bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 Single Chip 3 or 4 Cell Li-Ion Battery Management Controller With PowerPump™ Cell Balancing Technology FEATURES 1 • Advanced SmartSafety™ – Prevention – Optimal Cell Management – Diagnosis – Improved Sensing of Cell Problems – Fail Safe – Detection of Event Precursors • Rate-of-Change Detection of all Important Cell Characteristics: – Voltage – Impedance – Cell Temperature • PowerPump™ Active Cell Balancing Results in Longer Run Time and Cell Life • High Resolution 18-Bit Integrating Delta-Sigma Coulomb Counter for Precise Charge-Flow Measurements and Gas Gauging • Multiple Independent Δ-Σ A/Ds: One-per-cell Voltage, Plus Separate Temperature, Current and Safety • Simultaneous, Synchronous Measurement of Pack Current and Individual Cell Voltages • Very Low Power Consumption: < 250 µA Active, < 150 µA Standby, < 40 µA Ship, and < 1 A Under-Voltage Shutdown • Accurate, Advanced Temperature Monitoring of Cells and MOSFETs With up to 13 Sensors • Fully Programmable Voltage, Current, Balance and Temperature Protection Features • Cell Balancing Transfers Charge Efficiently From Cell to Cell During all Operating Conditions • Fail-Safe Operation of Pack Protection Circuits and MOSFETs • Designed for 3 to 4 Series Cell Battery Packs • Smart Battery System 1.1 Compliant • Integrated Support for Intel™ AMPS • Field Upgradeable Flash Memory 23 APPLICATIONS • • • Notebook Computer Battery Packs Portable Medical Equipment Portable Test Equipment DESCRIPTION The bq6400 Battery Management Controller is a complete Li-Ion control, monitoring, and safety solution designed for notebook computers and portable equipment. It is designed specifically to provide an enhanced, optimized solution for packs using three or four series cells. The bq6400 provides accurate gas gauging while providing control, communications and safety functions for the system. It provides simultaneous, synchronized voltage and temperature measurements using one A/D per-cell technology. Voltage measurements are also simultaneous with pack current measurements, eliminating system induced noise from measurements. This allows the precise, continuous, real-time calculation of cell impedance under all operating conditions, even during widely fluctuating loads. PowerPump™ technology transfers charge between cells to balance their voltage and capacity. Balancing is programmable during all battery modes: Charge, discharge, and rest. Highly efficient charge transfer circuitry nearly eliminates energy loss while providing true real-time balance between cells, resulting in longer run-time and improved cell cycle life. Temperature is sensed by one internal and up to 12 external sensors. This permits accurate temperature monitoring of each cell individually as well as pack protection MOSFETs. Internal firmware is then able to compensate for the temperature induced effects on cell capacity, impedance, and OCV on a cell-by-cell basis, resulting in superior charge/discharge and balancing control. Support for Intel™ Adaptive Mobile Power System (AMPS) requirements for battery and MOSFET control is built-in. User definable inputs require no external hardware translation logic. The bq6400 is completely user-configurable with parametric tables in flash memory to suit a variety of cell chemistries, operating conditions, safety control, and data reporting needs. It is easily configured using the supplied Battery Wizard™ graphical user interface. The device is fully programmed and requires no algorithm or firmware development. 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. PowerPump, SmartSafety are trademarks of Texas Instruments. Intel is a trademark of Intel 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 © 2008, Texas Instruments Incorporated bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... 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. Voltage Balance Temp V1 PUMP 1 XT1* Voltage Balance Temp 1 Level Safety & FET Control FLASH CELL 3 V2 PUMP 2 XT2* EFCIC 8 bit RISC CPU Coulomb Counter CCBAT CCPACK Current A /D Internal Oscillator LED Control 6 Reset Logic RSTN I/O Safety LED1-5, LEDEN SMBCLK SMBDAT SMBus Watchdog Measure FUSE CSBAT CSPACK 2 nd Level Safety Internal Temperature Core / CPU PRE CHG DSG EFCID st SRAM Voltage Balance Temp 2.5V LDO-2 CELL 4 V3 PUMP 3 XT 3 2.5V LDO-1 Voltage Balance Temp CELL 1 V4 PUMP 4 XT 4 CELL 2 bq6400 BLOCK DIAGRAM ALERT Pack Interface * XT1 & XT2 inputs can optionally multiplex up to five (5) additional temperature sensors each . AVAILABLE OPTIONS (1) (1) 2 PRODUCT PACKAGE PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE ORDERING NUMBER TRANSPORT MEDIA QUANTITY bq6400 QFN-48 7×7mm RGZ –40°C to 85°C bq6400RGZR Reel 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. