bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com System-Side Impedance Track™ Fuel Gauge With Integrated Sense Resistor FEATURES APPLICATIONS • • • • • • • 1 23 • • • • • Battery Fuel Gauge for 1-Series LiCoO2 battery Applications Easy to Configure Battery Fuel Gauging Based on Patented Impedance Track™ Technology – Models Battery Discharge Curve for Accurate State-of-Charge Report – Automatically Adjusts for Battery Aging, Battery Self-Discharge, and Temperature/Rate Inefficiencies – Low-Value Integrated Sense Resistor (10 mΩ typical) Resides on System Main Board – Works with Embedded or Removable Battery Packs – Integrated LDO allows devices to be powered directly from battery pack Microcontroller Peripheral Provides: – Accurate Battery Fuel Gauging – Internal Temperature Sensor for Battery Temperature Reporting – Configurable Level of State-of-Charge (SOC) Interrupts 2 I C™ for Connection to System Microcontroller Port Small 15-pin 2,69 × 1,75 mm, 0.5 mm pitch CSP package Feature Phones Smart Phones PDAs Digital Still and Video Cameras Handheld Terminals MP3 or Multimedia Players DESCRIPTION The Texas Instruments bq27425 system-side LiCoO2 battery fuel gauge is an easy to configure microcontroller peripheral that provides fuel gauging for single-cell LiCoO2 battery packs. The device requires minimal user configurations and system microcontroller firmware development for accurate fuel gauging. The bq27425 uses the patented Impedance Track™ algorithm for fuel gauging, and provides information such as remaining battery capacity (mAh), state-of-charge (%), and battery voltage (mV). Battery fuel gauging with the bq27425 requires only PACK+ (P+), PACK– (P–), for a removable battery pack or embedded battery circuit. The 15-pin 2,69 × 1,75 mm, 0.5 mm pitch CSP package is ideal for space constrained applications. TYPICAL APPLICATION Single Cell Li- Ion Battery Pack Voltage Sense VBAT VCC LDO System Interface I2C bq27425 PROTECTION IC To Charger T DATA SRX GPOUT BIN PACK + REGIN Integrated Current Sense PACK - FETs CHG DSG VSS 1 2 3 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. Impedance Track is a trademark of Texas Instruments. I2C 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. Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com 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. DEVICE INFORMATION AVAILABLE OPTIONS PART NUMBER PACKAGE (1) TA COMMUNICATION FORMAT CSP-15 –40°C to 85°C I2C bq27425YZFR-G1 bq27425YZFT-G1 (1) TAPE and REEL QUANTITY 3000 250 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. PIN DIAGRAM CSP-15 (BOTTOM VIEW) CSP-15 (TOP VIEW) A3 B3 C3 D3 E3 E3 D3 C3 B3 A3 A2 B2 C2 D2 E2 E2 D2 C2 B2 A2 A1 B1 C1 D1 E1 E1 D1 C1 B1 A1 PIN FUNCTIONS PIN NAME NO. TYPE (1) DESCRIPTION Integrated Sense Resistor and Coulomb Counter input typically connected to battery PACK- terminal. For best performance decouple with 0.1μF ceramic capacitor to Vss. SRX B1 IA VSS C1 P, IA VCC D1 P Regulator output and bq27425 processor power. Decouple with 1μF ceramic capacitor to Vss. REGIN E1 P Regulator input. Decouple with 0.1μF ceramic capacitor to Vss. CE D2 I Chip Enable. Internal LDO is disconnected from REGIN when driven low. BAT E2 I Cell-voltage measurement input. ADC input. Recommend 4.8V maximum for conversion accuracy. SCL A3 I Slave I2C serial communications clock input line for communication with system (Master). Use with 10kΩ pull-up resistor (typical). SDA B3 I/O Slave I2C serial communications data line for communication with system (Master). Open-drain I/O. Use with 10kΩ pull-up resistor (typical). BIN C3 I Battery-insertion detection input. A logic high to low transition is detected as a battery insertion event. Recommend using a pull-up resistor >1MΩ (1.8 MΩ typical) to VCC for reduced power consumption. An internal pull-up resistor option is also available using the Operation Configuration[BI_PU_EN] register bit. GPOUT A2 O General Purpose open-drain output. May be configured as a Battery Low indicator or perform SOC interrupt (SOC_INT) function. A1, B2, C2, D3, E3 IA No Connect. NC (1) 2 Device ground and Integrated Sense Resistor termination. I/O = Digital input/output, IA = Analog input, P = Power connection Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com ELECTRICAL SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VALUE UNIT VREGIN Regulator input range PARAMETER –0.3 to 5.5 V VCC Supply voltage range –0.3 to 2.75 V VIOD Open-drain I/O pins (SDA, SCL) –0.3 to 5.5 V VBAT BAT input pin –0.3 to 5.5 VI Input voltage range to all other pins (SRX , GPOUT) TA Tstg (1) –0.3 to VCC + 0.3 V Operating free-air temperature range –40 to 85 °C Storage temperature range –65 to 150 °C 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. THERMAL INFORMATION Value THERMAL METRIC (1) θJA Junction-to-ambient thermal resistance 70 θJCtop Junction-to-case (top) thermal resistance 17 θJB Junction-to-board thermal resistance 20 ψJT Junction-to-top characterization parameter 1 ψJB Junction-to-board characterization parameter 18 θJCbot Junction-to-case (bottom) thermal resistance n/a (1) UNITS YZF(15 PINS) °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953 RECOMMENDED OPERATING CONDITIONS TA = 25°C and VREGIN = VBAT = 3.6V (unless otherwise noted) PARAMETER TEST CONDITIONS No operating restrictions VREGIN Supply voltage CREGIN External input capacitor for internal LDO between REGIN and VSS CLDO25 External output capacitor for internal LDO between VCC and VSS ICC NORMAL operating-mode current (1) Fuel gauge in NORMAL mode. ILOAD > Sleep Current ISLP SLEEP mode operating mode current (1) Fuel gauge in SLEEP mode. ILOAD < Sleep Current IHIB Hibernate operating-mode current (1) Fuel gauge in HIBERNATE mode. ILOAD < Hibernate Current VOL(OD) Output low voltage on open-drain pins (SCL, SDA, GPOUT) IOL = 1 mA VOH(OD) Output high voltage on open-drain pins (SDA, SCL, GPOUT) VIL Input low voltage, all digital pins No NVM writes Input high voltage (SDA, SCL) VIH Input high voltage (BIN) VA2 Input voltage range (BAT) VA3 Input voltage range (SRX) (1) (2) (1) (2) Nominal capacitor values specified. Recommend a 5% ceramic X5R type capacitor located close to the device. External pullup resistor connected to VCC MIN TYP MAX 2.7 4.5 2.45 2.7 0.47 UNIT V 0.1 μF 1 μF 118 μA 23 μA 8 μA 0.4 VCC – 0.5 V V –0.3 0.6 V 1.2 5.5 V 1.2 VCC + 0.3 V VSS – 0.125 5 V VSS – 0.040 0.040 V Specified by design. Not production tested. Limited by ISRX maximum recommend input current with some margin for the Integrated Sense Resistor tolerance Copyright © 2011, Texas Instruments Incorporated 3 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com RECOMMENDED OPERATING CONDITIONS (continued) TA = 25°C and VREGIN = VBAT = 3.6V (unless otherwise noted) PARAMETER Ilkg Input leakage current (I/O pins) tPUCD Power-up communication delay TEST CONDITIONS