CXLB73294 is a synchronous boost charging chip that supports 3.0V-6.5V input voltage, with a maximum charging current of 2A. It provides QFN-16 and ESSOP -500.00g package options, supporting 1.5A and 2A output respectively. All power MOSFETs are integrated inside the chip without external diodes, which greatly simplifies the peripheral circuit.
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[ CXLB73294 ]"
CXLB73294: high efficiency synchronous boost dual lithium battery charging chip comprehensive analysis
With the rapid development of portable devices and intelligent hardware, high-performance, high-security, high-integration battery charging management solutions have become the core competitiveness of product design. As a synchronous boost charging chip specially designed for dual lithium ion batteries, CXLB73294 is widely used in mobile power supply, intelligent door lock, portable game machine and other scenes with its 2A maximum charging current, 28V high withstand voltage, 96% peak efficiency and complete intelligent charging management function. This article will introduce the core characteristics of the CXLB73294, charging process, design points and typical applications, to help engineers to create an efficient, safe and compact charging system.
1. product overview: the perfect combination of high performance and high integration
CXLB73294 is a synchronous boost charging chip that supports 3.0V-6.5V input voltage, with a maximum charging current of 2A. It provides QFN-16 and ESSOP -500.00g package options, supporting 1.5A and 2A output respectively. All power MOSFETs are integrated inside the chip without external diodes, which greatly simplifies the peripheral circuit.
It has four-stage charging management (short circuit/current elimination/constant current/constant voltage), supports programmable charging parameters and multiple protection mechanisms, including input/battery dual 28V withstand voltage, NTC temperature monitoring, charging timeout protection, etc., to fully ensure system safety. In addition, the chip also integrates functions such as status indication, input adaptive current limit, and battery low power control, which is suitable for various portable and smart devices.
2. core features: efficient, safe, intelligent trinity
CXLB73294 excellence in efficiency, security and intelligent management:
· Efficient synchronization architecture: Peak efficiency 96%, heavy load efficiency 90%, significantly reduce heat generation.
· Wide voltage and high withstand voltage: Input 3.0V-6.5V, withstand voltage 28V, strong surge resistance.
· Four-stage charging management: Support SC/TC/CC/CV full charging, adapt to different battery status.
· Programmable parameters: Charging current, cut-off voltage, charging time, etc. can be set by external resistance.
Multiple protection mechanismsInput OVP, battery OVP, short circuit protection, thermal shutdown, NTC monitoring, etc.
· Intelligent status indication: STAT pin supports single/double LED indication, with fault flashing prompt.
· Low thermal resistance package: The thermal resistance of the ESSOP10 package is only 3.9 ℃/W, and the heat dissipation performance is excellent.
3. application areas: widely adapted to various types of electronic equipment
The CXLB73294 applies to the following typical scenarios:
· Mobile power supply: 2A fast charge support, high efficiency conversion, enhance the user experience.
· Intelligent door lock: High withstand voltage and low temperature charging support to ensure long-term reliable operation.
· Portable game machine: Compact design, support PSP, NDS and other devices.
· Audio Player & Phone Accessories: Low noise, high integration, suitable for space limited design.
4. working principle: four-stage charging and intelligent management
The CXLB73294 uses a four-stage charging strategy to accurately match the battery status:
4.1. Short circuit charging (SC)
When VBAT<2V, the chip wakes up the battery with 6% set current to avoid impact.
4.2. Current elimination charging (TC)
When the battery voltage rises to 2V-5.6V, the battery activity is restored at 12% of the set current.
4.3. Constant current charging (CC)
After the voltage exceeds 5.6V, the set current is quickly charged to quickly increase the power.
4.4. Constant voltage charging (CV)
Close to the set cut-off voltage to the constant voltage mode, the current gradually decreased until the cut-off.
4.5. Automatic cut-off and recharge
Charging ends when the current drops to 1/10 of the set value; it automatically restarts when the voltage drops to the recharge threshold.
5. Design Guide: Key Parameter Setting and Peripheral Selection
5.1. Charging current setting
Through the ICHG pin resistance setting, the formula is:
where constant current phase VICHG= 1V, the corresponding relationship between RICHG and current is as follows
| RICHG | constant current charging current | current elimination current | Short-circuit current |
|---|---|---|---|
| 2kΩ | 500mA | 60mA | 30mA |
| 1kΩ | 1000mA | 120mA | 60mA |
| 0.5kΩ | 2000mA | 240mA | 120mA |
External RCV resistor setting via CV pin:
| RCV | cut-off voltage |
|---|---|
| ≤ 2.5kΩ | 8.4V |
| 7.5kΩ | 8.6V |
| 25kΩ | 8.7V |
| ≥75kΩ | 8.8V |
Set the temperature window using external divider resistors and NTC thermistors:
· Recommended NTC:100K,B value 4250K
· Recommended configuration: R1 = 56kΩ,R2=150kΩ(0 ℃-60 ℃ range)
· Calculation formula:
5.4. Peripheral component selection
· Inductance L: 1μH-2.2μH, saturation current> 5A,DCR<20mΩ
· Input capacitance CIN: 10μF, withstand voltage ≥ 16V, low ESR ceramic capacitor
· Output Capacitor CBAT: 20μF, withstand voltage ≥ 16V, near BAT pin
· bootstrap capacitor CBST: 100nF, withstand voltage ≥ 10V
6. PCB Layout and Thermal Recommendations
· Power path: The SVIN-LX-BD-BAT path is as short and wide as possible to reduce loss and noise.
· Capacitor Layout: CBD, CBAT and CBST should be as close as possible to the corresponding pins of the chip.
· Grounding strategy: PGND and SGND are grounded separately, and the bottom heat dissipation pad is connected to the ground plane through multiple vias.
• Thermal design: The bottom of the ESSOP10 package needs to be covered with copper in a large area and through holes to improve heat dissipation performance.
7. Typical Problems and Solutions
· The charging current is not up to standardCheck RICHG resistance, input voltage and ILIM configuration.
· STAT light flashes abnormally: Check whether NTC voltage exceeds the range of 25%-65%, or check whether protection is triggered.
· Chip overheating: Optimize PCB heat dissipation design, reduce charging current or enhance heat conduction.
· Charging does not cut off: Confirm whether the BAT voltage reaches the set value and check the cut-off current setting.
8. package and pin function
Nine, typical application schematic diagram
10. Conclusion: Choosing JTM-IC to Inject Efficient Power into Smart Devices
With its high integration, high efficiency, high withstand voltage and comprehensive intelligent management functions, the CXLB73294 has become an ideal choice for dual lithium battery charging applications. Whether it is a mobile power supply, a smart door lock or a portable gaming device, CXLB73294 can provide a safe, stable and efficient charging solution. As a JTM-IC (jtm-ic.com) One of its high-efficiency power management chips, we are committed to providing customers with high-performance, high-reliability products and professional technical support. For more details, access to design resources or application samples, please visit JTM-IC official website:jtm-ic.com.
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