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 XT4 V4 SMBDAT SMBCLK 40 39 38 37 V3 XT3 42 41 V2 VLDO2 44 43 XT1 XT2 46 45 VSS V1 48 47 QFN-48 PACKAGE CHG 1 36 LED 5 DSG 2 35 LED 4 PRE 3 34 LED 3 EFCIC 4 33 LED 2 EFCID 5 32 LED 1 CCBAT 6 31 LEDEN CCPACK 7 30 FUSE VLDO1 8 29 XC CSBAT 9 28 MISO/ALERT CSPACK 10 27 MOSI NC 11 26 SCLK NC 12 25 RSTN 24 23 P4N NC 21 22 P4S P3N 19 20 P3S SDI3 18 17 P2N 16 13 15 P1N P2S SDO2 * SDI1 49 B TA SDO0 14 bq6400 *Tab connection located bottom center , see mechanical drawing for detail . TERMINAL FUNCTIONS TERMINAL NO. (1) NAME I/O (1) DESCRIPTION 1 CHG O Charge MOSFET control (Active high, enables current flow.) 2 DSG O Discharge MOSFET Control (Active high. Low opens MOSFET.) 3 PRE O Pre-Charge MOSFET control (Active high.) 4 EFCIC I External Charge FET Control, Intel™ AMPS compatible input 5 EFCID I External Discharge FET Control, Intel™AMPS compatible input 6 CCBAT IA Coulomb counter input (sense resistor), connect to battery negative 7 CCPACK IA Coulomb counter input (sense resistor), connect to pack negative 8 VLDO1 P Internal LDO-1 output, bypass with capacitor 9 CSBAT IA Current sense input (safety), connect to battery negative 10 CSPACK IA Current sense input (safety), connect to pack negative 11 N/C – Do not connect to this pin 12 N/C – Do not connect to this pin 13 SDO0 O Requires 100kΩ pull-up resistor to VLDO1 14 SDI1 I Connect to SDO0 via a capacitor 15 P1N O Charge balance gate drive, cell 1 North 16 P2S O Charge balance gate drive, cell 2 South 17 P2N O Charge balance gate drive, cell 2 North 18 SDO2 O Connect to SDI3 via capacitor 19 SDI3 I Connect to SDO2 via capacitor 20 P3S O Charge balance gate drive, cell 3 South 21 P3N O Charge balance gate drive, cell 3 North 22 P4S O Charge balance gate drive, cell 4 South 23 P4N O Charge balance gate drive, cell 4 North 24 N/C – Do not connect to this pin 25 RSTN I Device reset, active low I – input, IA – analog input, O – output, OA – analog output, OD – open drain output, p – power Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 3 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com TERMINAL FUNCTIONS (continued) TERMINAL NO. 4 NAME I/O (1) DESCRIPTION 26 SCLK – Do not connect to this pin 27 MOSI I Do not connect to this pin 28 MISO/ALERT O Optional ALERT output – asserted low on alarm condition (interrupt) 29 XC O Aux control 30 FUSE O Safety fuse control output, active high 31 LEDEN O LED common anode drive (hi), Aux Temp(n) input enable (low) 32 LED1 IO SOCi LED drive (active low), Aux Temp input 33 LED2 IO SOCi LED drive (active low), Aux Temp input 34 LED3 IO SOCi LED drive (active low), Aux Temp input 35 LED4 IO SOCi LED drive (active low), Aux Temp input 36 LED5 IO SOCi LED drive (active low), Aux Temp input 37 SMBCLK IO SMBus clock signal 38 SMBDAT IO SMBus data signal 39 V4 IA Cell 4 positive input 40 XT4 IA External temperature sensor 4 input 41 XT3 IA External temperature sensor 3 input 42 V3 IA Cell 3 positive input 43 VLDO2 P Internal LDO-2 output, bypass with capacitor 44 V2 IA Cell 2 positive input 45 XT2 IA External temperature sensor 2 input / mux temp input 2 46 XT1 IA External temperature sensor 1 input / mux temp input 1 47 V1 IA Cell 1 positive input 48 VSS IA Cell 1 negative input TAB TAB P Connect to VSS Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range (unless otherwise noted) RANGE UNITS TA Operating free-air temperature (ambient) –40 to 85 °C TSTORAGE Storage temperature –65 to 150 °C V4-V3 Max cell voltage –0.5 to 5.0 V V3-V2 Max cell voltage –0.5 to 5.0 V V2-V1 Max cell voltage –0.5 to 5.0 V V1-VSS Max cell voltage –0.5 to 5.0 V Voltage on LED1-5 With respect to VSS 0.5 to 5.0 V V Voltage on CCBAT, CCPACK, CSBAT, CSPACK, XT1, XT2,SDIX, SDOX, LEDEN, FUSE Max voltage on any I/O pin (VSS – 0.5) to (VLDO1 + 0.5) Voltage on XT3, XT4 Maximum voltage range (V2 – 0.5) to (VLDO2 + 0.5) V EFCIC, EFCID With respect to VSS –0.5 to 5.5 V Voltage on SMBCLK, SMBDAT, ALERT With respect to VSS –0.5 to 6.0V V Voltage on PRE, CHG, DSG With