MIN TYP MAX 0.3 250 UNIT μA ms POWER-ON RESET TA = –40°C to 85°C, typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER TEST CONDITIONS VIT+ Positive-going voltage on VCC (Regulator output) VHYS Power-on reset hysteresis MIN TYP MAX 1.98 2.20 2.31 UNIT V 43 115 185 mV UNIT 2.5V LDO REGULATOR TA = 25°C, CLDO25 = 1μF, VREGIN = 3.6 V (unless otherwise noted) PARAMETER TEST CONDITION MIN NOM MAX 2.5 2.6 2.5 V LDO REGULATOR (1) VREG25 Regulator output voltage VIH(CE) CE High-level input voltage VIL(CE) CE Low-level input voltage VDO Regulator dropout voltage ΔVREGTEMP ΔVREGLINE ΔVREGLOAD ISHORT (1) (2) 4 (2) 2.7V ≤ VREGIN ≤ 4.5V, IOUT ≤ 5mA TA = –40°C to 85°C 2.4 2.45V ≤ VREGIN < 2.7V (low battery), IOUT ≤ 3mA TA = –40°C to 85°C 2.4 VREGIN = 2.7 to 4.5V TA = –40°C to 85°C V 2.65 V 0.8 2.7V, IOUT ≤ 5mA TA = –40°C to 85°C 325 2.45V, IOUT ≤ 3mA TA = –40°C to 85°C 50 Regulator output change with temperature VREGIN = 3.6V, IOUT = 5mA TA = –40°C to 85°C Line regulation 2.7V ≤ VREGIN ≤ 4.5V, IOUT = 5mA 18 40 0.2mA ≤ IOUT ≤ 3mA, VREGIN = 2.45 V 34 40 3mA ≤ IOUT ≤ 5mA, VREGIN = 2.7 V 31 Load regulation Short circuit current limit V VREG25 = 0V TA = –40°C to 85°C mV 0.5% 250 mV mV mA LDO output current, IOUT, is the sum of internal and external load currents. Assured by design. Not production tested. Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com INTERNAL TEMPERATURE SENSOR CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER GTEMP TEST CONDITIONS MIN TYP MAX UNIT –2 Temperature sensor voltage gain mV/°C INTEGRATING ADC (COULOMB COUNTER) CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER VSR Input voltage range tSR_CONV Conversion time TEST CONDITIONS (1) (2) VSR = V(SRX) – VSS MIN Single conversion Input offset INL Integral nonlinearity error ZIN(SR) Effective input resistance (1) Ilkg(SR) Input leakage current (1) UNIT V s 14 VOS(SR) MAX 0.040 1 Resolution (1) (2) TYP –0.040 15 bits μV 10 ±0.007 ±0.034 2.5 % FSR MΩ TA = 25°C 0.3 μA Specified by design. Not tested in production. Limited by ISRX maximum recommend input current with some margin for the Integrated Sense Resistor tolerance. INTEGRATED SENSE RESISTOR CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX SRXRES Resistance of Integrated Sense Resistor from SRX to VSS. (1) (2) TA = 25°C ISRX Recommended Sense Resistor input current. (1) (3) Long term RMS, average device utilization. 1000 mA Peak RMS current, 10% device utilization. (3) 2500 mA Peak pulsed current, 250mS max, 1% device utilization. (3) 3500 mA MAX UNIT (1) (2) (3) 10 UNIT mΩ Specified by design. Not tested in production. Firmware compensation applied for temperature coefficient of resistor. Device utilization is the long term usage profile at a specific condition compared to the average condition. ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER VIN(ADC) Input voltage range tADC_CONV Conversion time TEST CONDITIONS Resolution VOS(ADC) Effective input resistance (BAT) (1) Ilkg(ADC) Input leakage current (1) TYP 1 14 Input offset ZADC (1) MIN 0.05 ms 15 bits 1 Not measuring cell voltage Measuring cell voltage TA = 25°C V 125 mV 8 MΩ 100 kΩ 0.3 μA Specified by design. Not tested in production. Copyright © 2011, Texas Instruments Incorporated 5 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com EEPROM MEMORY CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP Array Size 256 Data retention (1) Programming write cycles (1) (1) MAX UNIT Bytes 10 Years 100K Cycles Specified by design. Not production tested I2C-COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS TA = –40°C to 85°C; typical values at TA = 25°C and VREGIN = 3.6 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 300 ns 300 ns tr SCL/SDA rise time tf SCL/SDA fall time tw(H) SCL pulse duration (high) 600 ns tw(L) SCL pulse duration (low) 1.3 μs tsu(STA) Setup for repeated start 600 ns td(STA) Start to first falling edge of SCL 600 ns tsu(DAT) Data setup time 100 ns th(DAT) Data hold time 0 ns tsu(STOP) Setup time for stop t(BUF) Bus free time between stop and start fSCL Clock frequency 600 ns 66 μs 400 tSU(STA) tw(H) tf tw(L) tr kHz t(BUF) SCL SDA td(STA) tsu(STOP) tf tr REPEATED START th(DAT) tsu(DAT) STOP START Figure 1. I2C-Compatible Interface Timing Diagrams 6 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com GENERAL DESCRIPTION The bq27425 accurately predicts the battery capacity and other operational characteristics of a single LiCoO2 rechargeable cell. It can be interrogated by a system processor to provide cell information, such as state-of-charge (SOC). 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 bq27425 control and status registers, as well as its data locations. Commands are sent from system to gauge using the bq27425’s I2C serial communications engine, and can be executed during application development, pack manufacture, or end-equipment operation. The key to the bq27425’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 high accuracy across a wide variety of operating conditions and over the lifetime of the battery. The bq27425 measures charge/discharge activity by monitoring the voltage across a small-value integrated sense resistor (10 mΩ typical) located between the system’s Vss and the battery’s PACK– terminal. When a cell is attached to the bq27425, cell impedance is computed, based on cell current, cell open-circuit voltage (OCV), and cell voltage under loading conditions. The bq27425 utilizes an integrated temperature sensor for estimating cell temperature. Alternatively, the host processor can provide temperature data for the bq27425. To minimize power consumption, the bq27425 has several power modes: INITIALIZATION, NORMAL, SLEEP, and HIBERNATE. The bq27425 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 RemainingCapacity( ). NVM Data: italics, bold, and breaking spaces, e.g. Design Capacity. Register bits and flags: brackets and italics, e.g. [TDA] NVM Data bits: brackets, italics and bold, e.g: [LED1] Modes and states: ALL CAPITALS, e.g. UNSEALED mode. Copyright © 2011, Texas Instruments Incorporated spaces, e.g. 7 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com DATA COMMANDS Standard Data Commands The bq27425 uses a series of 2-byte standard commands to enable system reading and writing of battery information. Each standard command has an associated command-code pair, as indicated in Table 1. Because each command consists of two bytes of data, two consecutive I2C transmissions must be executed both to initiate the command function, and to read or write the corresponding two bytes of data. Additional options for transferring data, such as spooling, are described in Section, 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, refer to Section Access Modes.) Table 1. Standard Commands COMMAND CODE UNITS SEALED ACCESS Control( ) NAME CNTL 0x00 / 0x01 N/A R/W Temperature( ) TEMP 