CXLB73271H is a linear charge management chip designed for single lithium ion/lithium polymer batteries, which integrates charge control and status indication functions. Its input voltage range is 4V-6V, which can withstand instantaneous surge voltage up to 28V and is compatible with 5V USB power supply and AC adapter. The chip has built-in power MOSFETs and anti-backflow function. The leakage current at the battery end is less than 1μa, which greatly improves the standby time.
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[ CXLB73271 ]"
With the increasing popularity of portable electronic devices, the safe and efficient charging of lithium batteries has become a crucial link in product design. CXLB73271H as a highly integrated single lithium battery linear charging management chip, it not only has a complete four-stage charging process and multiple safety protection mechanisms, but also supports up to 28V input withstand voltage and 1A programmable charging current, widely applicable to MP3/MP4, mobile multimedia devices and other portable products powered by USB or adapter. This article will comprehensively analyze the technical characteristics, application design points and its advantages in practical projects of the chip.
I. Product Overview
CXLB73271H is a linear charge management chip designed for single lithium ion/lithium polymer batteries, which integrates charge control and status indication functions. Its input voltage range is 4V-6V, which can withstand instantaneous surge voltage up to 28V and is compatible with 5V USB power supply and AC adapter. The chip has built-in power MOSFETs and anti-backflow function. The leakage current at the battery end is less than 1μa, which greatly improves the standby time.
CXLB73271H provides three packaging options: ESOP8, DFN2x2-8, and DFN3x3-8. You can flexibly select them according to space and heat dissipation requirements.
II. Core functions and features
2.1. Four-stage intelligent charging process
CXLB73271H strictly follow the lithium battery charging specifications, which are divided into four stages:
· Short Circuit charging (SC): safe wake-up for 0V battery, charging current is 5% of the set value
· Stream elimination charging (TC): when VBAT <2.9V, recover charging with 10% set current
· 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 current drops to 1/10 of the set value, the charging is automatically terminated and the charging cycle is restarted when the battery voltage drops to 4.0V.
2.2. High precision voltage and current control
·The charging voltage accuracy is ± 1%, supporting 4.2V/4.25V/4.3V/4.35V and other battery types
·The charging current is set by the external resistor of the PROG pin, and the maximum value is 1A.
·Current setting formula:
Above 300mA: IBAT=1000 /RPROG
Less than 300mA: IBAT=900 /RPROG
2.3. Multiple security protection mechanisms
2.3.1 input overvoltage/undervoltage protection: The overvoltage protection threshold is 6.5V and The Undervoltage lockout is 4.0V.
2.3.2 temperature protection:
·Turn off the output when the chip junction temperature exceeds 150℃
·NTC battery temperature detection is supported, and charging is suspended beyond the set range.
2.3.3Soft start and thermal regulation: Limit the starting impact current and automatically reduce the flow when the junction temperature rises.
2.3.4 ESD protection: All ports have ± 2000v HBM ESD protection
2.4. Status indication and enable control
· CHRG pin: output low level during charging, driving LED indication
· DONE pin: output low level after charging
· CE pin: High-level enable charging, low-level off, support MCU control
3. Typical application scenarios
·MP3/MP4 player and portable multimedia device: small size, low quiescent current suitable for embedded design
·USB rechargeable portable device: Compatible with 5V input, supports hot plug and surge protection
·Wearable devices and IoT terminals: battery anti-backfilling and low standby power consumption improve battery life
·Customized mobile power supply and charging set: Flexible encapsulation options and external programming capabilities
IV. Key Design Guidelines
4.1. Charging current setting
4.1.1Select the RPROG resistance based on the target current, for example:
·RPROG=1kΩ → IBAT= 1000mA
·RPROG=2kΩ → IBAT= 500mA
4.1.2We recommend that you select a resistor with an accuracy of 1% to ensure the accuracy of the current.
4.2. Temperature detection configuration
4.2.1 Use 100kohm NTC thermistor (B = 4250K) and divider resistance to build a detection network
4.2.2 Protection threshold:
·4. 2.VTEMP>80%×VCC& rarr; High temperature
·VTEMP<45%×VCC& rarr; Low temperature
4.2.3 if temperature detection is not enabled, ground the TEMP pin
4.3. PCB layout and heat dissipation suggestions
· The VCC and BAT pins are arranged with 10μF ceramic capacitors nearby, and 0.1μF decoupling is added in high-frequency noise sensitive occasions.
· The bottom heat dissipation pad of the chip connects a large area of copper cover and connects to the mainland layer through multiple vias.
· PROG resistor wiring should be short and straight away from heat source and noise source
4.4. Status indicator circuit
· CHRG and DONE are open-drain outputs, and external LED and current limiting resistor are required (1kΩ is recommended)
· If the indication function is not used, the corresponding pin should be grounded.
V. Thermal management and power optimization
To maintain high charging current and control temperature rise:
· Make full use of PCB copper layer and via hole for heat dissipation, especially in DFN package
· When the input voltage is high, small resistance resistor (such as 1Ω) can be connected in series to share power consumption and reduce chip temperature rise.
· Avoid arranging other heat sources around the charging IC in the actual layout.
VI. Selection and technical support
JTM-IC (official website:jtm-ic.com) provide complete support for CXLB73271H full series models:
· CXLB73271HE: ESOP8 package, suitable for general applications
· CXLB73271HD2: DFN2x2-8, suitable for ultra-compact design
· CXLB73271HD3: DFN3x3-8, better heat dissipation performance
We provide data manuals, reference designs, PCB layout guides and sample services to help customers quickly promote product development.
VII. Schematic diagram of typical applications
8. Packaging and pin functions
Nine,Conclusion
CXLB73271H has become an ideal solution for charging management of single lithium battery due to its high integration, high reliability and flexible configurability. Whether in consumer electronics or industrial equipment, the chip can provide efficient charging performance and good user experience on the premise of ensuring safety. Welcome to the JTM-IC official website for more technical resources and product information. We will provide you with professional power management solutions and all-round technical support.
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