respect to VSS –0.5 to (VLDO1 + 0.5) V Current through PRE, CHG, DSG, LEDEN, LED1-5 Maximum current source/sink 20 mA VLDO1 maximum current Maximum current draw from VLDO 20 mA ESD tolerance JEDEC, JESD22-A114 Human Body Model, R=1500 Ω, C=100 pF 2 kV Lead Temperature Soldering Total time < 3 seconds < 300 °C (1) Stresses or conditions in excess of those listed may cause permanent damage to the device. Exposure to these conditions for prolonged periods may adversely affect device reliability. These ratings are provided for reference only, and not meant to imply functional operation at these maxima or other circumstances beyond those indicated under recommended operating conditions. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 5 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com ELECTRICAL CHARACTERISTICS TA = –40°C to 85°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT DC CHARACTERISTICS VCELL (1) Operating range Cells balanced IDD Operating mode current Measure / report state 250 µA ISTBY Standby mode current SMBCLK = SMBDAT = L 150 µA ISHIP Ship mode current 40 µA IECUV (2) Extreme cell under voltage shutdown current VOL VOH VIL 2.3 All cells < 2.7 V and any cell < ECUV setpoint 1.0 IOL < 4.0 mA (3) General I/O pins 4.5 IOH < –4.0 mA 0 µA 0.5 VLDO1–0.10 VLDO1× 0.25 VIH V V VLDO1× 0.75 VOLTAGE MEASUREMENT CHARACTERISTICS Measurement range 2.500 4.500 V Resolution <1 mV Accuracy ±3 mV CURRENT SENSE CHARACTERISTICS Measurement range (4) –0.100 Input Offset Resolution Accuracy (5) COULOMB COUNTER CHARACTERISTICS (6) Resolution Default range 10 µV ±10 µV ±0.1% of reading µV 2.8 (8) nVh 0.008% ±30 (9) Snap-to-Zero (deadband) 6 V µV (7) Integral non-linearity (1) (2) (3) (4) (5) (6) (7) (8) (9) 0.100 ±50 µV Device remains operational to 1.85 V with reduced accuracy and performance. All cells at 2.3V at 25°C. Does not apply to SMBus pins Default range. Corresponds to ±10A using a 10mΩ sense resistor. Other gains and ranges available (8 options). After calibration. Accuracy is dependent on system calibration and temperature coefficient of sense resistor. Shares common inputs with Current Sense section. After calibration. Accuracy is dependent on system calibration and temperature coefficient of sense resistor. Corresponds to 0.0003mAh using 10mΩ sense resistor. Corresponds to 3mA using 10mΩ sense resistor. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 ELECTRICAL CHARACTERISTICS (Continued) TA = –40°C to 85°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 0.650 V CURRENT SENSE (SAFETY) CHARACTERISTICS (1) Measurement Range – Gain 1 –0.650 Resolution (short circuit detection) 20 Resolution (over-current detection, charge and discharge) 2.5 Measurement Range – Gain 2 –0.325 Resolution (Short circuit detection) Resolution (over-current detection, charge and discharge) mV mV 0.325 V 10 mV 1.25 mV INTERNAL TEMPERATURE SENSOR CHARACTERISTICS Measurement Range –30 Resolution Accuracy (after calibration) TA = –30°C to 85°C 85 °C 0.1 °C 1 °C EXTERNAL TEMPERATURE SENSOR(s) TYPICAL CHARACTERISTICS (2) Measurement Range (3) –40 Resolution Accuracy (4) 90 0.2 TA = 25°C ±1 TA = 0°C to 85°C ±2 °C °C °C SMBus CHARACTERISTICS (5) VIL Input low voltage VIH Input high voltage VOL (6) Output low voltage CI Capacitance each I/O pin FSCL SCLK nominal clock frequency RPU (7) Pull-up resistors for SCLK, SDATA (1) (2) (3) (4) (5) (6) (7) 350 µA sink current 0 0.8 V 2.1 5.5 V 0 0.4 V 10 pF TA = 25°C 100 kHz VBUS 5V nominal 13.3 15.3 VBUS 3V nominal 2.4 6.8 kΩ Post calibration: Dependent on calibration and temperature coefficient of sense resistor. Uncertainty 1.5 LSB. Typical for dual diode (MMBD4148 or equivalent) external sensor using recommended circuit. Range of diode sensors may exceed operational limits of IC and battery cells. Typical behavior after calibration, final result dependent on specific component characteristics. SMBus timing and signals meet the SMBus 2.0 specification requirements under normal operating conditions. All signals are measured with respect to PACK-Negative. Parameter not tested in production. Pull-ups are typically implemented external to battery pack, and are selected to meet SMBus requirements. