• [ CXLB73298 ]"

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Introduction

With the increasing demand for battery capacity and power in portable devices, efficient charging solutions that support multiple series-connected lithium batteries are becoming increasingly important. As an intelligent boost charge management chip that supports 2 or 3 strings of lithium batteries, CXLB73298 is an ideal choice for large-capacity battery charging applications with its 15W high power output, flexible voltage configuration and comprehensive protection functions. This article will fully analyze the technical characteristics of the CXLB73298, application design and configuration methods, and provide engineers with a complete design reference.IsJ嘉泰姆

1. CXLB73298 Chip Overview

CXLB73298 is an efficient synchronous boost charge management chip designed for 2 or 3 strings of Li-ion/polymer batteries. The ESOP8 package, integrated power MOSFET and synchronous switch architecture greatly simplifies the peripheral circuit and significantly reduces the system BOM cost.IsJ嘉泰姆

Core parameters:IsJ嘉泰姆

·    Input voltage range: 4.5V-5.5V(5V adapter)IsJ嘉泰姆

·    Maximum output power: 15WIsJ嘉泰姆

·    Constant current charging current: 1.2AIsJ嘉泰姆

·    Switching frequency: 500KHzIsJ嘉泰姆

·    Conversion efficiency: 5V input, 8V/1.2A output up to 93%IsJ嘉泰姆

The chip supports flexible configuration of charging voltage through external resistors, and the same hardware design is compatible with 2-string and 3-string battery applications, greatly improving design flexibility.IsJ嘉泰姆

2. core features and benefits

2.1. High performanceIsJ嘉泰姆

·    Synchronous Boost Architecture with 93% Peak EfficiencyIsJ嘉泰姆

·    500KHz switching frequency, support the use of 2.2μH small inductorIsJ嘉泰姆

·    Efficiency remains 91% at 12V/1A outputIsJ嘉泰姆

2.2. Flexible voltage configurationIsJ嘉泰姆

·    Adjusting the charging voltage via external resistor of VSET pinIsJ嘉泰姆

·    Supports 2 strings (8.1V-8.4V) and 3 strings (12.3V-12.6V) batteriesIsJ嘉泰姆

·    Suspended default 8.4V(2 strings) or 12.6V(3 strings)IsJ嘉泰姆

2.3. Intelligent charging managementIsJ嘉泰姆

·    Four-stage charging: short circuit & rarr; current elimination & rarr; constant current & rarr; constant voltageIsJ嘉泰姆

·    Elimination of current charge: 100mA (recovery depth discharge battery)IsJ嘉泰姆

·    Constant current charging: 1.2A (fast charging)IsJ嘉泰姆

·    Constant voltage charging: ensure the battery is fully chargedIsJ嘉泰姆

2.4. Comprehensive protection mechanismsIsJ嘉泰姆

·    NTC temperature protection: support battery temperature monitoringIsJ嘉泰姆

·    Input undervoltage/overvoltage protectionIsJ嘉泰姆

·    Output overcurrent, overvoltage, short circuit protectionIsJ嘉泰姆

·    IC over-temperature protection (135 ℃ shutdown)IsJ嘉泰姆

·    Charging timeout protectionIsJ嘉泰姆

3. typical application scenarios

CXLB73298 are ideal for the following applications:IsJ嘉泰姆

·    Large capacity mobile power supply: support 15W fast charge, excellent efficiencyIsJ嘉泰姆

·    Portable toolsPower tools, gardening equipment, etc.IsJ嘉泰姆

·    Medical EquipmentPortable monitors, treatment equipmentIsJ嘉泰姆

·    Industrial EquipmentData collector, test instrumentIsJ嘉泰姆

·    Consumer ElectronicsHigh-end Bluetooth speaker, portable displayIsJ嘉泰姆

Its flexible voltage configuration allows the same PCB design to adapt to the needs of different battery configurations, significantly reducing development costs.IsJ嘉泰姆

4. detailed charging process analysis

The CXLB73298 uses an intelligent four-stage charging algorithm to ensure that the battery is safe and fully charged:IsJ嘉泰姆

4.1. 2 string battery application:IsJ嘉泰姆

·    Short circuit charging: When the battery voltage is <3.7V, charge with 50mA currentIsJ嘉泰姆

·    current elimination charging: When 3.7V IsJ嘉泰姆

·    constant current charging: When the battery voltage is> 6V, fast charging with 1.2A constant currentIsJ嘉泰姆

·    constant voltage charging: Turn to constant voltage mode when approaching the set voltageIsJ嘉泰姆

4.2. 3 string battery applications (CXLB73298-3S):IsJ嘉泰姆

·    Short circuit charging: When the battery voltage is <3.7V, charge with 50mA currentIsJ嘉泰姆

·    current elimination charging: When 3.7V IsJ嘉泰姆

·    constant current charging: When the battery voltage is> 9V, charge with 1.2A constant currentIsJ嘉泰姆

·    constant voltage charging: Turn to constant voltage mode when approaching 12.6VIsJ嘉泰姆

