• [ CXLB73297 ]"

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Introduction

In today's rapidly developing portable electronic devices, dual cell series lithium batteries are widely used in various consumer electronics products due to their higher voltage and energy density. CXLB73297, as an efficient boost charging management chip designed specifically for dual cell lithium batteries, has become an ideal choice for engineers to develop compact charging solutions due to its high integration, excellent thermal performance, and simple peripheral circuits. This article will provide an in-depth analysis of the technical features, application design, and selection points of CXLB73297, in order to assist in the rapid launch of the product. uM1嘉泰姆

1. CXLB73297 chip overview

        CXLB73297 It is a synchronous boost charging management chip designed specifically for dual cell series connected lithium-ion/polymer batteries. Adopting SOP8 packaging, integrating power MOSFET and synchronous switch architecture, greatly simplifies peripheral circuit design and significantly reduces BOM costs. uM1嘉泰姆

The main features of this chip include:uM1嘉泰姆

·    Input voltage range: 4.5V-5.5VuM1嘉泰姆

·    Constant voltage charging voltage: 84VuM1嘉泰姆

·   恒流充电电流：0.5AuM1嘉泰姆

·   开关频率：400KHzuM1嘉泰姆

·   转换效率高达93%uM1嘉泰姆

CXLB73297支持完整的消流/恒流/恒压充电模式，能够智能管理充电全过程，确保电池安全且充满。uM1嘉泰姆

二、核心特性与优势

2.1.  高效率性能uM1嘉泰姆

·   同步升压架构，5V输入8V/0.5A输出时效率达93%uM1嘉泰姆

·   400KHz开关频率，支持使用2.2μH小尺寸电感uM1嘉泰姆

2.2.Intelligent Charging ManagementuM1嘉泰姆

·    Current dissipation charging: When the battery voltage is less than 6V, charge with a small current of 75mAuM1嘉泰姆

·    Constant current charging: When the battery voltage is greater than 6V, fast charging with a constant current of 0.5AuM1嘉泰姆

·    Constant voltage charging: When approaching 8.4V, switch to constant voltage mode to ensure that the battery is fully chargeduM1嘉泰姆

2.3. Comprehensive protection mechanismuM1嘉泰姆

·    Input undervoltage protection: threshold 4.5V to prevent adapter overloaduM1嘉泰姆

·    Input overvoltage protection: threshold 6.0V, hysteresis 400mVuM1嘉泰姆

·   IC Over temperature protection: turn off at 135 ℃, restore at 110 ℃uM1嘉泰姆

·    Output overvoltage protection to ensure system safetyuM1嘉泰姆

2.4.Concise peripheral designuM1嘉泰姆

·    Only a small amount of capacitors, inductors, and LED indicator lights are neededuM1嘉泰姆

·   SOP8 Encapsulation, occupying a small PCB areauM1嘉泰姆

·    Integrated power MOS, no need for external discrete devicesuM1嘉泰姆

III. Typical Application Scenarios

CXLB73297 is very suitable for the following applications:uM1嘉泰姆

·    Portable medical devices: thermometers, blood pressure monitors, etcuM1嘉泰姆

·    Handheld instruments and meters: multimeter, rangefinderuM1嘉泰姆

·    Consumer electronics products: Bluetooth speakers, portable lighting fixturesuM1嘉泰姆

·    Industrial control equipment: handheld terminals, data collectorsuM1嘉泰姆

Its compact design and efficient performance make it particularly outstanding in space constrained applications.uM1嘉泰姆