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 7 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com RPRE CHEMICAL FUSE PRE C HG DS G + PACK + FUSE SDO2 SDI3 External Independent Safety CELL 1 LED1 V4 LED2 Cell Balancing Circuits CELL 4 CELL 3 CELL 2 LED3 V3 LED4 Battery Management Controller VLDO 2 V2 LED5 LEDEN SOCi EFCIC CNT1 SDI 1 EFCID CNT2 CRFI MOSI SDO 0 One of 12 external sensors shown MISO/ALERT VLDO1 SMBCLK Typical four cell configuration shown . Some components omitted for clarity . CSPACK CCBAT CSBAT VS S TAB RSTN CCPACK SMBDAT SMBCLK SMBDAT SMBus XT 1-4 ESD Protection Temperature Sensor (typical) AMPS V1 CELL 1 - PACK - RSENSE Figure 1. bq6400 Simplified Example Circuit Diagram FEATURE SET Primary (1st Level) Safety Features The bq6400 implements a breadth of system protection features which are easily configured by the customer. First Level protections work by controlling the MOSFET switches. These include: • Battery cell over/under voltage protection • Battery pack over/under voltage protection 8 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 • • • • • • • • • Charge and discharge over-current protection Short circuit protection Intel™ AMPS compatible external MOSFET control inputs One internal temperature sensor External MOSFET Control Inputs (EFCIx) with programmable polarity Up to twelve (12) external temperature inputs for accurate cell and MOSFET monitoring Watchdog timer protection Unconnected FUSE drive output Brownout detection and protection against extreme pack under voltage Secondary (2nd Level) Safety Features The bq6400 can detect more serious system faults and activate the FUSE pin, which can be used to open an in-line chemical fuse to permanently disable the pack. Secondary optional features include: • Fully independent of First Level protections • SmartSafety™ algorithms for early detection of potential faults – Temperature abnormalities (variances, rate of change, etc.) – Disconnected cell voltage inputs – Cell imbalance exceeds safety limit – Impedance rise due to cell or weld strap fault • MOSFET failure or loss of MOSFET control • Safety over-voltage, pack and cell • Safety over-temperature, limits for both charge and discharge • Safety over-current, charge and discharge • Failed current measurement, voltage measurement, or temperature measurement Charge Control Features • Meets SMBus 2.0 and Smart Battery System (SBS) Specification 1.1 requirements • Active cell balancing using patented PowerPump™ technology which eliminates unrecoverable capacity loss due to normal cell imbalance • Balancing-current tracked to detect cell problems • Simultaneous, synchronous measurement of all cell voltages in a pack • Simultaneous, synchronous measurement of pack current with cell voltages • Reports target charging current and/or voltage to an SBS Smart Charger • Reports the chemical State-of-Charge for each cell and pack • Supports precharging and zero-volt charging with separate FET control • Programmable, chemistry-specific parameters • Fault reporting Fuel Gauging • The bq6400 accurately reports battery cell and pack state-of-charge (SOC), with greater than 1% precision. No full charge/discharge cycle is required for accurate reporting. • State-Of-Charge is reported via SMBus and available via LED display. Data available in Amp-hours and Watt-hours. • 18-bit Integrating Delta-Sigma A/D Coulomb Counter, with programmable snap-to-zero value. LED Display • The bq6400 drives a three to five segment LED display in response to a push-button (LEDEN) input signal. Each LED pin can sink up to 10 mA. Lifetime Data Logging (readable via SMBus) • Recording of faults, events, anomalies, min and max values Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 9 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com • • • • Maximum/minimum cell temperature Maximum/minimum pack voltage Maximum/minimum cell voltages Maximum discharge power Forensic Data Logging (Readable via SMBus) • Last known full capacity of the battery • Capacity (or SOC) at the time of failure • Cycle count and/or cumulative number of Ah delivered by the battery • Battery pack status; being charged, discharged or at rest • Balancing effort required by each bank of cells to maintain balance • Cell bank impedance information • Last ten (10) previous failures causing primary (first level) safety action • Degree days histogram (time that the battery has spent in a temperature range) • Voltage Hours – Time for each cell measurement spent above/below safety limits • Forensic data up-loadable to Host CPU via SMBus (see below) • Forensic data recording of anomalies