0x02 / 0x03 0.1°K R/W Voltage( ) VOLT 0x04 / 0x05 mV R FLAGS 0x06 / 0x07 N/A R NominalAvailableCapacity( ) NAC 0x08 / 0x09 mAh R FullAvailableCapacity( ) FAC 0x0a / 0x0b mAh R RemainingCapacity( ) RM 0x0c / 0x0d mAh R FullChargeCapacity( ) FCC 0x0e / 0x0f mAh R AverageCurrent( ) AI 0x10 / 0x11 mA R StandbyCurrent( ) SI 0x12 / 0x13 mA R MaxLoadCurrent( ) MLI 0x14 / 0x15 mA R AveragePower( ) AP 0x18 / 0x19 mW R StateOfCharge( ) SOC 0x1c / 0x1d % R IntTemperature( ) ITEMP 0x1e / 0x1f 0.1°K R SOH 0x20 / 0x21 % R Flags( ) StateofHealth( ) 8 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com 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 bq27425 during normal operation and additional features when the bq27425 is in different access modes, as described in Table 2. Table 2. Control( ) Subcommands CNTL FUNCTION CNTL DATA SEALED ACCESS CONTROL_STATUS 0x0000 Yes Reports the status of device. DEVICE_TYPE 0x0001 Yes Reports the device type (0x0410). FW_VERSION 0x0002 Yes Reports the firmware version on the device type. HW_VERSION 0x0003 Yes Reports the hardware version of the device type. PREV_MACWRITE 0x0007 No Returns previous MAC command code. BAT_INSERT 0x000c Yes Forces the [BAT_DET] bit set when the [BIE] bit is 0. BAT_REMOVE 0x000d Yes Forces the [BAT_DET] bit clear when the [BIE] bit is 0. SET_HIBERNATE 0x0011 Yes Forces CONTROL_STATUS [HIBERNATE] to 1. CLEAR_HIBERNATE 0x0012 Yes Forces CONTROL_STATUS [HIBERNATE] to 0. SET_CFGUPDATE 0x0013 No Force CONTROL_STATUS [CFGUPMODE] to 1 and gauge enters CONFIG UPDATE mode. SEALED 0x0020 No Places the bq27425 in SEALED access mode. RESET 0x0041 No Forces a full reset of the bq27425. SOFT_RESET 0x0042 No Performs a soft reset to reinitialize configuration data. Forces CONTROL_STATUS [CFGUPMODE] to 0. Copyright © 2011, Texas Instruments Incorporated DESCRIPTION 9 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com 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 Bit Definitions bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 High Byte RSVD RSVD SS CALMODE CCA BCA QMAX_UP RES_UP Low Byte RSVD HIBERNATE RSVD SLEEP LDMD RUP_DIS VOK RSVD RSVD = Reserved. SS = Status bit indicating the bq27425 is in the SEALED State. Active when set. CALMODE = Status bit indicating the bq27425 is in calibration mode. Active when set. CCA = Status bit indicating the bq27425 Coulomb Counter Auto-Calibration routine is active. The CCA routine will take place approximately 3 minutes and 45 seconds after the initialization. Active when set. BCA = Status bit indicating the bq27425 board calibration routine is active. Active when set. QMAX_UP = Status bit indicating Qmax has Updated. True when set. This bit is cleared after power on reset or when [BAT_DET] bit is set. When this bit is cleared, it enables fast learning of battery Qmax. Status bit indicating that resistance has been updated. True when set. This bit is cleared after power on reset or when RES_UP = [BAT_DET] bit is set. Also this bit can only be set after Qmax is updated or QMAXU is set. When this bit is cleared, it enables fast learning of battery impedance. HIBERNATE = Status bit indicating a request for entry into HIBERNATE from SLEEP mode has been issued. True when set. Default is 0. SLEEP = Status bit indicating the bq27425 is in SLEEP mode. True when set. LDMD = Status bit indicating the algorithm is using constant-power mode. True when set. Default is 1. Note: The bq27425 always uses constant-power mode. RUP_DIS = Status bit indicating the bq27425 Ra table updates are disabled. Updates disabled when set.. VOK = Status bit indicating cell voltages are OK for Qmax updates. True when set. 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. 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 0x0015. BAT_INSERT: 0X000C This subcommand forces the Flags() [BAT_DET] bit to set when the battery insertion detection is disabled via OpConfig[BIE=0]. In this case, the gauge does not detect battery insertion from the BIN pin’s logic state, but relies on the BAT_INSERT host subcommand to indicate battery presence in the system. This subcommand also starts Impedance Track™ gauging. BAT_REMOVE: 0X000D This subcommand forces the Flags() [BAT_DET] bit to clear when the battery insertion detection is disabled via OpConfig[BIE=0]. In this case, the gauge does not detect battery removal from the BIN pin’s logic state, but relies on the BAT_REMOVE host subcommand to indicate battery removal from the system. 10 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 www.ti.com SLUSAI6 – NOVEMBER 2011 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. CLEAR_HIBERNATE: 0x0012 Instructs the fuel gauge to force the CONTROL_STATUS[HIBERNATE] and [HIBE] bit to 0. This prevents 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_CFGUPDATE: 0x0013 Instructs the fuel gauge to set the CONTROL_STATUS[CFGUPMODE] bit to 1 and enter CONFIG UPDATE mode. This command is only available when the fuel gauge is UNSEALED. Note: A SOFT_RESET subcommand is typically used to exit CONFIG UPDATE mode for use resume normal gauging. FACTORY_RESTORE: 0X0015 Instructs the fuel gauge to reset learned resistance tables and Qmax values (default = DesignCapacity) to the default values. This command is only available when the fuel gauge is UNSEALED. SEALED: 0x0020 Instructs the fuel gauge to transition from UNSEALED state to SEALED state. The fuel gauge should always be set to SEALED state for use in end equipment. RESET : 0x0041 This command instructs the fuel gauge to perform a full device reset and reset RAM data to the default values from ROM. This command is only available when the fuel gauge is UNSEALED. SOFT_RESET : 0x0042 This command instructs the fuel gauge to perform a partial reset to reinitialize configuration data and clear the ITPOR bit of the Flags( ) register to resume normal gauging from CONFIG UPDATE mode. This command is only available when the fuel gauge is UNSEALED. Copyright © 2011, Texas Instruments Incorporated 11 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com Temperature( ): 0x02/0x03 This read-/write-word function returns an unsigned integer value of the temperature in units of 0.1 K measured by the fuel gauge. If [TEMPS] bit = 1, a write command sets the temperature to be used for gauging calculations while a read command returns to temperature previously written. If [TEMPS] bit = 0, a read command will return the internal temperature sensor value and write command will be ignored. Voltage( ): 0x04/0x05 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. Flags( ): 0x06/0x07 This read-word function returns the contents of the gas-gauge status register, depicting the current operating status. Table 4. Flags Bit Definitions bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 High Byte OT UT RSVD RSVD RSVD EEFAIL FC CHG Low Byte OCVTAKEN RSVD