Fuel Gauge---MAX17260

0 Preface/Foreword0.1 公司介绍ANALOG DEVICES: 混合信号和数字信号处理IC | Analog Devices中文名亚德诺 (ADI)收购公司美信集成Maxim1 MAX17260介绍1.1 General information/description (概述一般说明)The MAX17260 is anultra-low powerfuel gauge ICwhich implements the Maxim ModelGauge m5 algorithm. The ICmonitorsa single-cell battery packand supports both high-side and low-sidecurrent sensing.ampere: 安培coulomb库伦电量单位odometer记程仪里程表Thisalgorithmmakes fuel gauge implementation easy byelimiatingbatterycharacterizationrequirements and simplifying host software interaction. The algorithm providestolerance againstbattery diversity for most lithium batteries and applications. The algorithm combines the short-term accuracy andlinearityof acoulomb counter(库仑计) with the long-term stability of a voltage-based fuel gauge, along with temperature compensation to provideindustry-leadingfuel gauge accuracy. The IC automaticallycompensatesforcell-aging(电芯老化),temperature,discharge rate, and providesaccurate state-of-charge(SOC)in percentageandremaining capacity(剩余容量) inmilliampere-hours(mAh) over a wide range of operating conditions. As the battery approaches the critical region near empty, the algorithm invokes a special correction mechanism that eliminates any error. The IC providesaccurate estimation(精确评估)oftime-to-empty(放空时间) andtime-to-full(充满时间) and provides three methods for reporting theage of the battery:reduction in capacity, increase in batteryresistance(电池阻抗), and cycleodometer(记程仪里程表).1.2 Applications相关应用如下所示Wearables, smartwatchesTablets,2-in-1Laptops. (二合一笔记本电脑)Bluetooth headsetsHealth and fitness monitorsDigital Still, Video, and Action CamerasMedical DevicesHandheldcomputers and terminals. (手持)Wireless SpeakersHome and Building Automation, SensorsPortable Game PlayersToys1.3 Benefits and FeaturesModelGauge m5 EZNocharacterizationrequried for EZ performance. (特征化)Robust againstbattery variation. 对xxxx具有鲁棒性Eliminates Error Near Empty Voltage.EliminatesCoulomb-Counter Drift.(库伦计数漂移)Compensatesfor age, current, and temperature.Dose not require empty, full, or idle statesLow 5.1uA operating currentAccuratecurrent sensingHigh-sideor low-side sensing option (高侧或低侧)Wide senseresistor range: 1m ohm to 1000m ohm.Trace sensingwith temperature compensation.Supports Li and variants including LiFePO4.Thermistoror internal temperature. (热敏电阻)Dynamic power estimatespower capabilityduring discharge.Time-to-empty and time-to-full estimation,predictremaining capacityundertheoretical load. (理论载荷)No calibration requiredAlert indicatorfor voltage, SOC, temperature, current, and 1% SOC change.1.4 Simple Fuel-Gauge Circuit diagram1.5 Absolute Maximum Ratingsoperating temperature rangejunctiontemperature: 结温storage temperaturesoldering temperature (reflow)1.5.1 Junction temperatureJunction temperature:简称Tj中文一般称为芯片结温或PN结温度。它表示的是芯片内部实际工作的半导体结 晶体管、MOSFET、二极管所在位置的温度。注意不是环境温度ambienttemperatureTa不是PCB温度不是芯片外壳温度CaseTemperatureTc而是芯片内部最热点的位置温度。通常是Tj Tc Ta。1.6 Electrical CharacteristicsPower supplysupply voltageshutdown supply currrenthiberante supply currentactive supply currentregulation voltagestartup voltageAnalog-to-digital converntionBATT measurement error7.5 mVBATT measurement resolution78.125uVBATT measurement range2.3 - 4.9 VInput/outputExternal thermistance resistancebattery-detachdetection threshold.battery-detach detction thresholdhysteresis(迟滞滞后磁滞)1.7 PIN configurationTDFN PINWLP PINNAMEFUNCTION2,3,4,5-NCNo Connection1A1THThermistor Input, Connect a thermistor from TH to GND. TH also provides battery insertion/removal detection. Connect to BATT if no used.14A2SCLSerial clock input. 2-wire clock line. Input only, SCL has an internal pulldown for sensing disconnection.13C1SDASerial data input/output. 2-wire data line. open-drain output driver. SDA has an internal pulldown for sensing disconnection.7A3CSNsense resistor negative sense point. on start up, the CSN voltage is measured to determine whether it is a high-side or low-side application. For a low-side application, Kelvin connect to the system side of the sense resistor; for ahigh-sideapplication, Kelvin connect to the cell side of thesense resistor.10C2CSPHHigh-side sense resistor positive sense point. for a high-side current sensing application, Kelvin connect to thesystem sideof an external high-side sense resistor. For a low-side current sensing application, tie to the BATT PIN.9-CSPLLow-side sense resitor postitive sense point. Kelvin connect to the cell side of the sense resistor.6B1BATTIC power supply andbattery voltagesense input. Connect to the positive terminal of a battery cell.Bypasswith a 0.1uF capacitor to GND.-C3GND/CSPLIC Ground and low-side sense resistor positive point. Kelvin connect to the cell side of the the sense resistor.8-GNDIC Ground11B3REGInternal 1.8Vregulatoroutput,bypasswith an external 0.47uF capacitor to GND. Do not load externally.12B2ALRTAlert output. The Alert pin is anopen-drainactive-lowoutput which indicates fuel-gauge alerts. Connect to GND if not used.1.8 Functional DiagramDetailed description:The max 17260 is an ultra-low power fuel gauge IC which implements theMaxim ModelGauge m5 EZalgorithm. The IC measure voltage, current, temperature accurately to produce fuel gauge results. The ModelGauge m5 EZ robust algorithm provides toleranceagainstbattery diversity. This additonal robustness enables simpler implementation for most applications and batteries by avoiding time-consuming battery characterization.The ModeGauge