and events Power Modes • Normal Mode: The bq6400 performs measurements and calculations, makes decisions, and updates internal data at approximately once per second. All safety circuitry is fully functional in this mode. • Standby Mode: The bq6400 performs as in normal mode, but at a reduced measurement rate to lower power consumption at times when the host computer is inactive or the pack is removed from the system. All safety circuitry remains fully functional in this mode. • Ship Mode: The bq6400 disables (opens) all the protection MOSFETs, and continues to monitor temperature and voltage, but at a reduced measurement rate to dramatically lower power consumption. Environmental data is saved in flash as a part of the historical record. Safety circuitry is disabled in this mode. The device does not enter this power state as a part of normal operation – it is intended for use after factory programming and test. Entry occurs only after a unique SMBus command is issued and then only when the SMBus lines are set to logic low. Exit occurs when the SMBus lines return to an active state. • Extreme Cell Under-Voltage (ECUV) Shutdown Mode: In this mode, the bq6400 draws minimal current and the Charge and Discharge protection MOSFETs are disabled (opened). The Pre-Charge MOSFET remains enabled when a charge voltage is present. Safety circuitry is disabled in this mode. The device does not enter this mode as a part of normal operation: It enters this state during extreme cell under-voltage conditions (ECUV). The ECUV threshold is fully programmable below 2.7V. STATE CURRENT DRAW (TYP) OVER-CURRENT ENTRY CONDITION EXIT CONDITION Active < 250 µA Fully active Normal operation as determined by firmware Firmware directed to operating modes below Standby < 150 µA Fully active No load current flowing for predetermined time Load activity Ship < 40 µA Not active Protected SMBus command and SMBus then off (low) Either SMBus line high Extreme Cell Under-Voltage < 1 µA Not active (Pre-Charge enabled) Enabled when Vcell < ECUV Vcell charge above ECUV recovery threshold (2.7V/cell typical) OPERATION The bq6400 Battery Management Controller serves as the master controller for a Li-Ion battery system consisting of three or four cells in series. Any number may be connected in parallel; other system or safety issues will limit this to a more practical number. The bq6400 provides extraordinarily precise State-of-Charge gas gauging, and first and second level pack safety functions. Voltage and current measurements are performed synchronously and simultaneously for all cells in the pack allowing a level of precision not previously possible in battery 10 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 management. Temperature is measured by one internal sensor and up to 12 additional multiplexed external temperature sensors, for a total of up to 13 independent measurement points in the pack. Coulomb counting is captured continuously by a dedicated 18-bit integrating Delta-Sigma A/D converter. The bq6400 is also responsible for pack data calculations, black-box forensic data storage and communicating parameters via SMBus to a host processor as the core of a Smart Battery System (SBS). Safety Unique in the battery management controller market, the bq6400 simultaneously measures voltage and current using independent and highly accurate Delta-Sigma A/D converters. This technique removes virtually all systemic noise from measurements, which are made during all modes of battery operation – charge, discharge, and rest. Battery impedance and self-discharge characteristics are thus measured with an unprecedented level of accuracy in real-time. The device applies this precise information to SmartSafety™ algorithms to detect certain anomalies and conditions which may be indicative of internal cell faults, before they become serious problems. The bq6400 uses its enhanced measurement system to detect pack faults including cell under and over-voltage, cell under and over-temperature, pack over-voltage, and pack over-current, over-charge, and short circuit conditions. First level safety algorithms will first attempt to open the MOSFET safety switches. If this fails, 2nd level safety algorithms will open the in-line chemical fuse and provide permanent, hard protection for the pack and user. External MOSFET control inputs with programmable polarity can also be used to operate the protection