The CXLB73289 is packaged in MSOP-10 and supports various battery types such as 4.2V/4.3V/4.35V/4.4V (single section) and 8.4V/8.6V/8.7V/8.8V (double section). It has a high-efficiency PWM control mechanism and the switching frequency is fixed at 600kHz. The charging process is divided into three stages: pre-charging (Pre-charge), constant current charging (CC) and constant voltage charging (CV), effectively ensuring battery life and charging safety.
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[ CXLB73289 ]"
CXLB73289 high-precision single/double lithium battery charging management chip: intelligent charging and comprehensive protection scheme
With the increasing popularity of portable electronic devices, efficient, safe and intelligent battery charging management solutions have become the core of product design. As a switch-type charging management chip designed for single-cell or dual-cell lithium-ion/lithium-polymer batteries, CXLB73289 integrates high-precision voltage and current regulation, intelligent charging status indication, and multiple protection mechanisms. It is widely used in handheld devices, chargers, mobile instruments and other scenarios. This article will comprehensively analyze the technical characteristics, working principles and typical applications of the CXLB73289 to help engineers build an efficient and reliable battery charging system.
1. Chip Overview and Core Features
The CXLB73289 is packaged in MSOP-10 and supports various battery types such as 4.2V/4.3V/4.35V/4.4V (single section) and 8.4V/8.6V/8.7V/8.8V (double section). It has a high-efficiency PWM control mechanism and the switching frequency is fixed at 600kHz. The charging process is divided into three stages: pre-charging (Pre-charge), constant current charging (CC) and constant voltage charging (CV), effectively ensuring battery life and charging safety.
The chip has the following outstanding features:
· High precision voltage controlCharging voltage accuracy of ± 0.5%, support multi-level battery voltage;
· Programmable charging current: Flexible setting of constant current charging current through external resistor;
· Intelligent battery detection: Automatically identify battery access status and support timeout error recovery;
Multiple protection mechanisms: Including overvoltage protection, short circuit protection, temperature protection, etc;
· Charging status indication: LED is driven by STAT1 and STAT2 pins to display the charging status in real time;
Wide voltage input and low power consumption: The input pin has a withstand voltage of 20V, and the battery discharge current is extremely low in sleep mode;
· Adjustable charging time: Set the charging time limit through the TTC pin external capacitor.
2. Pin Functions and Typical Application Circuits
The 10 pins of the CXLB73289 have clear functions to build a complete charge management system:
· STAT1/STAT2: Charging state indication output;
· VCC: Power input;
· GATE: Switch drive output;
· GND: simulation ground;
· TTC: external capacitor set charging time;
· BAT: Battery voltage detection;
· SNS: Positive terminal of current detection;
· ISET: Charging current setting;
· VTRIM: Constant pressure value fine adjustment.
In the typical application circuit, the charging parameters are set by external resistors and capacitors, combined with the built-in protection mechanism, to ensure the safe and reliable operation of the system under various working conditions.
3. charging process and intelligent management
The charging process of the CXLB73289 is divided into three stages, and the whole process can be controlled and monitored:
3.1. Pre-charge phase: When the battery voltage is lower than the set threshold (single 3V/double 6V), pre-charge with a small current to activate the battery;
3.2. Constant current charging stage: After the battery voltage rises to the set value, it is quickly charged with a constant high current;
3.3. Constant voltage charging phase: When the battery is close to full charge, it turns to constant voltage mode, and the current gradually decreases until the charging is cut off.
The chip also has a recharging function, which automatically restarts charging when the battery voltage drops due to self-discharge, keeping the battery always in the best condition.
4. key parameters and design points
4.1. Current setting
The constant current charging current is determined by the following formula:
Among them, KISET= 2000V/A,VISET= 1V (constant current phase). The precharge current is 20% of the constant current value, and the cut-off current is 10%.
4.2. Voltage Trim
Through the VTRIM pin external resistor, the constant voltage output value can be fine-tuned. For example, for dual batteries:
where R = 40kΩ.
4.3. Charging time setting
The total charging time is determined by the external capacitor of the TTC pin:
of which kTTC= 4.66H/10nF. The precharge time is 1/8 of the total time.
5. Protection Mechanism and Fault Handling
CXLB73289 integrated protection features ensure system security:
· Overvoltage protection: Turn off PWM immediately when the battery voltage exceeds 117% of the set value;
· Short circuit protection: When the battery voltage is detected to be too low, enter the short-circuit mode to limit the charging current;
· Temperature protection: Built-in 125 ℃ overheat protection to prevent chip damage;
· Timeout RecoverySupport intelligent recovery mechanism for pre-charge and total charge timeout errors.
6. status indication and user interface
Through the two-color LED indication of STAT1 (green light) and STAT2 (red light), the user can intuitively understand the system status:
· Extuns/Extuns: No charge, no battery or sleep mode;
· off/on: Charging;
· On/off: Charging is completed;
· off/0.5Hz pulse: Fault status (timeout or overvoltage).
7. Packaging and Supply Chain Support
The CXLB73289 uses a MSOP-10 package, compact size, suitable for space-constrained application scenarios. JTM-IC (jtm-ic.com) Provide a full range of models and technical support to help customers quickly advance product design and mass production.
8. epilogue
CXLB73289 with its high precision, high integration and multiple protection functions, become the ideal choice for single/double lithium battery charging management. Whether it is a handheld device, a mobile instrument or a variety of chargers, the chip can provide a safe, efficient and reliable charging solution. welcome to visit JTM-IC official website for more product details and technical information, for your next generation of portable devices to inject wisdom power.
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