CXLB73290E is a high-precision dual-cell lithium battery charging management chip that supports 5V USB adapter input. Its built-in complete charging cycle management functions, including 0V charging, current elimination charging, constant current charging, constant voltage charging and automatic cut-off and recharge mechanism. The chip is packaged in ESOP8, with a heat sink at the bottom, and external components are streamlined, greatly reducing system cost and design complexity.
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[ CXLB73290 ]"
CXLB73290E: High-efficiency dual-section lithium battery charging management chip detailed explanation and application guide
With the popularity of portable electronic devices, efficient and safe battery charging management has become a key link in product design. As a charging management chip designed for dual-cell lithium-ion batteries, CXLB73290E has become the first choice of engineers and manufacturers for its high integration, multiple protection functions and a wide range of application scenarios. This article will analyze the characteristics, working principle, design points and common problems of the CXLB73290E in depth to help readers fully grasp the application of this high-performance chip.
1. Product Overview: Why CXLB73290E?
CXLB73290E is a high-precision dual-cell lithium battery charging management chip that supports 5V USB adapter input. Its built-in complete charging cycle management functions, including 0V charging, current elimination charging, constant current charging, constant voltage charging and automatic cut-off and recharge mechanism. The chip is packaged in ESOP8, with a heat sink at the bottom, and external components are streamlined, greatly reducing system cost and design complexity.
The chip is suitable for a variety of portable devices, such as Bluetooth speakers, electronic cigarettes, walkie-talkies and adult products, compatible with USB or 5V adapter input, with 9V surge resistance, to ensure the application of high reliability and safety.
2. core features: the perfect combination of performance and protection
CXLB73290E set a number of advanced features in one, the following are its outstanding features:
· Efficient charging performance: Supports 10W and 2A input asynchronous switching boost charging, with an efficiency of up to 90%, a switching frequency of 600kHz, and can be matched with 2.2μH inductance to optimize system response.
· Intelligent current regulation: Built-in adaptive loop, automatically match all kinds of adapters, prevent input voltage drop, improve compatibility.
• Comprehensive protection mechanismsIncludes input undervoltage/overvoltage protection, output overvoltage/short circuit protection, IC over-temperature protection and ESD 4KV electrostatic protection to ensure chip and battery safety.
· Status indication and low power consumption: The LED indicator is driven by the STAT pin to display the charging status in real time; when the input is removed, the battery leakage current is less than 1μA, which has a significant energy saving effect.
3. Application Scenario: Widely Adapted to Portable Devices
The efficiency and reliability of the CXLB73290E make it shine in many fields:
· bluetooth speaker: Provide a stable and fast charging experience and extend the playing time.
· Electronic Cigarettes: Ensure battery safety and support frequent charge and discharge cycles.
· WALKIE TALKIE: Adapt to outdoor environment, resistant to surge and temperature changes.
· Adult Supplies: Small package and low power consumption characteristics to meet the needs of concealment and endurance.
4. Technical Analysis: Charging Process and Protection Mechanism
The CXLB73290E uses a multi-stage charging mode to ensure battery health and life:
· 0V and current elimination charging: When the battery voltage is lower than 2V, activate the battery with 1/20 set current; between 2V and 5.6V, the current elimination mode (1/10 current) is adopted.
· constant current charging: When the voltage rises to 5.6V ~ 8.4V, charge quickly with the set current.
· Constant Voltage and Cutoff: Turn to constant voltage mode when approaching 8.4V, and automatically stop charging when the current drops below 100mA.
· Automatic refill: When the battery voltage drops below 8.2V, restart the charging cycle.
The chip also has multiple protection functions:
· Input/output protection: Monitor VIN and BAT voltage, and turn off charging when abnormal.
· Temperature Management: When the junction temperature exceeds 140 ℃, the protection is triggered, and it will automatically recover after cooling.
· adaptive loop: Detect the input voltage through the VSEN pin and dynamically adjust the charging current to avoid overload of the adapter.
5. Design Guide: Key Parameters and Component Selection
5.1 charging current setting
The charge current is adjusted by the ICHG pin external resistor (RCS), and the formula is:
For example, when RCS = 6.8 kΩ, the charging current is 1A.
5.2 input and output capacitors
· VIN terminal: 100μF electrolytic capacitor and 1μF ceramic capacitor are connected in parallel to suppress surge and noise.
· VBS端：使用两颗22μF陶瓷电容靠近肖特基二极管，1μF电容靠近VBS引脚，提升稳定性。
5.3 inductance selection
· The 2.2μH CD54 power inductor is recommended, and the saturation current needs to be greater than 3.5A. Calculation formula:
5.4 PCB Layout Recommendations
· Power supply line width and short, reduce impedance and EMI.
· The LX loop is as short as possible, and the inductor is directly connected to the Schottky diode.
· The heat sink at the bottom of the chip is connected to the large area floor, and the heat dissipation is enhanced through the via hole.
6. common problems and solutions
6.1 charging time is too long
· Check the resistance of the ICHG resistor to ensure that the charging current is set correctly.
· Measure the VIN voltage and replace the adapter if it is low.
· The VSEN voltage is monitored and the chip automatically drops the current below 1.2V.
6.2 battery is not fully charged
· The floating voltage standard is 8.40V (1%), and it is normal for the battery voltage to fall naturally after full charge.
· Use a multimeter to check the charge cut-off voltage and confirm it is within the range of 8.316V ~ 8.484V.
6.3 charging indicator flashes
· Abnormal battery voltage (lower than 2V or higher than 8.65V), battery not connected or protection circuit trigger will cause flicker, need to check one by one.
6.4 chip fever serious
· Optimize the PCB heat dissipation design, increase the copper area, and add 6 to 9 vias under the heat sink.
· The charging current is set within 1A, and the current can be reduced appropriately if the heat dissipation is limited.
6.4 chip damage
· To ensure that the input/output voltage does not exceed 10V, to avoid inductive load anti-peak voltage, you can add a freewheeling diode or capacitor absorption.
7.Package and pin function
Eight, typical application schematic diagram
NineConclusion: choose JTM-IC, quality assurance
CXLB73290E with its high performance, high integration and comprehensive protection function, become the ideal solution for dual lithium battery charge management. As a JTM-IC (jtm-ic.com) is one of the core products, we are committed to providing customers with reliable chip technology and professional support to help product innovation and upgrading. For more details or technical support, please visit our official websitejtm-ic.comExplore more high-quality components and solutions.
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