MOSFETs under control of user supplied circuitry. The bq6400 continuously monitors these inputs. If the MOSFETs fail to open when commanded, the 2nd level safety algorithms will also activate the fuse. All 1st and 2nd level safety algorithms have programmable time delays to prevent false triggering on noise events. Cell Balancing Patented PowerPump™ cell balancing drastically increases the useful life of battery packs by eliminating the cycle life fade of multi-cell packs due to cell imbalance. PowerPump™ efficiently transfers charge from cell to cell, rather than simply bleeding off charging energy as heat the way competitor’s circuits using resistive-bleed balancing do. Balancing is configurable and may be performed during any combination of battery operational modes – charge, discharge, and rest. Compared to resistive bleed balancing, virtually no energy is lost as heat. The actual balance current is externally scalable and can range from 10mA to 1A depending on component selection and application or cell requirements. A variety of techniques, such as voltage or State-Of-Charge balancing, are easily implemented by the bq6400. By tracking the balancing required by individual cells, overall battery safety is enhanced – often allowing early detection of soft shorts or other cell failures. Balancing is achieved between all cells within the pack as dynamically determined by the bq6400. Outputs Charge Control The open drain outputs CHG and PRE are used to drive MOSFET transistors controlling cell stack charging. Charge or Pre-charge mode is selected based on the current cell voltage compared to the user-definable cell pre-charge under-voltage thresholds. When below the limit, or when below the charge temperature minimum, the PRE signal is active and CHG signal is inactive. This turns on the Pre-Charge MOSFET and is used to charge a depleted pack through a current-limiting series resistor. When all cell voltages are above the limit and the temperature is above the charge temperature minimum, then the CHG output also becomes active and enables the Charge MOSFET to turn on and provide a high current path between the charger and battery cells. The CHG and PRE MOSFET control outputs are both disabled (low) when a cell reaches any safety cutoff limit or temperature threshold. During active charging modes (and above cell voltage thresholds), the Discharge MOSFET is also enabled to avoid excessive heating of the body diode. Similarly, the CHG MOSFET is active during discharge provided current flow is in the correct direction and no safety violations are present. The CHG and PRE outputs are intended to drive buffer transistors acting as inverting level shifters. Discharge Control The DSG output operates similarly to control cell stack discharging. It is enabled (high) by default. If either a cell voltage falls below the lower threshold, or excessive current or other safety related fault is sensed, the DSG output is disabled (low) to prevent damage to the cell or pack. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 11 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com All facets of safely charging and discharging the cell stack are controlled by user-definable parameters which provide precise control over MOSFET states. Both pack and cell over and under-voltage limits are provided as well as programmable hysteresis to prevent oscillation. Temperature and current thresholds are also provided, each with independent timers to prevent nuisance activations. LEDEN This pin is multi-purpose: It can provide output current to the LED display array; it can be used as an output to enable multiplexing of eleven external temperature sensors; or it can be a State-of-Charge indicator (SOCi) push-button input. (This pin can also be configured as a general purpose I/O pin.) LED SOCi Outputs LED1-5 are current sinking outputs designed to drive low-current LEDs. The LEDs can be activated by the LEDEN pin via a pushbutton switch. They can be configured (using SBS parameters) to operate in bar or dot mode and to use 3-5 LEDs to represent State-Of-Charge information. Inputs Current Measurement Current is monitored by four (4) separate A/D converters. All utilize the same very low value sense resistor, typically either 5 or 10 milliohms in series with the pack negative connection. CCBAT and CCPACK connections to the sense resistor utilize an R/C filter for noise