With the rapid development of portable equipment, miner's lamp, emergency power supply and Internet of things equipment, efficient, safe and small volume battery charging management scheme has become the core requirement of product design. As a linear charging management integrated circuit designed for single-section lithium iron phosphate battery, CXLB73319 integrates power transistor, current detection, reverse connection protection and status indication, and can realize complete charging management without external discrete components. This paper will comprehensively introduce the application value of CXLB73319 in practical projects from the aspects of chip characteristics, working principle, typical application and JTM-IC technical advantages.
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[ CXLB73319 ]"
CXLB73319: high precision, high integration single-cell lithium iron phosphate battery linear charge management chip
With the rapid development of portable equipment, miner's lamp, emergency power supply and Internet of things equipment, efficient, safe and small volume battery charging management scheme has become the core requirement of product design. As a linear charging management integrated circuit designed for single-section lithium iron phosphate battery, CXLB73319 integrates power transistor, current detection, reverse connection protection and status indication, and can realize complete charging management without external discrete components. This paper will comprehensively introduce the application value of CXLB73319 in practical projects from the aspects of chip characteristics, working principle, typical application and JTM-IC technical advantages.
1. Chip Overview and Core Features
CXLB73319 is a highly integrated single-section lithium iron phosphate battery charging management chip, using SOT23-6 package, minimalist peripheral circuit design makes it very suitable for space-constrained portable devices. Its main features include:
· Designed for lithium iron phosphate: Constant voltage charging voltage 3.7V, accuracy 1%;
· Fully integrated architecture: Built-in power tube, no external blocking diode and current detection resistor;
· Wide input voltage range4.0V ~ 9.0V, compatible with USB and adapter power supply;
· Three-stage intelligent charging: Pre-charge, constant current, constant voltage, support constant temperature control;
Adjustable charging current: Maximum continuous charging current 700mA, set by external resistor;
· Low power sleep mode: Battery current consumption <3μA when the input is powered off;
· Two-way status indicationCHRG and CHRGT output charging status and end signal;
· Battery reverse connection protection: Automatic shutdown when the battery is connected in reverse to protect the chip and system;
C/10 cutoff and automatic recharge: Intelligent judgment of charging end and re-trigger.
2. Pin Functions and Typical Circuits
CXLB73319 in SOT23-6 package, pin definition is simple and clear:
· CHRG: Charging status indicator (open drain), often bright during charging;
· GND: Power supply ground;
· BAT: Battery positive connection terminal, providing charging current and voltage;
· Wine: Power input positive pole;
· CHRGT: End of charge indication (open drain), always on when fully charged;
· PROGCharging current setting and monitoring terminal, external resistor setting current.
In a typical application circuit, a complete charging function can be realized only by connecting a 1μF bypass capacitor between VIN and GND, a 4.7 ~ 10μF capacitor between BAT and GND, and a set resistor between PROG and GND.
3. charging process and working mechanism
The charging process of the CXLB73319 is divided into three stages, the whole process is controllable, safe and reliable:
3.1. Pre-charge phase
When the battery voltage is lower than 2.0V, the chip pre-charges the battery with a small current of 10% in constant current mode to restore the deep discharge battery.
3.2. Constant current charging stage
After the battery voltage exceeds 2.0V, it enters the constant current charging mode, and the charging current is set by the external resistor RPROG of the PROG pin:
For example, when RPROG = 2.3 kΩ, the charging current is about 500mA.
3.3. Constant voltage charging phase
When the battery voltage approaches 3.7V, it enters the constant voltage mode and the current gradually decreases. When the current drops to 10% of the constant current value (C/10), charging ends and CHRGT outputs a low level.
In addition, if the battery voltage drops below the recharge threshold (about 3.4V), the system automatically starts a new charging cycle.
4. key functions and design points
4.1. Thermal regulation and power management.
The chip has a built-in temperature adjustment circuit, which automatically reduces the charging current when the junction temperature exceeds about 90°C to prevent overheating damage and improve system reliability.
4.2. Status indication logic
|
CHRG |
CHRGT |
Status Description |
|---|---|---|
|
Low |
High |
Charging |
|
High |
Low |
Charging complete |
|
High |
High |
No input, sleep, or reverse battery |
4.3. Sleep mode and UVLO
When VIN is lower than BAT voltage by 10mV, the chip enters sleep mode with battery current <3μA; when VIN is lower than 3.2V ~ 3.8V, it enters UVLO state and charging is prohibited.
4.4. Battery reverse connection protection
When the battery is connected in reverse, the chip will stop immediately, the status indicator will be completely extinguished, and the battery will be automatically restored after removal, effectively protecting the safety of the system.
4.5. PCB Layout Recommendations
· PROG resistor should be close to the chip to reduce parasitic capacitance;
· VIN and BAT capacitors should be close to the chip pins;
· GND pin copper area should be as large as possible to improve the heat dissipation capacity;
· The bottom metal plate of the chip should be soldered to the PCB ground plane to optimize heat dissipation.
5. typical application scenarios
CXLB73319 are widely used in the following areas:
· Miner's lamp and emergency lighting equipment
· Portable Medical Equipment
· Internet of Things Terminal and Sensor Node
· Electric toys and personal care equipment
· Lithium iron phosphate battery backup power system
Its high integration, low peripheral requirements, high reliability and other characteristics make it an ideal choice for small size, low cost and high efficiency charging systems.
6.Typicalapplication circuitand BOM recommendations
SevenJTM-IC and CXLB73319
As an important part of the JTM-IC's low-voltage, low-current battery management product line, the CXLB73319 reflects the company's technical accumulation in highly integrated analog chip design. The JTM-IC is committed to providing customers with the whole process support from chip selection, reference design to system debugging, helping customers quickly realize productization and enhance market competitiveness.
If you need to obtain CXLB73319 samples, technical information or apply for technical support, please visit JTM-IC official website:jtm-ic.comOr contact our sales and technical support team.
Eight, the article summary：
CXLB73319 is a highly integrated linear charging management chip designed for single-section lithium iron phosphate battery. It has the advantages of full integration, high precision, reverse connection protection and low power consumption. It is suitable for all kinds of portable devices and emergency power supply systems. As a supplier of this product, JTM-IC provide complete technical support and solutions to help customers create efficient, safe and compact battery charging systems.
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