ITPOR CFGUPMODE BAT_DET SOC1 SOCF DSG OT = Over-Temperature condition is detected. True when set. See Over-Temperature Indication: Charge Sub-Section. UT = Under-Temperature condition is detected. True when set. See Over-Temperature Indication: Discharge Sub-Section. RSVD = Reserved. RSVD = Reserved. RSVD = Reserved. EEFAIL = EEPROM Write Fail. True when set. This bit is set after a single EEPROM write failure. All subsequent EEPROM writes are disabled. A power on reset or RESET subcommand is required to clear the bit to re-enable EEPROM writes. FC = Full-charged condition reached. True when set. CHG = (Fast) charging allowed. True when set. OCVTAKEN = Cleared on entry to relax mode and Set to 1 when OCV measurement is performed in relax RSVD = Reserved. ITPOR = Indicates a Power On Reset or RESET subcommand as occurred. True when set. This bit is cleared after the SOFT_RESET subcommand is received. CFGUPMODE = Fuel gauge is in CONFIG UPDATE mode. True when set. Default is 0. Refer to CONFIG Mode section for details. Battery insertion detected. True when set. When OpConfig[BIE]] is set, [BAT_DET] is set by detecting a logic high to low BAT_DET = transition at BIN pin. when OpConfig[BIE]] is low, [BAT_DET] is set when host issues BAT_INSERT subcommand and clear when host issues BAT_REMOVE subcommand. SOC1 = If set, StateOfCharge() <= SOC1 Set Threshold. The [SOC1] bit will remain set until StateOfCharge() >= SOC1 Clear Threshold. SOCF = If set, StateOfCharge() <= SOCF Set Threshold. The [SOCF] bit will remain set until StateOfCharge() >= SOCF Clear Threshold. DSG = Discharging detected. True when set. 12 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 www.ti.com SLUSAI6 – NOVEMBER 2011 NominalAvailableCapacity( ): 0x08/0x09 This read-only command pair returns the uncompensated (less than C/20 load) battery capacity remaining. Units are mAh. FullAvailableCapacity( ): 0x0a/0x0b This read-only command pair returns the uncompensated (less than C/20 load) capacity of the battery when fully charged. Units are mAh. FullAvailableCapacity( ) is updated at regular intervals, as specified by the IT algorithm. RemainingCapacity( ): 0x0c/0x0d This read-only command pair returns the compensated battery capacity remaining. Units are mAh. FullChargeCapacity( ): 0x0e/0f This read-only command pair returns the compensated capacity of the battery when fully charged. Units are mAh. FullChargeCapacity( ) is updated at regular intervals, as specified by the IT algorithm. AverageCurrent( ): 0x10/0x11 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. StandbyCurrent( ): 0x12/0x13 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 (default = -10mA), and after spending some time in standby, reports the measured standby current. The register value is updated every 1 second when the measured current is above the Deadband ( = ±5mA) and is less than or equal to 2 x Initial Standby (default = -10mA). The first and last values that meet this criteria are not averaged in, since they may not be stable values. To approximate a 1-minute time constant, each new StandbyCurrent( ) value is computed by taking approximate 93% weight of the last standby current and approximate 7% of the current measured average current. MaxLoadCurrent( ): 0x14/0x15 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 (default = –500mA) . 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. AveragePower( ): 0x18/0x19 This read-only function returns an signed integer value of the average power during battery charging and discharging. It is negative during discharge and positive during charge. A value of 0 indicates that the battery is not being discharged. The value is reported in units of mW. StateOfCharge( ): 0x1c/0x1d 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%. IntTemperature( ): 0x1e/0x1f This read-/write-word function returns an unsigned integer value of the internal temperature sensor in units of 0.1 K measured by the fuel gauge. If OpConfig[WRTEMP] = 0, this command will return the same value as Temperature( ). Copyright © 2011, Texas Instruments Incorporated 13 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com StateofHealth( ): 0x20/0x21 0x20 SOH percentage: this read-only function returns an unsigned integer value, expressed as a percentage of the ratio of predicted FCC(25°C, SOH LoadI) over the DesignCapacity(). The FCC(25°C, SOH LoadI) is the calculated full charge capacity at 25°C and the SOH LoadI which is programmed in factory (default = –400mA). The range of the returned SOH percentage is 0x00 to 0x64, indicating 0 to 100% correspondingly. 0x21 SOH Status: this read-only function returns an unsigned integer value, indicating the status of the SOH percentage. The meanings of the returned value are: • 0x00: SOH not valid (initialization) • 0x01: Instant SOH value ready • 0x02: Initial SOH value ready – Calculation based on uncompensated Qmax – Updated at first grid point update after cell insertion • 0x03: SOH value ready – Utilize the updated Qmax update – Calculation based on compensated Qmax – Updated after complete charge and relax is complete • 0x04-0xFF: Reserved 14 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com 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 command bytes for a given extended command ranges in size from single to multiple bytes, as specified in Table 5. Table 5. Extended Commands NAME OperationConfiguration( ) DesignCapacity( ) COMMAND CODE UNITS SEALED ACCESS (1) (2) UNSEALED ACCESS (1) (2) OPCFG 0x3a / 0x3b N/A R R/W DCAP 0x3c / 0x3d mAh R R/W 0x3e N/A N/A R/W DataClass( ) (2) DFCLS DataBlock( ) (2) DFBLK 0x3f N/A R/W R/W DFD 0x40…0x5f N/A R R/W DFDCKS 0x60 N/A R/W R/W BlockData( ) BlockDataCheckSum( ) BlockDataControl( ) DeviceNameLength( ) DeviceName( ) Reserved (1) (2) DFDCNTL 0x61 N/A N/A R/W DNAMELEN 0x62 N/A R R DNAME 0x63...0x69 N/A R R RSVD 0x6a...0x7f N/A R R SEALED and UNSEALED states are entered via commands to Control( ) 0x00/0x01 In sealed mode, data CANNOT be accessed through commands 0x3e and 0x3f. OperationConfiguration( ): 0x3a/0x3b SEALED and UNSEALED Access: This command returns the Operation Configuration register setting DesignCapacity( ): 0x3c/0x3d SEALED and UNSEALED Access: This command returns 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 and is used as an input for the algorithm to scale the normalized resistance tables. DataClass( ): 0x3e UNSEALED Access: This command sets the data class to be accessed. The class to be accessed should be entered in hexadecimal. SEALED Access: This command is not available in SEALED mode. DataBlock( ): 0x3f UNSEALED Access: This command sets the data block to be accessed. When 0x00 is written to BlockDataControl( ), DataBlock( ) holds the block number of the data to be read or written. Example: writing a 0x00 to DataBlock( ) specifies access to the first 32 byte block and a 0x01 specifies access to the second 32 byte block, and so on. SEALED Access: This command directs which data block will be accessed by the BlockData( ) command. Issuing a 0x01 instructs the BlockData( ) command to transfer Manufacturer Info Block A. BlockData( ): 0x40…0x5f UNSEALED Access: This data block is the remainder of the 32 byte data block when accessing general block data. SEALED Access: This data block is the remainder of the 32 byte data block when accessing Manufacturer Info Block. Copyright © 2011, Texas Instruments Incorporated 15 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com BlockDataChecksum( ): 0x60 UNSEALED Access: This byte contains the checksum on the 32 bytes of block data read or written. 