CXLB73292 is a synchronous architecture boost charge management chip designed for dual Li-ion/polymer batteries. Its wide input voltage range is 2.7V-7V, supports a maximum 3A charging current, and has a conversion efficiency of up to 95%. The chip has integrated input overvoltage protection (OVP) with a maximum withstand voltage of 16V, which can effectively resist high voltage shocks such as misinsertion and hot plug to ensure system safety.
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CXLB73292: high efficiency synchronous boost dual lithium battery charging chip comprehensive analysis
Today, all kinds of portable electronic devices have higher and higher requirements for battery life and charging efficiency. A high-performance, highly integrated, safe and reliable charging management chip has become the key to product success. As a synchronous boost type dual-section lithium battery charging management chip supporting 2.7 V-7V wide input voltage and maximum 3A charging current, CXLB73292 is widely used in electronic cigarettes, Bluetooth equipment, mobile power supply and various 2-string battery packs and other scenes due to its advanced features such as high withstand voltage, true disconnection and NTC temperature protection. This article will comprehensively introduce the CXLB73292 from the characteristic analysis, working principle, design guide to typical application, and help engineers to create an efficient and safe charging system.
1. product overview: the perfect combination of high performance and high integration
CXLB73292 is a synchronous architecture boost charge management chip designed for dual Li-ion/polymer batteries. Its wide input voltage range is 2.7V-7V, supports a maximum 3A charging current, and has a conversion efficiency of up to 95%. The chip has integrated input overvoltage protection (OVP) with a maximum withstand voltage of 16V, which can effectively resist high voltage shocks such as misinsertion and hot plug to ensure system safety.
The chip uses ESSOP-10 package, small size, easy to SMT patch and post-welding, very suitable for space-constrained portable products. Its built-in input power adaptive function can intelligently identify weak power adapters and automatically adjust the charging current to avoid system restart or damage due to input overload.
2. core features: multiple protection and intelligent management
CXLB73292 excellence in performance, security and intelligent management:
· Efficient synchronization architecture: The highest conversion efficiency of 95% significantly reduces heat generation and improves battery life.
· High input withstand voltage and OVP: Support 16V input withstand voltage, OVP threshold 7.1V, effective protection against voltage surges.
· Real break function: In the short circuit or shutdown state completely cut off the input and output, to prevent the voltage back.
· NTC temperature protection: Support external thermistor to realize high and low temperature charging protection.
· Flexible status indication: The STATS pin supports single lamp/dual lamp mode, and the charging status is clear at a glance.
· Programmable charging parameters: Charging current and cut-off voltage can be flexibly set through external resistor.
3. application areas: widely adapted to a variety of portable devices
The CXLB73292 applies to the following typical scenarios:
· Electronic Cigarettes: Efficient charging and real off function to ensure safe use.
· Bluetooth speaker/headset: Small size, high efficiency suitable for compact design.
· Mobile power supply: Support 3A high current fast charging to enhance user experience.
· All kinds of 2 series battery pack: such as power tools, portable medical equipment, etc.
4. function details: charging management and system protection
4.1. Multi-stage charging management.
The CXLB73292 adopts pre-charging, constant current, constant voltage three-stage charging:
· Pre-charge: When the battery voltage is lower than 5.7V, charge safely at 1/10 of the set current.
· constant current charging: After the battery voltage rises, charge quickly at the set current.
· Constant pressure stage: When the voltage is close to the set cut-off value, it will automatically switch to constant voltage mode, and the current will gradually decrease.
4.2. Charging parameter setting
4.2. 1 Cut-off voltage setting: Set by VTERM pin external resistor RVTERM, the formula is:
4.2. 2 Charging current setting: Set via ISET pin resistance, for example:
· Riset=10kΩ → 0.5A
· Riset=2kΩ → 2.5A
4.3. NTC Temperature Protection Configuration
Set the temperature window via external divider resistor and NTC thermistor:
· Overcooling point threshold: 75% × VLDO
· Hot spot threshold: 25% × VLDO over
RTS1 and RTS2 can be calculated by the following formula:
4.4. True Break and Anti-backflow
In the shutdown or fault state, the chip completely cut off the input and output path, to prevent the battery voltage reverse input source, improve system reliability.
5. Design Guide: Selection and Layout of Key Peripheral Components
5.1. Inductor Selection
It is recommended to use 2.2μH power inductor with saturation current ≥ 7A to support 3A charging and peak current.
5.2. Capacitor configuration
· Input capacitance CIN: 22 μF low ESR ceramic capacitor to suppress input voltage fluctuations.
· Output Capacitors CBAT/CSYS: 22 μF ceramic capacitor, stable output voltage and battery voltage.
· BST capacitance10nF ceramic capacitor, connect BST to SW pin.
5.3. PCB Layout Recommendations
· The power path (IN-SW-BAT) is as short and wide as possible to reduce parasitic parameters and losses.
· The capacitor is as close as possible to the chip pin, and the ground wire adopts star grounding or large-area ground laying.
· PGND is connected to the signal ground points to avoid noise coupling.
6. Typical Problems and Solutions
· The charging current is not up to standard: Check if ISET resistance and input voltage are within range.
· STATS Indicator Abnormal: Confirm that the pin is configured for single lamp/dual lamp mode, and check the external current limiting resistor.
· Chip overheating protection: Optimize heat dissipation design, reduce charging current or strengthen PCB heat conduction.
· NTC protection false trigger: Check the thermistor network configuration and confirm that the RTS1/RTS2 resistance is calculated correctly.
7.Package and pin function
Eight, typical application schematic diagram
NineConclusion: Choose JTM-IC to inject efficient power into the product.
CXLB73292 with its high integration, high efficiency and comprehensive system protection function, become the ideal choice for dual lithium battery charging applications. As a JTM-IC (jtm-ic.com) One of its key power management chips, we are committed to providing customers with high-performance, high-reliability solutions and professional technical support. If you are looking for an efficient charging chip for portable devices, please visit JTM-IC official website (jtm-ic.com) Learn more about product information, design resources and sample application methods
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