4.3. Automatic recharge function: After the battery is fully charged, if the voltage drops (2 strings to 8V,3 strings to 12V), the chip will automatically restart the charging cycle.IsJ嘉泰姆

5. Critical Circuit Design Guide

5.1. Charging voltage setting

Set the charging voltage via the VSET pin external resistor:IsJ嘉泰姆

5.2. NTC Temperature Protection Configuration

·    NTC pin outputs 20μA current, detects NTC resistance voltage dropIsJ嘉泰姆

·    Normal temperature: 0.56V-1.32V(100% charging current)IsJ嘉泰姆

·    High temperature: 0.43V-0.56V(50% charging current)IsJ嘉泰姆

·    Abnormal temperature:<0.43V or> 1.32V (stop charging)IsJ嘉泰姆

·    Disable NTC: connect NTC pin to 51K resistor to groundIsJ嘉泰姆

5.3. LED status indication

5.3.1 Single lamp scheme:IsJ嘉泰姆

·    Charging: LED is always onIsJ嘉泰姆

·    Full: LED offIsJ嘉泰姆

·    Abnormal: LED flashingIsJ嘉泰姆

5.3.2. Double lamp scheme:IsJ嘉泰姆

·    Charging: LED2 onIsJ嘉泰姆

·    Full: LED1 brightIsJ嘉泰姆

·    Abnormal: Double lights flashing alternatelyIsJ嘉泰姆

Recommendations for selection of 6. components

Based on typical applications, key components include:IsJ嘉泰姆

·    power inductance: 2.2 μH, saturation current> 5A,DCR<20mΩIsJ嘉泰姆

·    VSYS Capacitor2 × 22 μF/25V ceramic capacitor (close to VSYS pin)IsJ嘉泰姆

·    VIN Capacitor10 μF/25V ceramic capacitor (input filter)IsJ嘉泰姆

·    VOUT CAPACITANCE: 10 μF/25V ceramic capacitor (battery terminal voltage regulator)IsJ嘉泰姆

·    bootstrap capacitance：0.1μF/16V（BST-LX间）IsJ嘉泰姆

·    LED current limiting resistor: 100 Ω (adjustable according to brightness)IsJ嘉泰姆

Important Recommendations for 7. PCB Layout

Proper PCB layout is critical to system performance and stability:IsJ嘉泰姆

7.1. Power path optimizationIsJ嘉泰姆

·    The VSYS capacitor is close to the chip pin and is directly connected to GNDIsJ嘉泰姆

·    LX node trace short and thick, reduce switching noiseIsJ嘉泰姆

·    High current path using large area copper cladIsJ嘉泰姆

7.2. Thermal designIsJ嘉泰姆

·    The bottom ePad is connected to a large area of copper sheet and punched for heat dissipation.IsJ嘉泰姆

·    Keep proper distance between power inductor and chipIsJ嘉泰姆

·    Use multiple vias to connect each layer of ground planeIsJ嘉泰姆

7.3.  signal isolationIsJ嘉泰姆

·    VSET, NTC and other signal lines away from the LX switch nodeIsJ嘉泰姆

·    Sensitive signals use SGND, separate from power groundIsJ嘉泰姆

·    NTC resistance away from heating components (such as chips, inductors)IsJ嘉泰姆

7.4.  Capacitor LayoutIsJ嘉泰姆

·    The VSYS capacitor has the highest priority and must be closest to the pinIsJ嘉泰姆

·    Nearby placement of input and output capacitors to reduce ESR and ESLIsJ嘉泰姆

8. Typical Application Bill of Material

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Based on typical application schematics, the main components include:IsJ嘉泰姆

7.1.  IC:CXLB73298 or CXLB73298-3S × 1IsJ嘉泰姆

7.2.  Inductance: 2.2μH power inductance × 1IsJ嘉泰姆

7.3.  Capacitance: 22μF × 2,10μF × 2,0.1μF × 1IsJ嘉泰姆

7.4.  Resistance: VSET setting resistor × 1,LED current limiting resistor × 1IsJ嘉泰姆

7.5.  LED: monochrome or two-color LED × 1-2IsJ嘉泰姆

9. technical support and supply information

JTM-IC（jtm-ic.com) As the official authorized supplier of CXLB73298 series, provide comprehensive technical support:IsJ嘉泰姆

9.1.  Sample application and bulk supply serviceIsJ嘉泰姆

9.2.  Reference design, PCB review and optimization suggestionsIsJ嘉泰姆

9.3. Professional and technical Q & A and customized solution developmentIsJ嘉泰姆

9.4. Complete design documents, data sheets and application notes.IsJ嘉泰姆

Ten,Package and pin function

XI, epilogue

With its high integration, flexible configuration and comprehensive protection functions, the CXLB73298 has become the preferred solution for 2 string/3 string lithium battery charging applications. Whether in large-capacity mobile power supplies, industrial equipment or high-end consumer electronics, its excellent performance and reliability can provide strong support for end products. Welcome to visitJTM-IC official websiteGet detailed technical information, apply for samples or consult professional design support.IsJ嘉泰姆

XII,Related Chip Selection Guide Download ► More similar products....

Multiple Battery Charge Management Chips.pdf (289.07 KB)

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