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. 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. BlockDataControl( ): 0x61 UNSEALED Access: This command is used to control the data access mode. Writing 0x00 to this command enables BlockData( ) to access general data NVM. Writing a 0x01 to this command enables SEALED mode operation of DataBlock( ). SEALED Access: This command is not available in SEALED mode. DeviceNameLength( ): 0x62 UNSEALED and SEALED Access: This byte contains the length of the Device Name. DeviceName( ): 0x63…0x69 UNSEALED and SEALED Access: This block contains the device name that is programmed in Device Name Reserved – 0x6a – 0x7f BLOCK DATA INTERFACE Accessing Block Data The bq27425 contains both re-writable EEPROM non-volatile memory (NVM) and ROM-based data blocks. Upon device RESET, the ROM-based data blocks are copied to associated volatile RAM space to initialize default configuration and data constants to be used by the fuel gauging algorithm. Re-writable NVM-based data blocks contain information expected to change such as: calibration, customer data and Impedance Track fuel gauging data tables. If the application requires a change to the NVM or RAM configuration data, the host can update the data blocks in CONFIG UPDATE mode. RAM-based data changes are temporary and must be applied by the host using CONFIG UPDATE mode after each device RESET; while changes to the NVM data blocks are permanent. The data blocks can be accessed in several different ways, depending on the access mode and what data is being accessed. Commonly accessed data block locations, frequently read by a system, are conveniently accessed through specific instructions, already described in Section Data Commands. These commands are available when the bq27425 is either in UNSEALED or SEALED modes. Most data block locations, however, are only accessible in UNSEALED mode by use of the bq27425 evaluation software or by data block transfers. These locations should 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 locations individually, the block containing the desired data NVM location(s) must be transferred to the command register locations, where they can be read to the system or changed directly. This is accomplished by sending the set-up 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 the associated data block, once the correct checksum for the whole block is written to BlockDataChecksum( ) (0x60). 16 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com Occasionally, a data CLASS will be larger than the 32-byte block size. In this case, the DataBlock( ) command is used to designate which 32-byte block the desired locations reside in. The correct command address is then given by 0x40 + offset modulo 32. For example, to access Terminate Voltage in the Gas Gauging class, DataClass( ) is issued 80 (0x50) to set the class. Because the offset is 48, it must reside in the second 32-byte block. Hence, DataBlock( ) 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. None of the data written to memory are bounded by the bq27425, 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 data written to NVM blocks is persistent, so a power-on reset does not resolve the fault. ACCESS MODES The bq27425 provides three security modes (FULL ACCESS, UNSEALED, and SEALED) that control data NVM access permissions according to Table 6. Although FULL ACCESS and UNSEALED modes appear identical, only FULL ACCESS mode allows the bq27425 to write access-mode transition keys. Table 6. Data NVM Access Security Mode Data NVM Manufacturer Info FULL ACCESS R/W R/W UNSEALED R/W R/W SEALED None R SEALING/UNSEALING DATA BLOCKS The bq27425 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 bq27425 via the Control( ) control command. The keys must be sent consecutively, with no other data being written to the Control( ) register in between. Note that to avoid conflict, the keys must be different from the codes presented in the CNTL DATA column of Table 2 subcommands. When in SEALED mode the [SS] bit of CONTROL_STATUS is set, but when the UNSEAL keys are correctly received by the bq27425, 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 ROM. 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 1st and 2nd word of the UnSeal Key 0 returns 0x1234 and 0x5678, then Control( ) should supply 0x3412 and 0x7856 to unseal the part. Copyright © 2011, Texas Instruments Incorporated 17 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com BLOCK DATA SUMMARY Table 7 summarizes the data blocks available to the user, including their default, minimum, and maximum values. Table 7. Block Data Summary Class Configuration [RAM] SubClass ID SubClass Offset 2 Safety [RAM] 0 Over Temp 2 4 36 49 68 Charge Termination [RAM] Discharge [RAM] Power [RAM] Name Data Type Min Max Default Unit (EVSW Unit) I2 -1200 1200 550 0.1°C Under Temp I2 -1200 1200 0 0.1°C Temp Hys U1 0 255 50 0.1°C 0 Min Taper Capacity I2 0 1000 25 mAh 2 Current Taper Window U1 0 60 40 mV 3 TCA Set % I1 -1 100 99 % 4 TCA Clear % I1 -1 100 95 % 5 FC Set % I1 -1 100 100 % 6 FC Clear % I1 -1 100 98 % 0 SOC1 Set Threshold U1 0 255 10 % 1 SOC1 Clear Threshold U1 0 255 15 % 2 SOCF Set Threshold U1 0 255 2 % 3 SOCF Clear Threshold U1 0 255 5 % 9 Hibernate I I2 0 700 3 mA 11 Hibernate V I2 2400 3000 2550 mV Block A 0-11 H1 0x0 0xff 0x0 System Data [NVM] 58 Manufacturer Info [NVM] 0-11 Gas Gauging [NVM/RAM] 80 IT Cfg [RAM] 41 User Rate-mA I2 2000 9000 0 mV 43 User Rate-mW I2 3000 14000 0 CentiW 45 Reserve Cap-mWh I2 0 14000 0 cWattHour 0 Dsg Current Threshold I2 0 2000 167 mA 2 Chg Current Threshold I2 0 2000 133 mA 4 Quit Current I2 0 1000 250 mA 3 Reserve Cap-mAh I2 0 9000 0 mAh 81 82 Ra Tables [NVM/RAM] 18 Current Thresholds [RAM] State [NVM] - 5 Op Config H2 0x0000 0xFFFF 0x01F8 Hex 12 Design Capacity I2 0 32767 1340 mAh 14 Design Energy I2 0 32767 4960 mWh 18 Terminate Voltage I2 2800 3700 3200 mV 30 Taper Current I2 0 1000 75 mA 32 Taper Voltage I2 0 5000 4100 mV 34 Sleep Current I2 0 100 10 mA 88 R_a [NVM] 0 - 28 Cell0 R_a 0-14 I2 Table Table Table 2^–10Ω (num) 89 R_a [RAM] 0 - 28 Cell0 R_a 0-14 I2 Table Table Table 2^–10Ω (num) Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com Table 7. Block Data Summary (continued) Class Calibration [NVM] Security [RAM] SubClass ID SubClass Offset 104 Data [NVM] 0 CC Delta F4 2.98E+04 1.19E+06 567744.5 68 4 CC Offset U2 0 65535 –1200 num (mV) 6 Board Offset I1 –128 127 0 num (uV) 7 Int Temp Offset I1 –128 127 0 num (°C) 8 Pack V Offset I1 –128 127 0 num (mV) 0 CC Gain F4 1.00E-01 4.00E+01 0.4768 4 CC Cal Temp I2 0 32767 2982 0 Sealed to Unsealed H4 0x0 0xffffffff x367204 14 105 CC Cal [NVM] 112 Codes [RAM] Name Data Type Min Max Default Unit (EVSW Unit) num (2^–10Ω) Num (2^–10Ω) 0.1K - FUNCTIONAL DESCRIPTION FUEL GAUGING The bq27425 is an easy to configure fuel gauge that measures the cell voltage, temperature, and current to determine battery state of charge (SOC). The bq27425 monitors charge and discharge activity by sensing the voltage across a small-value resistor (5 mΩ to 20 mΩ typ.) between the SRX and VSS pins and in series with the cell. By integrating charge passing through the 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 the Design Capacity. The bq27425 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 Terminate Voltage. NominalAvailableCapacity( ) and FullAvailableCapacity( ) are the uncompensated (no or light load) versions of RemainingCapacity( ) and FullChargeCapacity( ) respectively. In addition, a FACTORY_RESTORE subcommand is provided to restore default resistance and Qmax to factory condition. FUEL GAUGING CONFIGURATIONS The bq27425 features easy to configure data NVM to speed-up fuel gauging design. Users are required to configure Design Capacity, Termination Voltage, and Operation Configuration (see The Operation Configuration Register section for details) to achieve optimal performance. The Impedance Track™ algorithm uses these parameters with it’s built-in parameters to achieve accurate battery fuel gauging. Several built-in parameters are used in the Impedance Track™ algorithm to identify different modes of battery: • Charging : Chg Current Threshold (default = DesignCapacity /13.3 ), • Discharging: Dsg Current Threshold (default = DesignCapacity /16.7 ) • Relax: Quit Current Threshold (default = DesignCapacity /25.0 ) To achieve accurate fuel gauging, the bq27425 uses Constant Power Model for fuel gauging. This model uses the average discharge power from the beginning of the discharge cycle until present time to compute load-compensated capacity such as RemainingCapacity( ) and FullChargeCapacity( ) in the Impedance Track™ algorithm. Copyright © 2011, Texas Instruments Incorporated 19 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com DETAILED PIN DESCRIPTIONS The Operation Configuration Register Two bq27425 pins are configured via the Operation Configuration data NVM register, as indicated in Table 8. This register is programmed/read via the methods described in Section Accessing the Data NVM. Table 8. Operation Configuration Bit Definition bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 High Byte INTSNSEN RSVD0 BIE BI_PU_EN GNDSEL RSVD0 RSVD0 RSVD1 Low Byte RSVD1 RSVD1 SLEEP RMFCC RSVD1 BATLOWEN GPIOPOL WRTEMP INTSNSEN = Enables temperature compensation of the integrated sense resistor. Default is 0. BIE = Battery Insertion Enable. If set, the battery insertion is detection via BIN pin input. If cleared, the detection relies on the host to issue BAT_INSERT subcommand to indicate battery presence in the system. Default is 0. BI_PU_EN = Enables internal weak pull-up on BIN pin. Default is 0 which assumes an external pull-up resistor. GNDSEL = The ADC ground select control. The Vss (Pin D1) is selected as ground reference when the bit is clear. Pin A1 is selected when the bit is set. Default is 0. 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. BATLOWEN = If set, the BAT_LOW function for GPOUT pin is selected. If cleared, the SOC_INT function is selected for GPOUT. Default is 0. GPIO_POL = GPOUT pin is active-high if set or active-low if cleared. Default is 0. WRTEMP = Enables the host to write Temperature( ) if set. If cleared, the internal temperature sensor is used for Temperature( ). Default is 0. RSVD0 = Reserved. Default is 0. (Set to 0 for proper operation) RSVD1 = Reserved. Default is 1. (Set to 1 for proper operation) GPOUT Pin The GPOUT Pin is a multiplex pin and the polarity of the pin output can be selected via the [GPIO_POL] bit of the Operation Configuration. The function is defined by [BATLOWEN]. If set, the Battery Low Indicator (BAT_LOW) function for GPOUT pin is selected. If cleared, the SOC interrupt (SOC_INT) function is selected for GPOUT. When the BAT_LOW function is activated, the signaling on the multiplexed pin follows the status of the [SOC1] bit in the Flags( ) register. The bq27425 has two flags accessed by the Flags( ) function that warns when the battery’s SOC has fallen to critical levels. When StateOfCharge( ) 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 StateOfCharge( ) rises above SOC1 Set Threshold. The bq27425’s GPOUT pin automatically reflects the status of the [SOC1] flag when OpConfig[BATLOWEN=0]. When StateOfCharge( ) falls below the second capacity threshold, SOCF Set Threshold, the [SOCF] (State of Charge Final) flag is set, serving as a final discharge warning. Similarly, when StateOfCharge( ) rises above SOCF Clear Threshold and the [SOCF] flag has already been set, the [SOCF] flag is cleared. When the SOC_INT function is activated, the GPOUT pin generates 1ms pulse width under various conditions as described in Table 9. 20 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com Table 9. SOC_INT Function Definition SOCI_Delta Enable Condition Pulse Width Description SOCI_Delta ≠ 0 1ms During charge, when the StateOfCharge() reaches greater than or equal to (≥) the defined SOC_INT intervals. The intervals are defined as 100% and 100% – n × SOCI_Delta. During discharge, when the StateOfCharge() reaches less than (<) the defined SOC_INT intervals. The intervals are defined as 0% and 100% – n × SOCI_Delta. n: Integer value starting from 0. For SOCI_Delta = 10%, the SOC_INT intervals are 0%, 10%, 20%, ….. 90%, and 100%. State Change SOCI_Delta ≠ 0 1ms When there is a state change including charging, discharging, and relaxation. Battery Removal [BIE] bit is set in OpConfig 1ms When battery removal is detected by BIN pin. Battery Detection (BIN) The host is responsible for battery detection by setting the [BAT_DET] bit to trigger INITIALIZATION mode. The function of OpConfig[BIE] bit is described in Table 10. When battery insertion is detected and INITIALIZATION mode is completed, the bq27425 runs in NORMAL mode to start Impedance Track™ fuel gauging. When battery insertion is not detected, fuel gauging is stopped. Table 10. Battery Detection OpConfig[BIE] Battery Insertion Requirement Battery Removal Requirement 1 (1) Host drives BIN pin from logic high to low to signal battery insertion. or (2) A weak pull-up resistor can be used (between BIN and VCC pin). When battery pack with pull-down is connected, it can generate a logic low to signal battery insertion. (1) Host drives BIN pin from logic low to high to signal battery removal. or (2) When battery pack with pull-down is removed, the weak pull-up resistor can generate a logic high to signal battery removal. 