Fuel Gauge---MAX17260

0 Preface/Foreword

0.1 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（Maxim）

1 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.

1. ampere: 安培
2. coulomb：库伦（电量单位）
3. 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, smartwatches
• Tablets,2-in-1Laptops. (二合一笔记本电脑)
• Bluetooth headsets
• Health and fitness monitors
• Digital Still, Video, and Action Cameras
• Medical Devices
• Handheldcomputers and terminals. (手持)
• Wireless Speakers
• Home and Building Automation, Sensors
• Portable Game Players
• Toys

1.3 Benefits and Features

• ModelGauge m5 EZ
  • Nocharacterizationrequried 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 states
• Low 5.1uA operating current
• Accuratecurrent sensing
  • High-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 required
• Alert indicatorfor voltage, SOC, temperature, current, and 1% SOC change.

1.4 Simple Fuel-Gauge Circuit diagram

1.5 Absolute Maximum Ratings

• operating temperature range
• junctiontemperature: 结温
• storage temperature
• soldering temperature (reflow)

1.5.1 Junction temperature

Junction 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：ambienttemperature，Ta
• 不是PCB温度
• 不是芯片外壳温度，CaseTemperature，Tc
• 而是芯片内部最热点的位置温度。
• 通常是Tj > Tc > Ta。

1.6 Electrical Characteristics

• Power supply
  • supply voltage
  • shutdown supply currrent
  • hiberante supply current
  • active supply current
  • regulation voltage
  • startup voltage
• Analog-to-digital converntion
  • BATT measurement error：7.5 mV
  • BATT measurement resolution：78.125uV
  • BATT measurement range：2.3 - 4.9 V
• Input/output
  • External thermistance resistance
  • battery-detachdetection threshold.
  • battery-detach detction thresholdhysteresis(迟滞；滞后；磁滞)

1.7 PIN configuration

1.8 Functional Diagram

Detailed 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 Intel's 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 performance

• ModelGauge 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 algorithm

• Classical 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 information

1.10 typical application circuits

1.11 layout guidelines

1.12 Register memory map

1.12.1 Model-Gauge m5 related

1.12.2 serial number format

1.12.3 ModelGauge m5 EZ configuration registers

• The 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 - DesignCap
  • Empty Voltage - VEmpty
  • Charge Termination Current - ICHGTerm

2 项目应用

2.1 原理图设计