reduction. (CSBAT and CSPACK are direct connections used for secondary safety.) A 14-bit Delta-Sigma A/D converter is used to accurately measure current flow in both directions. The measurements are taken simultaneously and synchronously with the cell voltage measurements. This value is used for internal calculations, and SMBus reporting. Coulomb Counting A dedicated Coulomb counter is used to measure charge flow with 18 bit precision in both directions by a calibrated, integrating Delta-Sigma A/D converter. This allows the bq6400 to keep very accurate State-Of-Charge (SOC) information and battery statistics. A small deadband is applied to further reduce noise effects. The Coulomb counter is unique in that it continues to accumulate (integrate) current flow in either direction even as the rest of the internal microcontroller is placed in a very low power state, further lowering power consumption without compromising system accuracy. Safety Current Two additional A/D converters are used to directly monitor for over current or short-circuit current conditions, independently of the internal microcontroller. This provides a direct and rapid response to insure pack integrity and safe operation. Voltage Measurement Voltage measurement is performed by four independent Delta-Sigma A/D converters which operate simultaneously and are triggered synchronously so that all four voltages are read at precisely the same moment. Voltage is converted with better than 1mV of resolution providing superior accuracy. One A/D per-cell technology means that voltage is also measured simultaneously with current, permitting accurate, real-time cell impedance calculation during all operating conditions. This technique also provides greatly enhanced noise immunity and filtering of the input voltages without signal loss. Temperature Measurement Temperature measurement is performed by up to twelve (12) external low cost sensor diodes, and one internal silicon sensor. Each external sensor consists of a low cost silicon diode and capacitor combination. These may be used to monitor individual cell conditions, sense resistor or MOSFET temperatures, or other sources determined by the user. The bq6400 can report all of these temperatures individually, and as an average. XT1-2 can be used as dedicated inputs, or they can be used as multiplexed inputs providing ten (10) external temperature sensors to the pack designer. In this configuration, the cathodes of five (5) of the sensors are connected to the cathodes of the LED1-5 connections. The anodes are connected together and then to XT1. The bq6400 internally multiplexes the LEDEN, LED and XT1 pins to read the temperature sensors using this scheme. Similarly, another five (5) sensors can be connected together and read via the XT2 input. XT3-4 are dedicated inputs directly connected to the external temperature sensors, providing the eleventh and twelfth external inputs. 12 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 bq6400 www.ti.com ......................................................................................................................................................................................... SLUS841 – SEPTEMBER 2008 EFCIx The External FET Control Inputs are for user control of MOSFETs based on external circuitry and conditions. The polarity of the input signal is user programmable. Two modes of operation are possible: The first mode is used to implement additional hardware safety inputs, and is used to force the MOSFETs to an OFF state. The inputs control the MOSFETs directly through hardware, no firmware is used. The second mode of operation is used to implement the Intel™ AMPS interface signals CNT1 and CNT2 without additional circuitry. COMMUNICATIONS SMBus The bq6400 uses the industry standard Smart Battery System’s two-wire System Management Bus (SMBus) communications protocol for all external communication. SMBus version 2.0 is supported by the bq6400, and includes clock stretching, bus fault timeout detection, and optional Packet Error Checking (PEC). For additional information, see the www.smbus.org or www.sbs-forum.org websites. Smart Battery Data (SBData) The data content and formatting of the bq6400 information conforms to the Smart Battery System’s (SBS) Smart Battery Data specification, version 1.1. The reader is directed to the SBS/SMBus site at www.sbs-forum.com for further information regarding these specifications. This SBS Data (SBData) specification defines read/write commands for accessing data commonly required in laptop computer applications. The commands are generic enough to be useful in most applications. The bq6400 provides a wealth of control and battery information beyond the SBData standard. For the additional data, new command codes have been defined. In addition, new battery data features, such as State-of-Health, use newly defined extended SBData command codes are used. SBS Standard Data Parameter List (abridged) 1. 