0 Host sends BAT_INSERT subcommand to signal battery insertion. Host sends BAT_REMOVE subcommand to signal battery removal. TEMPERATURE MEASUREMENT The bq27425 measures temperature using an on-chip temperature sensor. Alternatively if [WRTEMP] = 1, the host sends temperature data to the gauge with the initial default setting at 25°C. Regardless of [WRTEMP] setting, the fuel gauge uses temperature data in Temperature() command for fuel gauging. Over-Temperature Indication: Charge If during charging, Temperature( ) reaches the threshold of OT Chg (default = 55°C) for a period of OT Chg Time (default = 2 seconds) and AverageCurrent( ) > Chg Current Threshold (default = DesignCapacity / 13.3), then the [OTC] bit of Flags( ) is set. When Temperature() falls to OT Chg Recovery (default = 50°C), the [OTC] of Flags() is reset. Over-Temperature Indication: Discharge If during discharging, Temperature( ) reaches the threshold of OT Dsg (default = 60°C) for a period of OT Dsg Time (default = 2 seconds) , and AverageCurrent( ) ≤ -Dsg Current Threshold (default = DesignCapacity /16.7 ) , then the [OTD] bit of Flags( ) is set. When Temperature( ) falls to OT Dsg Recovery (default = 55°C), the [OTD] bit of Flags( ) is reset. Copyright © 2011, Texas Instruments Incorporated 21 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com DETECTING CHARGE TERMINATION The bq27425 detects charge termination when (1) during 2 consecutive periods of Current Taper Window (default = 40 seconds), the AverageCurrent( ) is < Taper Current (default = 100 mA), (2) during the same periods, the accumulated change in capacity > 0.25mAh/ / Current Taper Window (default = 40 seconds), and (3) Voltage( ) > (Charging Voltage – 100mV) where Charging Voltage = 4200mV by default. When this occurs, the [CHG] bit of Flags( ) is cleared. Also, if the [RMFCC] bit of Operation Configuration is set, and RemainingCapacity( ) is set equal to FullChargeCapacity( ). Charge Inhibit The bq27425 can indicate when battery temperature has fallen below or risen above predefined thresholds Charge Inhibit Temp Low (default = 0˚C) or Charge Inhibit Temp High (default = 45˚C), respectively. In this mode, the [CHG_INH] of Flags( ) is made high to indicate this condition, and is returned to its low state, once battery temperature returns to the range [Charge Temp Low, Charge Temp High] (default = [5˚C,40˚C]). OPERATING MODES The bq27425 has different operating modes: POR, INITIALIZATION, NORMAL, CONFIG UPDATE, SLEEP, and HIBERNATE. Following Power On Reset (POR), the fuel gauge begins INITIALIZATION. In NORMAL mode, the bq27425 is fully powered and can execute any allowable task. Configuration data in RAM and NVM can be updated by the host using the CONFIG UPDATE mode. In SLEEP mode the fuel gauge turns off the high frequency oscillator clock to enter a reduced-power state, periodically taking measurements and performing calculations. In HIBERNATE mode, the fuel gauge is in a very low power state, but can be woken up by communication or certain I/O activity. via RESET subcommand (from any mode) Power On Reset [POR] Copy configuration ROM defaults to RAM data. Set Flags[ITPOR] = 1. Exit from CONFIG UPDATE Flags [CFGUPMODE] = 0 AND Flags [ITPOR] = 0 INITIALIZATION Flags [BAT _ DET ] = 0 (via SOFT_RESET subcommand) Initialize algorithm and data.. Check for battery insertion. . (No gauging in this mode.) CONFIG UPDATE Host can change RAM and NVM based data blocks. (No gauging in this mode.) I CC = Normal Entry to CONFIG UPDATE Flags [CFGUPMODE] = 1 (via SET_CFGUPDATE subcommand) Exit From NORMAL Entry to NORMAL Flags [ BAT _ DET ] = 1 Flags [BAT _ DET ] = 0 Exit From HIBERNATE V CELL < POR threshold NORMAL Exit From HIBERNATE Communication Activity OR bq27425 clears Control Status [HIBERNATE ] = 0 Recommend Host also set Control Status [HIBERNATE ] = 0 HIBERNATE Wakeup From HIBERNATE Communication to gauge AND Comm address is NOT for bq27425 Disable all subcircuits except GPIO . Fuel gauging and data updated every 1s Exit From SLEEP /FULLSLEEP Pack Configuration [SLEEP ] = 0 OR | AverageCurrent ( ) | > Sleep Current OR Current is Detected above I WAKE ICC = Normal Entry to SLEEP Pack Configuration [SLEEP ] = 1 AND | AverageCurrent ( ) | = Sleep Current SLEEP Fuel gauging and data updated every 20 seconds I CC = Hibernate I CC = Sleep Exit From WAIT _HIBERNATE Host must set Control Status [HIBERNATE ] = 0 AND VCELL > Hibernate Voltage Exit From WAIT _ HIBERNATE Cell relaxed AND | AverageCurrent () | < Hibernate Current OR V CELL Cell relaxed AND < Hibernate Voltage WAIT _HIBERNATE System Sleep Fuel gauging and data updated every 20 seconds Exit From SLEEP ( Host has set Control Status [HIBERNATE ] = 1 OR VCELL < Hibernate Voltage I CC = Sleep /FullSleep System Shutdown Figure 2. Power Mode Diagram 22 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 www.ti.com SLUSAI6 – NOVEMBER 2011 POR and INITIALIZATION Modes Upon Power On Reset (POR), the fuel gauge copies ROM-based configuration defaults to RAM and begins INITIALIZATION mode where essential data is initialized and will remain in INITIALIZATION mode as halted-CPU state when an adapter, or other power source is present to power the bq27425 (and system), yet no battery has been detected. The occurrence of POR or a Control( ) RESET subcommand will set the Flags( ) [ITPOR] status bit to indicate that RAM has returned to ROM default data. When battery insertion is detected, a series of initialization activities begin including an OCV measurement. In addition CONTROL_STATUS[QMAXU] and [RESU] bits are cleared to allow fast learning of Qmax and impedance. Some commands, issued by a system processor, can be processed while the bq27425 is halted in this mode. The gauge will wake up to process the command, and then return to the halted state awaiting battery insertion. The current consumption of INITIALIZATION mode is similar to NORMAL mode. CONFIG UPDATE Mode If the application requires different configuration data for the bq27425. The host can update both NVM and RAM based parameters using the Control( ) SET_CFGUPDATE subcommand to enter CONFIG UPDATE mode as indicated by the Flags( ) [CFGUPMODE] status bit. In this mode, fuel gauging is suspended while the host uses the Extended Data Commands to modify the configuration data blocks. To resume fuel gauging, the host sends a Control( ) SOFT_RESET subcommand to return to the INITIALIZATION mode and clear both Flags( ) [ITPOR] and [CFGUPMODE] bits. 