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四、详细充电过程解析

CXLB73297采用智能三阶段充电算法：uM1嘉泰姆

4.1. 消流充电阶段uM1嘉泰姆

·   当电池电压低于6V时，芯片以75mA消流电流充电uM1嘉泰姆

·   有效恢复深度放电电池，避免大电流冲击uM1嘉泰姆

4.2.  恒流充电阶段uM1嘉泰姆

·   电池电压超过6V后，进入0.5A恒流充电uM1嘉泰姆

·   快速为电池补充能量，缩短充电时间uM1嘉泰姆

4.3.  恒压充电阶段uM1嘉泰姆

·   当电池电压接近8.At 4V, switch to constant voltage modeuM1嘉泰姆

·    The charging current gradually decreases until it is fully chargeduM1嘉泰姆

·    Cut off current 50mA to prevent overcharginguM1嘉泰姆

4.4. Automatic Recharge Function: After the battery is fully charged, if the voltage drops back to 8.2V, the chip automatically restarts the charging cycle to ensure that the battery always maintains its optimal state. uM1嘉泰姆

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V. Circuit Design Guidelines

5.1. Key component selection

·    Power inductance: 2.2 μ H, saturation current>1A, DCR<20m ΩuM1嘉泰姆

·    Input capacitor: 10 μ F/25V ceramic capacitor, near VIN pinuM1嘉泰姆

·   VSYS Capacitor: 10 μ F/25V ceramic capacitor, close to VSYS pinuM1嘉泰姆

·    Bootstrap capacitor: 01μF/25V， Connect BST and LX pinsuM1嘉泰姆

5.2. LED status indication

·    Charging in progress: LED constantly onuM1嘉泰姆

·    Full: LED offuM1嘉泰姆

·    Abnormal state: LED flashing (including input overvoltage, chip overheating, battery not connected)uM1嘉泰姆

5.3. Battery detection function

The chip is equipped with intelligent battery detection. When the battery is not connected, the LED flashes to indicate, and after connecting the battery, it automatically enters the normal charging process. uM1嘉泰姆

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VI. Important Suggestions for PCB Layout

Correct PCB layout is crucial for system performance:uM1嘉泰姆

6.1.  VSYS电容布局uM1嘉泰姆

·   10μF电容必须紧靠VSYS引脚（第1脚）和GND引脚（第7脚）uM1嘉泰姆

·   电容地端与芯片地端直接连接，不能分隔uM1嘉泰姆

6.2.  VIN电容布局uM1嘉泰姆

·   10μF输入电容靠近VIN引脚（第5脚）和GND引脚uM1嘉泰姆

·   确保输入电源稳定性，减少纹波干扰uM1嘉泰姆

6.3.  功率路径设计uM1嘉泰姆

·   LX节点连接电感，走线应短而粗uM1嘉泰姆

·   GND引脚连接大面积铜皮，增强散热uM1嘉泰姆

6.4.Signal isolationuM1嘉泰姆

·   LED Control line should be kept away from LX switch nodeuM1嘉泰姆

·    Test pin (TEST) directly grounded
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7. Typical Application Bill of Materials (BOM)

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基于典型应用原理图，主要元器件包括：uM1嘉泰姆

7.1.  IC：CXLB73297 ×1uM1嘉泰姆

7.2.  电感：2.2μH ×1（饱和电流>1A）uM1嘉泰姆

7.3.  电容：10μF ×2，1μF ×1，0.1μF ×1uM1嘉泰姆

7.4.  LED：0603封装 ×1uM1嘉泰姆

7.5.  限流电阻：1K ×1uM1嘉泰姆
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八、技术支持与供货信息

JTM-IC（jtm-ic.com）作为CXLB73297的官方授权供应商，提供全方位技术支持：uM1嘉泰姆

8.1.   样品申请与批量供货服务uM1嘉泰姆

8.2.Reference Design and PCB ReviewuM1嘉泰姆

8.3. Professional technical Q&A and customized solutionsuM1嘉泰姆

8.4. Complete design documentation and data manualuM1嘉泰姆

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9. Packaging and Pin Functions

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Ten, Conclusion

       CXLB73297 With its high integration, excellent performance, and simple design, it has become an ideal choice for dual cell lithium battery charging applications. Whether in medical equipment, industrial instruments, or consumer electronics, its stable and reliable performance can add value to end products. Welcome touM1嘉泰姆

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