CXLB73270H is a highly integrated single lithium ion/lithium polymer battery linear charging management chip, which integrates charging control and status indication functions. Its input voltage working range is 4V-6V, which can withstand instantaneous surge voltage up to 28V and is perfectly compatible with 5V USB power supply and AC adapter. The chip is packaged in compact SOT23-5 and SOT23-6, and the simple external component requirements make it especially suitable for portable devices with limited space.
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[ CXLB73270 ]"
With the rapid development of portable electronic devices, efficient and safe battery charging management solutions have become the core requirements of product design. As a high-performance single-cell lithium battery linear charging management chip, CXLB73270H has become MP3/MP4, with its 24V high input withstand voltage, 500mA programmable charging current, complete four-stage charging process and ultra-low standby power consumption, ideal for portable products such as mobile multimedia devices. This article will deeply analyze the technical characteristics, design points and application advantages of the chip, and help engineers to create a safer and more efficient charging system.
I. Product Overview
CXLB73270H is a highly integrated single lithium ion/lithium polymer battery linear charging management chip, which integrates charging control and status indication functions. Its input voltage working range is 4V-6V, which can withstand instantaneous surge voltage up to 28V and is perfectly compatible with 5V USB power supply and AC adapter. The chip is packaged in compact SOT23-5 and SOT23-6, and the simple external component requirements make it especially suitable for portable devices with limited space.
CXLB73270H built-in anti-backfilling circuit, the leakage current at the battery end is less than 1μa, effectively extending the standby time. Its strict four-stage charging process and multiple protection mechanisms ensure the safety and service life of the battery throughout the charging cycle.
II. Core functions and features
2.1 intelligent four-stage charging process
CXLB73270H strictly follow the charging specifications of lithium batteries to achieve controllable charging management throughout the process:
· Short Circuit charging (SC): wake up the 0V battery safely. The charging current is 5%-7% of the set value.
· Stream elimination charging (TC): when 2.65v
· Constant current charging (CC): After VBAT> 2.9V, charge quickly with full set current
· Constant voltage charging (CV): When the voltage reaches 4.2V, it changes to constant voltage mode, and the current gradually decreases.
When the charging current drops to 1/10 of the set value, it will automatically terminate and restart the charging automatically when the battery voltage drops to 95.7% VC.
2.2. High-precision charging management
2.2.1Charging voltage accuracy ± 1%, support 4.2V/4.25V/4.3V/4.35V and other battery types
2.2.2 the charging current is set by the external resistor of PROG pin, and the maximum charging current is 500mA.
2.2.3 Current setting formula: IBAT=(VPROG/RPROG) × 1000
Where VPROGIn the constant current phase, it is 1v. Typical configuration:
·RPROG =2kΩ → IBAT= 500mA
·RPROG =2.5kΩ → IBAT= 400mA
·RPROG =10kΩ → IBAT= 100mA
2.3. Comprehensive security protection mechanism
·Input overvoltage/undervoltage protection: overvoltage protection threshold 6.25V, undervoltage locking threshold 4.0V
·Temperature Protection: automatically turn off the output when the chip junction temperature exceeds 150 ℃
·Thermal regulation function: automatically reduces the charging current when the junction temperature rises to prevent overheating damage
·Soft start control: limit surge current during startup to improve system reliability
·ESD protection: All ports have ± 2000v HBM ESD protection
2.4. Flexible status indication
·CHRG pin: output low level during charging, driving LED indication
·FULL pin(SOT23-6): output low level after charging
·Support Battery unconnected alarm (LED flashing) and fault status indication
3. Typical application scenarios
·MP3/MP4 player and portable multimedia device: small package and low quiescent current suitable for embedded design
·USB rechargeable portable device: Compatible with 5V input, supports hot plug and surge protection
·IoT terminals and wearable devices: battery anti-backfilling and 1. A standby leakage current to improve battery life
·Various customized mobile power supplies: flexible posture indication and external programming capabilities
IV. Key Design Guidelines
4.1. Charging current setting
Select RPROG resistance based on the target current. We recommend that you select a resistor with an accuracy of 1% to ensure the current accuracy. The PROG pin wiring should be short and straight away from the heat source and noise source.
4.2. Selection of peripheral components
·Input/output capacitor: VCC and BAT pins are respectively connected to 10 μF ceramic capacitors (withstand voltage ≥ 16V)
·LED current limiting resistor: the typical value is 1kΩ, which can be adjusted according to brightness requirements.
·High voltage interface protection: If there is a voltage spike, the 1Ω resistor can be connected in series in front of the VCC capacitor.
4.3. PCB layout suggestions
·The input capacitor should be close to the VCC and GND pins as much as possible, and 0.1μF decoupling capacitor should be added in high frequency occasions.
·High current path (VCC, BAT, GND) uses large area copper cover paving design
·Make full use of passing holes to connect the surface layer and the ground plane of the inner layer to improve heat dissipation and noise suppression.
4.4. Status indication configuration
·CHRG and FULL are open-drain outputs, and external LED and current limiting resistor are required.
·If the indication function is not applicable, the corresponding pin should be left empty.
V. Thermal management and reliability design
To maintain stable charging current and control temperature rise:
·Make full use of PCB copper layer heat dissipation in SOT23 package to avoid continuous high temperature work of chip
·When the input voltage is high, the internal thermal adjustment function of the chip automatically reduces the flow to prevent overheating.
·Keep away from other heat sources during layout to ensure that the charging IC is in a relatively low temperature environment.
VI. Selection and technical support
JTM-IC (official website:jtm-ic.com) provide complete product support for CXLB73270H:
·CXLB73270H6: SOT23-6 package with CHRG and FULL dual indication functions
·CXLB73270H5: SOT23-5 package, suitable for more compact design
We provide complete data manuals, reference designs, PCB layout guides and sample services to help customers accelerate product development and listing processes.
VII. Schematic diagram of typical applications
8. Packaging and pin functions
Nine,Conclusion
With its high integration, high reliability and simple external requirements, CXLB73270H has become a high-quality solution for charging management of single lithium battery. Whether in consumer electronics or industrial portable devices, the chip can provide safe, efficient and stable charging performance in limited space. Welcome to the JTM-IC official website for more technical information and product information. We look forward to providing you with professional power management solutions and all-round support services.
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