKS The bq27350 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.

  • Page 18: Data Flash Summary

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 19 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Table 4-7. Data Flash Summary (continued) Subclass Data Default Class Subclass Offset Name Units Type Value Value Value Configuration Registers Operation Configuration 0x0000 0xffff 0x0979 – Configuration Registers Pack 0 Voltage 4200 1000...

  • Page 20: Functional Description

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Table 4-7. Data Flash Summary (continued) Subclass Data Default Class Subclass Offset Name Units Type Value Value Value Ra Tables Pack0 Ra 0-18 Ra Tables Pack1 Ra 0-18 See Note Ra Tables Pack0 Rax...

  • Page 21: Impedance Track™ Variables

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 22 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Dsg Current Threshold This register is used as a threshold by many functions in the bq27350 to determine if actual discharge current is flowing into or out of the cell. The default for this register is 100mA 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.

  • Page 23: Detailed Description Of Dedicated Pins

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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 desribed in Section 4.2.1 Accessing the Data Flash.
  • Page 24 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 25 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 Start Bq27500 POR Batt detected ? Init (“BAT_GD” disabled, OCV taken, “BAT_GD enabled.) Battery Volt Sufficient to FG? NORMAL SLEEP Batt Present IT Operations (dsg, chg, rlx) Icc > -OR- standby >...

  • Page 26: Temperature Measurement

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 5.4 TEMPERATURE MEASUREMENT The bq27500/1 measures battery temperature via its TS input, in order to supply battery temperature status information to Impedance Track™ 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 Operation Configuration register is cleared.

  • Page 27: Power Modes

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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.
  • Page 28 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 BAT INSERT CHECK Check for battery insertion from HALT state . No gauging Flags [BAT _DET ] =0 = Sleep Exit From HIBERNATE (Communication Activity Comm address is for bq27500/1) Entry to NORMAL Battery Removed Flags [ BAT _DET] =1...

  • Page 29: Power Control

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 5.8 POWER CONTROL 5.8.1 RESET FUNCTIONS When the bq27500 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.

  • Page 30: Autocalibration

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 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 modes. Operation Configuration uses bits [RSNS1-RSNS0] to set the sense resistor selection.

  • Page 31: Application-Specific Information

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 6 APPLICATION-SPECIFIC INFORMATION 6.1 BATTERY PROFILE STORAGE AND SELECTION 6.1.1 General Profile Description When a battery pack is removed from system equipment that implements the bq27500/01, the fuel gauge will maintain some of the battery’s information in case it is re-inserted.
  • Page 32 bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 impedance is measured immediately after battery detection. The bq27500 chooses the profile which is closest to the measured impedance, starting with the Packn Ra profiles. That is, if the measured impedance matches Pack0 Ra, then the Pack0 Ra profile is used.

  • Page 33: Communications

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 7 COMMUNICATIONS 7.1 I C INTERFACE The fuel gauge supports the standard I C read, incremental read, one-byte write quick read, and functions. The 7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as 1010101.

  • Page 34: Reference Schematics

    bq27500 bq27501 System-Side Impedance Track™ Fuel Gauge www.ti.com SLUS785 – SEPTEMBER 2007 8 REFERENCE SCHEMATICS 8.1 SCHEMATIC REFERENCE SCHEMATICS Submit Documentation Feedback...
  • Page 35 PACKAGE OPTION ADDENDUM www.ti.com 25-Sep-2007 PACKAGING INFORMATION Orderable Device Status Package Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Type Drawing BQ27500DRZR ACTIVE 3000 Call TI Call TI BQ27500DRZT ACTIVE Call TI Call TI The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
  • Page 39 TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated products in automotive applications, TI will not be responsible for any failure to meet such requirements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products...

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