The CXLB73330 is packaged in a MSOP-10 package, with a high-efficiency PWM control mechanism, a switching frequency of 600kHz, a wide input voltage range, and a maximum withstand voltage of 20V. The charging process is divided into three stages: pre-charging (Pre-charge), constant current charging (CC) and constant voltage charging (CV), which can effectively extend battery life and improve charging efficiency.
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[ CXLB73330 ]"
CXLB73330 efficient battery charge management chip: full support for multi-cell lithium battery and lead-acid battery charging solutions
In the context of the widespread popularity of portable electronic devices, efficient and safe battery charging management has become an indispensable part of product design. As a high-performance switching charging management chip, CXLB73330 is specially designed for 1 to 4 lithium ion/lithium polymer batteries and single or 2 lead-acid batteries. It integrates advanced functions such as high-precision voltage and current regulation, intelligent charging status indication and multiple protection mechanisms, and is widely used in handheld devices, mobile instruments, chargers and other scenarios. This article will deeply analyze the technical characteristics, working principles and application advantages of the CXLB73330 to help engineers achieve more reliable and efficient battery management solutions.
Overview and main characteristics of 1. chip
The CXLB73330 is packaged in a MSOP-10 package, with a high-efficiency PWM control mechanism, a switching frequency of 600kHz, a wide input voltage range, and a maximum withstand voltage of 20V. The charging process is divided into three stages: pre-charging (Pre-charge), constant current charging (CC) and constant voltage charging (CV), which can effectively extend battery life and improve charging efficiency.
The chip has the following outstanding features:
· High precision voltage controlCharging voltage accuracy of ± 0.5%, support multiple types of battery configuration;
· 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: Drive LED through STAT1 and STAT2 pins to display the charging status in real time;
· Wide temperature working range:-20 ℃ to 70 ℃, suitable for all kinds of harsh environment.
In addition, the CXLB73330 also provides a variety of models, including B/C/D/F versions for different battery numbers, to meet a variety of design requirements.
2. Pin Functions and Typical Application Circuits
The 10 pins of the CXLB73330 perform their respective duties to form a complete charging management system:
· STAT1/STAT2: Charging state indication output;
· VCC: Power input;
· GATE: Switch drive output;
· GND: simulation ground;
· NTC: External temperature detection;
· 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 current and voltage are set through an external resistor, and the temperature monitoring is realized with the NTC thermistor to ensure the safe and reliable charging process.
3. charging process and intelligent management
The charging process of the CXLB73330 is divided into three stages:
3.1. Pre-charge phase: When the battery voltage is lower than the set threshold, 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.
3.4. Work flow diagram
3.5. Charging process
3.6. Battery detection
In the absence of the battery, the voltage of the BAT pin will continue to flip between 0 and VOVP until a new battery is inserted.
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 pre-charge and cut-off current are set in proportion, such as 40% and 10% constant current values for lithium batteries.
4.2. Voltage Trim
Through the VTRIM pin external resistor, the constant voltage output value can be fine-tuned. For example, for dual lithium batteries:
where R = 40kΩ.
Measure the voltage value VCV of the constant voltage output, trim the VCV upward, and trim the resistor R
TRIM is connected between VTRIM pin and ground. Micro VCV down
Connect the trimming resistor RTRIM between the VTRIM pin and the BAT pin. Resistance RTRI
M resistance size formula is:
4.3. Temperature detection and protection
An external NTC thermistor enables temperature monitoring. When the temperature exceeds the set range, the charging is suspended until the temperature returns to normal.
CXLB73330 an external NTC thermistor to ground, monitor the battery temperature and abort charging when the temperature is outside the threshold. When the NTC pin voltage is
Below 200mV at high temperature or above 1.23V at low temperature, the CXLB73330 will suspend charging and the internal clock will stop timing. When the NTC detects
Press back to normal range, continue charging and resume timing. The NTC thermistor should be placed in close proximity to the battery packaging.
Cancel the battery temperature detection function, only need to ground the NTC pin.
4.4. Sleep mode
Remove input power to enter sleep mode. When the VCC voltage is lower than the UVLO threshold, or VCC is lower than VBAT 250mV, the CXLB73330 enters the sleep mode
The battery discharge current is minimized.
4.5. Charge cut-off current
In the constant voltage phase, the voltage drop of the charging current across the RSNS resistor is reduced to VITERM, and the EOC signal is generated inside the CXLB73330, and the charging is cut off.
At the same time, when the voltage drop of the charging current across the RSNS resistor is twice that of VITERM, a TAPE signal will be generated inside the chip. If
After half an hour the charging current still hasn't dropped to VITERM, charging is off.
4.6. Charging voltage setting
The battery voltage detects the voltage difference between the BAT and GND pins.
For lithium batteries, enter the short-circuit current detection mode when the voltage of each battery is lower than 2V; enter the pre-charge mode when the voltage of each battery is lower than 3V.
Electric mode; the charging cut-off voltage of each battery is 4.2V. After charging is completed, if each battery drops below 4.1V due to current leakage
Enter the recharge cycle.
For lead-acid batteries, when the voltage of a single battery is lower than 2.8V and the voltage of a double battery is lower than 3.2V, it enters the short-circuit current detection mode; when each battery
When the voltage is lower than 5.2V, it enters the pre-charge mode; the charging cut-off voltage of each battery is 7.2V. After charging is completed, if each battery is
When the flow leakage drops below 6.4V, the recharge cycle is entered.
4.7. Charging state indication
4.8. Timeout error recovery.
As illustrated by the workflow diagram, the CXLB73330 provides a recovery mechanism for charge timeout errors, including pre-charge timeouts and total charge time timeouts. Summary
As follows:
Case 1: The VBAT voltage is greater than the recharge threshold voltage and a timeout error occurs.
Recovery mechanism: The battery detection voltage drops to the recharge threshold voltage due to the battery discharging to the load, self-discharging or battery removal
Next, at this time, the CXLB73330 clears the error state and enters the no battery detection process. In addition, a power-on reset can clear this timeout error
Error status.
Case 2: The VBAT voltage is lower than the recharge threshold voltage and a timeout error occurs.
Recovery mechanism: When this happens, the CXLB73330 enables a IDETECT current. This small current can be used to detect the presence or absence of the battery. Only
This current is maintained until the battery voltage is lower than the recharge voltage. If the battery voltage is higher than the recharge voltage, the CXLB73330 is canceled
IDETECT the current and perform the recovery mechanism of case 1. Once the battery voltage is lower than the recharge threshold voltage, the CXLB73330 clears the timeout.
error, and enter the no battery detection process. A power-on reset can also clear this timeout error condition.
4.9. Output overvoltage protection
CXLB73330 built-in overvoltage protection. When the battery voltage is too high, such as the overvoltage generated when the battery is suddenly removed, this function can protect
protect the device itself and other components. When an overvoltage is detected, the function immediately turns off the PWM and indicates an error. When the battery voltage is lower than the charge
When the electrical threshold voltage, the error is released.
5. Protection Mechanism and Fault Handling
CXLB73330 integrated protection features:
· 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 150 ℃ overheat protection to prevent chip damage;
· Timeout RecoverySupport intelligent recovery mechanism for pre-charge and total charge timeout errors.
6. working conditions and electrical characteristics
6.1. Recommended working conditions
7. Packaging and Supply Chain Support
The CXLB73330 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.
EightConclusion
CXLB73330 with its high integration, high precision and multiple protection functions, become the ideal choice for multi-cell battery charge management. Whether it is a lithium battery or a lead-acid battery system, 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 to inject strong power into your next product.
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