2. 3. 4. Parameters 0x00 – 0x3F are compatible with the SBDATA specification. Parameters 0x40 – 0x7F are reserved for compatibility with other manufacturer’s assignments Parameters 0x80 – 0xFF are specific for internal use. By default, the bq6400 initially responds to the SBData slave address <0001 011R/W> (0x16, 0x17). COMMAND DATA TYPE DESCRIPTION 00 R/W Word (unsigned) Manufacturer Access 01 R/W Word (unsigned) Remaining Capacity Alarm Level 02 R/W Word (unsigned) Remaining Time Alarm Level 03 R/W Word (unsigned) Battery Mode 04 R/W Word (unsigned) At Rate value used in AtRate calculations 05 Read Word (unsigned) At Rate Time to Full 06 Read Word (unsigned) At Rate Time to Empty 07 Read Word (Boolean) At Rate OK 08 Read Word (unsigned) Pack Temperature (maximum of all individual cells) 09 Read Word (unsigned) Pack Voltage (sum of individual cell readings) 0A Read Word (unsigned) Pack Current 0B Read Word (unsigned) Average Pack Current 0C Read Word (unsigned) Max Error 0D Read Word (unsigned) Relative State of Charge 0E Read Word (unsigned) Absolute State of Charge 0F Read Word (unsigned) Remaining Pack Capacity 10 Read Word (unsigned) Full Charge Capacity 11 Read Word (unsigned) Run Time to Empty 12 Read Word (unsigned) Average Time to Empty 13 Read Word (unsigned) Average Time to Full Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 13 bq6400 SLUS841 – SEPTEMBER 2008 ......................................................................................................................................................................................... www.ti.com COMMAND DESCRIPTION 14 Read Word (unsigned) Charging Current 15 Read Word (unsigned) Charging Voltage 16 Read Word (unsigned) Battery Status 17 Read Word (unsigned) Cycle Count 18 Read Word (unsigned) Design Capacity 19 Read Word (unsigned) Design Voltage 1A Read Word (unsigned) Specification Information 1B Read Word (unsigned) Manufacture Date 1C Read Word (unsigned) Serial Number 1D-1F 14 DATA TYPE Reserved 20 Read Block (String) Pack Manufacturer Name (31 characters maximum) 21 Read Block (String) Pack Device Name (31 characters maximum) 22 Read Block (String) Pack Chemistry 23 Read Block (String) Manufacturer Data 24-2E Reserved 2F R/W Block 30-3B Reserved Optional Manufacturer Function 5 3C R/W Word (unsigned) Optional Manufacturer Function 4 (Vcell 4) 3D R/W Word (unsigned) Optional Manufacturer Function 3 (Vcell 3) 3E R/W Word (unsigned) Optional Manufacturer Function 2 (Vcell 2) 3F R/W Word (unsigned) Optional Manufacturer Function 1 (Vcell 1) 40-45 <unused> 46-47 Reserved 48-4F <unused> 50-55 Reserved 56-57 <unused> 58-5A Reserved 5B-5F <unused> 60-62 Reserved 63-6F <unused> 70 Reserved 71-FF <unused> Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s) :bq6400 PACKAGE OPTION ADDENDUM www.ti.com 25-Sep-2008 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty BQ6400RGZR ACTIVE QFN RGZ 48 2500 TBD Call TI Call TI BQ6400RGZT ACTIVE QFN RGZ 48 250 TBD Call TI Call TI Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 IMPORTANT NOTICE 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 Amplifiers Data Converters DSP Clocks and Timers Interface Logic Power Mgmt Microcontrollers RFID RF/IF and ZigBee® Solutions amplifier.ti.com dataconverter.ti.com dsp.ti.com www.ti.com/clocks interface.ti.com logic.ti.com power.ti.com microcontroller.ti.com www.ti-rfid.com www.ti.com/lprf Applications Audio Automotive Broadband Digital Control Medical Military Optical Networking Security Telephony Video & Imaging Wireless www.ti.com/audio www.ti.com/automotive www.ti.com/broadband www.ti.com/digitalcontrol www.ti.com/medical www.ti.com/military www.ti.com/opticalnetwork www.ti.com/security www.ti.com/telephony www.ti.com/video www.ti.com/wireless Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2008, Texas Instruments Incorporated