CXLB73310 is a fully integrated buck-boost charge management IC with built-in 4-switch MOSFET, current detection circuit and loop compensation, which greatly simplifies the peripheral design. Its input voltage range is as wide as 3.6V-21V,BAT terminal withstand voltage is as high as 30V, supports maximum 3A charging current, and can be flexibly adjusted through external resistors.
-
[ CXLB73310 ]"
CXLB73310: intelligent fast charge buck charging chip, fully support 1-5 string lithium battery applications
With the rapid development of portable electronic devices, efficient, flexible and safe battery charging management scheme has become the core requirement of product design. As a highly integrated switch-mode buck-boost charging management chip, CXLB73310 not only supports 1-4 lithium ion/polymer batteries and 1-5 lithium iron phosphate batteries, but also has the ability to apply for 3A high current charging and automatic fast charging protocol. It can be widely used in multiple scenes such as Bluetooth speakers, electric tools, walkie-talkies, etc. This article will comprehensively analyze the technical characteristics, design points and typical applications of the CXLB73310 to help engineers build a high-performance charging system.
1. chip overview and core advantages
CXLB73310 is a fully integrated buck-boost charge management IC with built-in 4-switch MOSFET, current detection circuit and loop compensation, which greatly simplifies the peripheral design. Its input voltage range is as wide as 3.6V-21V,BAT terminal withstand voltage is as high as 30V, supports maximum 3A charging current, and can be flexibly adjusted through external resistors.
Core features include:
· Fully integrated switch mode buck-boost architecture with excellent efficiency;
· Support 1-4 strings of lithium ion/polymer batteries and 1-5 strings of lithium iron phosphate batteries;
· Maximum 3A charging current, charging current can be set by external resistor;
· Automatic fast charging protocol application, support 9V/12V input;
· Built-in NTC temperature protection and input current adaptive function;
· 500kHz switching frequency, taking into account the efficiency and EMI performance;
· Perfect protection mechanism: input overvoltage/undervoltage, output short circuit, chip over temperature, etc;
· TSSOP20-PP package, excellent heat dissipation, suitable for compact design.
2. System Architecture and Electrical Performance
The CXLB73310 adopts synchronous Buck-Boost architecture, integrates high-side and low-side power MOSFET drivers, and supports BST bootstrap power supply. Its fixed 500kHz switching frequency effectively reduces the volume of inductors and capacitors and improves the system power density.
Key electrical parameters:
· Input voltage: 3.6V-21V;
· Battery voltage: maximum 30V;
· Charging current: maximum 3A, can be set by RS resistor;
· Constant voltage accuracy: VFB = 1V ± 1%;
· Quiescent current: 0.7mA (typical);
· Turn-off current: 50μA;
· Working temperature:-40 ℃ to 125 ℃.
3. intelligent charging management and protection mechanism
3.1. Three-stage charging process
CXLB73310 adopt a completeCurrent elimination-constant current-constant voltageCharging management:
· current elimination charging: When the battery voltage is <0.25 ×VCV, it is activated with a small current (10% ICC);
· constant current charging: Fast charging at the set current after the voltage is normal;
· constant voltage charging: Turn to constant voltage when approaching the set voltage, and stop charging when the current gradually drops to 10% ICC.
3.2. Input current adaptive
The chip realizes the input voltage limiting function through the VSEN pin to avoid the adapter overload. Its modulation voltage is 1V, and the minimum input voltage threshold can be set through external resistors RA1 and RA2:
If VSENTo VINThis function is disabled, and charging is prohibited by grounding.
3.3. Comprehensive protection function
· Input overvoltage/undervoltage protection：OVP=23V，UVP=3.6V；
· Battery overvoltage/short circuit protection：OVFB=1.07×VCV，VSHORT=0.25×VCV；
· NTC temperature protection: Support external thermistor, low temperature/high temperature point can be set;
· Charging timeout protection: TC phase ≤ 2 hours, CC/CV phase ≤ 20 hours;
· Chip over-temperature protection: 120 ℃ start adjustment, 150 ℃ shutdown (hysteresis 40 ℃).
4. Critical Circuit Design Guide
4.1. Charging current setting
The constant current charging current ICC is set by the detection resistor RS:
For example, to set a charging current of 2A, select RS = 25mΩ and pay attention to its power rating (≥ 0.2W is recommended).
4.2. Floating voltage setting
The battery float voltage VCV is set by external voltage dividing resistors RFB1 and RFB2 of FB pin:
It is recommended to use a 1% precision resistor to ensure voltage accuracy.
4.3. NTC protection configuration
The chip supports external NTC resistors for temperature protection, and high/low temperature thresholds can be set independently by RUP and RCONV. If the NTC function is not required, the NTC pin must be grounded.
4.4. Status indication
The STAT pin supports LED status display:
· Charging: Low level, LED is always on;
· Full: High resistance state, LED off;
· Fault: 1.5Hz flicker;
· No battery: Flashes off.
5. PCB Layout and Thermal Recommendations
To ensure system stability and thermal performance, it is recommended that:
· The saturation current of power inductor L1 shall be left with margin, and it is recommended to be ≥ 6A;
· The current detection resistor RS should be close to its two end taps to avoid introducing noise;
· Input/output capacitors as close as possible to the chip pin layout;
· The thermal pad at the bottom of the chip should be fully connected to the PCB ground plane to improve heat dissipation.
6. typical application scenarios
CXLB73310 widely applicable:
· bluetooth speaker: Support multiple strings of batteries, longer life;
· Electric toolsHigh voltage, high current, adapt to fast charge and discharge;
· Electronic Cigarette EquipmentAccurate voltage and temperature control;
· Walkie-talkie and industrial handheld equipment: Wide temperature operation, high reliability;
· Lithium iron phosphate battery pack: Support 1-5 string flexible configuration;
· Smart Toys: Integrated protection, safe and reliable.
7.Package and pin function
Eight, typical application schematic diagram
(1) The saturation current value of L1 power inductor shall be carefully confirmed and sufficient margin shall be reserved.
(2) The power resistor R is used to set the charging current value and must be tapped against its two ends.
(3) The BAT tap of the power resistor R is close to its patch capacitor, and the other patch capacitors are as close as possible to the chip pin layout.
(4) The EN pin of the chip is a low-voltage pin with a 500KQ pull-down resistor inside.
(5) The battery voltage line of the chip connected to the FB pin must be sampled from the real anode of the battery as much as possible to reduce the line loss error.
(6) When the DM and DP pins in the figure are not in use, they are directly suspended.
(7) The red solid line in the figure shows the current flow path.
9. epilogue
With its high integration, flexible battery configuration, intelligent fast charging identification and comprehensive protection functions, the CXLB73310 provides an efficient, safe and compact solution for multi-string lithium battery charging system. Whether in consumer electronics or industrial applications, the chip can help developers build competitive power systems. For more information about CXLB73310 technical information, sample application or purchase information, please visitJTM-IC official website, we will provide you with professional technical support and high-quality service.
Ten, the relevant chip selection guide download ► More similar products....