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. 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 (default = 10mA). Once entry into SLEEP mode has been qualified, but prior to entering it, the bq27425 performs an ADC autocalibration to minimize offset. During SLEEP mode, the bq27425 periodically takes data measurements and updates its data set. However, a majority of its time is spent in an idle condition. The bq27425 exits SLEEP if any entry condition is broken, specifically when: AverageCurrent( ) rises above Sleep Current (default = 10mA). HIBERNATE Mode HIBERNATE mode could be used when the system equipment needs to enter a very 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 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. The gauge will remain in HIBERNATE mode until the system issues a direct I2C command to the gauge. I2C Communication that is not directed to the gauge will not wake the gauge (or at least for very long). It is the system’s responsibility to wake the bq27425 after it has gone into HIBERNATE mode and prevents a charger from charging the battery before the [OCVTAKEN] bit is set which signals an OCV reading is taken. After waking, the gauge can proceed with the initialization of the battery information. Copyright © 2011, Texas Instruments Incorporated 23 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com I2C INTERFACE The bq27425 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 S ADDR[6:0] 0 A bq27425 generated CMD[7:0] A DATA [7:0] A P S ADDR[6:0] (a) 1-byte write S ADDR[6:0] 0 A 1 A DATA [7:0] N P (b) quick read CMD[7:0] A Sr ADDR[6:0] 1 A DATA [7:0] N P (c) 1- byte read S ADDR[6:0] 0 A CMD[7:0] A Sr ADDR[6:0] 1 A DATA [7:0] A ... DATA [7:0] N P (d) incremental read S ADDR[6:0] 0 A CMD[7:0] A DATA [7:0] A DATA [7:0] A ... A P (e) incremental write (S = Start, Sr = Repeated Start, A = Acknowledge, N = No Acknowledge, and P = Stop). Figure 3. Supported I2C Formats The "quick read" returns data at the address indicated by the address pointer. The address pointer, a register internal to the I2C communication engine, increments whenever data is acknowledged by the bq27425 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): S ADDR[6:0] 0 A CMD[7:0] A DATA[7:0] N P Attempt to read an address above 0x6B (NACK command): S 24 ADDR[6:0] 0 A CMD[7:0] N P Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com I2C Command Waiting Time To make sure the correct results of a command with the 400KHz I2C operation, a proper waiting time should be added between issuing command and reading results. For Subcommands, the following diagram shows, as an example, the 66 µs waiting time required between issuing the control command and reading the status data. Similarly, a 100 ms waiting time is required between the BlockDataChecksum( ) Extended command. For read-write Standard Commands, such as Temperature( ), a minimum of 2 seconds is needed to observe the data read back following the associated data write. For read-only standard commands, there is no waiting time required; however, the host should not issue all standard commands more than two times per second. Otherwise, the gauge could result in a reset issue due to the expiration of a watchdog timer. S ADDR [6:0] 0 A CMD [7:0] A S ADDR [6:0] 0 A CMD [7:0] A Sr DATA [7:0] ADDR [6:0] A 1 A DATA [7:0] DATA [7:0] A P A 66ms DATA [7:0] N P DATA [7:0] A 66ms Waiting time between control subcommand and reading results S ADDR [6:0] DATA [7:0] 0 A A CMD [7:0] DATA [7:0] A Sr N P ADDR [6:0] 1 A DATA [7:0] A 66ms Waiting time between continuous reading results I2C Clock Stretching I2C clock stretches can occur during all modes of fuel gauge operation. In the SLEEP and HIBERNATE modes, a short clock stretch of approximately 75 µs will occur on all I2C traffic as the device must wake-up to process the packet. In NORMAL mode, clock stretching will only occur for packets addressed for the fuel gauge. The timing of stretches will vary as interactions between the communicating host and the gauge are asynchronous. The I2C clock stretches may occur after start bits, the ACK/NAK bit and first data bit transmit on a host read cycle. The majority of clock stretch periods are small (<= 4mSec) as the I2C interface peripheral and CPU firmware perform normal data flow control. However, very infrequent clock stretch periods of up to 144 ms maximum may occur if the host issues an I2C command while the gauge is asynchronously updating NVM data tables. Copyright © 2011, Texas Instruments Incorporated 25 bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com 0.01 REFERENCE SCHEMATIC 26 Copyright © 2011, Texas Instruments Incorporated bq27425-G1 SLUSAI6 – NOVEMBER 2011 www.ti.com Package Dimensions D E Max = 2720 µm Max = 1780 µm Min = 2660 µm Min = 1720 µm Copyright © 2011, Texas Instruments Incorporated 27 PACKAGE OPTION ADDENDUM www.ti.com 23-Nov-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) Samples (Requires Login) BQ27425YZFR-G1 ACTIVE DSBGA YZF 15 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM BQ27425YZFT-G1 ACTIVE DSBGA YZF 15 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM (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 PACKAGE MATERIALS INFORMATION www.ti.com 22-Nov-2011 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) BQ27425YZFR-G1 DSBGA YZF 15 3000 180.0 8.4 BQ27425YZFT-G1 DSBGA YZF 15 250 180.0 8.4 Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 2.0 2.8 0.7 4.0 8.0 Q1 2.0 2.8 0.7 4.0 8.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 22-Nov-2011 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) BQ27425YZFR-G1 DSBGA YZF 15 3000 210.0 185.0 35.0 BQ27425YZFT-G1 DSBGA YZF 15 250 210.0 185.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and applications using TI components. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety-critical applications. TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are designated by 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 Applications Audio www.ti.com/audio Communications and Telecom www.ti.com/communications Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps DLP® Products www.dlp.com Energy and Lighting www.ti.com/energy DSP dsp.ti.com Industrial www.ti.com/industrial Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical Interface interface.ti.com Security www.ti.com/security Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive Microcontrollers microcontroller.ti.com Video and Imaging RFID www.ti-rfid.com OMAP Mobile Processors www.ti.com/omap Wireless Connectivity www.ti.com/wirelessconnectivity TI E2E Community Home Page www.ti.com/video e2e.ti.com Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2011, Texas Instruments Incorporated