m5 algorithm combines theshort-termaccuracy and linearity of a coulomb-counter with thelong-termstability of avoltage-basedfuel gauge, along with termperature compensation to provideindustry-leadingfuel gauge accuracy. The IC automatically compensates for aging, temperature, and dischage rate and provides accurate state of charge (SOC) in percentage (%) andremaining capacityin milliampere-hours (mAhr) over a wide range of operating conditions. Fuel gauge error always converges to 0% as the cell approaches empty.The IC has a register set that is compatible with Intels DBPT v2 dynamic power standard. Thisallowsthe system designer to safely estimate the maximum allowed CPUturbo-boost(涡轮增压)powe level in complex power conditions. The IC provides accurate estimation of time-to-empty and time-to-full and provides three methods for reporting theage of battery:reduction in capacity,increase in battery resistance, andcycle odometer.The IC contains a unique serial number.Communication to the hostoccursover standardI2C interface.1.8.1 ModelGauge m5 EZ performanceModelGauge m5 EZperformance providesplug-and-playoperation when the IC is connnected to mostlithum batteries. While the IC can be custom tuned to the application specific battery through acharacterization processfor ideal performance, the IC has the ability to provide good performance for most applicationswith no custom characterization required.The ModelGauge m5 EZ provides good performance for most cell types. For some chemistries, such aslithium-iron-phosphate(LiFePO4) and panasonic NCR/NCA series ceells, it is suggested that the customer request a custom model from Analog Devices for best performance.For even better fuel-gauging accuracy than ModelGauge m5 EZ, contact Analog Devices for information regarding cell characterization.1.8.2 ModelGauge m5 algorithmClassical coulomb-counter-based fuel gauge have excellent linearity and short-term performance. However, they suffer from drift due to the accumulation of the offset error in the current-sense measurement. Although the offset error is often very small, it cannot be eliminated. it causes the reported capabity error to increase over time and requires periodic corrections. Corrections are traditionally performed at full or empty. Some other systems also use the relaxed battery voltage to perform corrections. These systemes determine the true state-of-charge (SOC) based on the battery voltage after a long time of no current low. Both have the same limitaion: if the correction condition is not observed over time in the actual application, the error in the system is boundless. The performance of classic coulomb counters is dominated by the accuracy of such corrections. Voltage measurement based SOC estimation has accuracy limitations due to imperfect cell modeling, but does not accumulate offset errorover time. (随着时间的推移)The IC includes an advanced voltage fuel gauge (VFG) that estimates open-circuit voltage (OCV), even during current flow, and simulates the nonlinear internal dynamics of a LI battery to determine the SOC with improved accuracy. The model considers the time effects of a battery caused by the chemical reactions and impedance in the battery to determine SOC. This SOC estimate does not accumulate offset error over time. The IC performs a smart empty compensation algorithm that automatically compensates for the effect of temperature conition and load condition to provide accurate state of charge information. The converge-to-empty function eliminates error toward empty state. The IC learns battery capacity over time automatically to improve long-term performance. The age information of battery is available in the output regsiters.The ModelGauge m5 algorithm combines a high-accuracy coulomb counter with a VFG. The complementary combined result eliminates the weakness of both the coulomb counter and the VFG while providing the strengths of both. A mixing algorithm weights and combines the VFG capacity with the coulomb counter and weighs each result so that both are usedoptimallyto determine the battery state. In this way, the VFG capacity result is used to continueouly make small adjustments to the battery state, cancelling the coulomb-counter drift. (最佳地)The ModelGauge m5 algorithm uses this battery state information andaccounts fortemperature, battery current, age, and application parameters to determine the remaining capacity to the system. A the battery approaches the critical region near empty, the ModelGauge m5 alrogorithm invokes a special error correction mechanism that eliminates any error.The ModelGauge m5 algorithm continually adapts to the cell and application through independent learning routines. As the cell ages, its change in capacity is monitored and updated and the voltage-fuel-gaugedynamicsadapt based on cell-voltage behavior in the application.1.9 ordering information1.10 typical application circuits1.11 layout guidelines1.12 Register memory map1.12.1 Model-Gauge m5 related1.12.2 serial number format1.12.3 ModelGauge m5 EZ configuration registersThe following registers are inputs to the ModelGauge m5 algorithm and store characerization information for the application cells as well as important application specific parameters.They are described briefly here.Only the following informationis requiredfor configuring ModelGauge m5 EZ:Label capacity - DesignCapEmpty Voltage - VEmptyCharge Termination Current - ICHGTerm2 项目应用2.1 原理图设计