CXLB73309 is a highly integrated buck-boost charging management chip with built-in synchronous Buck-Boost architecture and low on-resistance power MOSFET driver, supporting a wide input voltage range of 4.5V ~ 25V and a maximum output power of 30W. Its uniqueness lies in the integration of PD3.0 and DPDM fast charging protocol identification function, can automatically adapt to all kinds of fast charging adapter, to achieve "plug and play" efficient charging experience.
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[ CXLB73309 ]"
CXLB73309: Integrated PD3.0 fast charge 30W intelligent buck charging management chip
With the rapid development of fast charging technology and the popularity of multi-string lithium battery applications, the market has put forward higher requirements for high-efficiency, high-integration, and intelligent charging management chips. As a synchronous buck-boost charging chip integrating PD3.0 and DPDM fast charging protocols, CXLB73309 not only supports flexible configuration of 2-5 strings of lithium batteries, but also has 30W maximum charging power and comprehensive intelligent management functions. It is suitable for high-power sound boxes, electric tools and other high-demand scenarios. This article will analyze the technical highlights, working principles and design practices of the CXLB73309 in depth to help developers build the next generation of high-performance charging systems.
Overview and Core Value of 1. Chip
CXLB73309 is a highly integrated buck-boost charging management chip with built-in synchronous Buck-Boost architecture and low on-resistance power MOSFET driver, supporting a wide input voltage range of 4.5V ~ 25V and a maximum output power of 30W. Its uniqueness lies in the integration of PD3.0 and DPDM fast charging protocol identification function, can automatically adapt to all kinds of fast charging adapter, to achieve "plug and play" efficient charging experience.
Core features include:
· Integrated PD3.0 UFP and DPDM fast charging protocol, support Type-C port intelligent identification;
· Support 2/3/4/5 series of lithium batteries, the battery type can be ternary lithium (4.2V) or lithium iron phosphate (3.65V);
· The maximum charging power is 30W, and the charging efficiency is up to 95%;
· Built-in 14-bit high-precision ADC, real-time monitoring of voltage, current and temperature;
· Standby power consumption as low as 5μA, support automatic wake-up and EN reset;
· Comprehensive protection mechanism: input overvoltage/undervoltage, battery overcharge/overcurrent, IC over temperature, NTC temperature protection;
· ESD 4kV, input pin withstand voltage 30V, excellent reliability;
· Small QFN5x5-32 package for compact design.
2. System Architecture and Electrical Performance
The CXLB73309 uses a fully integrated H-bridge Buck-Boost architecture, built-in dual current sampling (input and battery), bootstrap drive circuit and multiple LDO, to achieve high efficiency, low noise power conversion. Its switching frequency is fixed at 400kHz, taking into account the conversion efficiency and the volume of peripheral components.
Key electrical parameters:
· Input voltage range: 4.5V-25V;
· Battery voltage range: up to 32V;
· Charging current: adaptive according to the input voltage, up to 3A;
· Constant voltage accuracy: 1% (support N× 4.20V or N× 3.65V);
· Working temperature:-40 ℃ to 85 ℃.
3. intelligent charging management and protocol support
3.1. Three-stage charging process
CXLB73309 using the classicCurrent elimination-constant current-constant voltageCharging management:
· current elimination charging: When the battery voltage is <2.5V, it is activated with a small current of 50mA;
· constant current charging: Fast charging at the set current after the voltage is normal;
· constant voltage charging: When approaching full voltage, it turns to constant voltage, and the current gradually drops below 100mA to stop charging.
3.2. Fast-charge protocol adaptation.
The chip has built-in PD3.0 and DPDM protocol analysis module, which can automatically identify the adapter capability and apply for the optimal voltage (such as 5V/9V/12V/15V/20V). If the adapter power is insufficient, the system will automatically limit the charging current to avoid the input drop.
3.3. Power and battery configuration
· Maximum power setting: Set 20W or 30W power through PSET pin external resistor;
· Battery string number setting: Set 2/3/4/5 series of batteries through BAT_NUM pin resistance;
· Battery Type Selection: Same pin compatible with device type selection (ternary lithium/lithium iron).
4. Temperature Protection and NTC Intelligent Monitoring
CXLB73309 integrated high-precision NTC detection circuit, through the external thermistor real-time monitoring of battery temperature. its adoptionDual current source switching technology(80 μA/20 μA) to broaden the detection range and improve accuracy:
· High temperature threshold: ≥ 45 ℃, stop charging;
· Low temperature threshold: ≤ 0 ℃, stop charging;
· Built-in thermal shutdown: 125 ℃ (hysteresis 40 ℃).
If the scheme does not need NTC function, it is necessary to connect 10kΩ resistor to NTC pin, and floating is strictly prohibited.
5. Status Indication and Low Power Management
5.1. Indicator light configuration
Chip SupportDouble lamp or single lampDisplay mode:
· Dual lamp mode: D1 charging light, D2 full light, fault double flash;
· Single lamp mode: Blinking means charging, always on means full, flashing means fault.
5.2. Low power consumption and wake-up
· Automatically enter after unplugging the charger5μA standby mode;
· Support EN pin high level pulse (>200ms) wake up;
· EN lasts high for 10 seconds to trigger a system reset.
6. PCB Design and Component Selection Recommendations
To ensure system stability and thermal performance, it is recommended that:
· The input/output capacitor is as close as possible to the chip pin, and the low ESR ceramic capacitor is selected;
· 1% current sampling resistor, low temperature drift metal film resistor;
· The power inductance is recommended to be above 4.7 μH/8A, and RDC<10mΩ;
· The grounding copper sheet shall be expanded as much as possible, and the bottom pad of QFN shall be fully grounded to facilitate heat dissipation.
7. typical application scenarios
CXLB73309 widely applicable:
· high power bluetooth speaker: Support multiple strings of batteries, longer life;
· Electric toolsHigh voltage, high current, adapt to fast charge and discharge;
· Industrial Handheld Devices: Wide temperature operation, high reliability;
· USB PD mobile power: Compatible with mainstream fast charging protocols;
· Smart Home Energy Storage Equipment: Supports lithium iron/ternary lithium battery system.
8.Package and pin function
Nine,Typical Application Schematic
10. epilogue
With its high integration, intelligent fast charge identification and comprehensive protection functions, the CXLB73309 provides an efficient, safe and flexible solution for multi-string lithium battery charging system. Whether it is consumer electronics or industrial and tool products, the chip can help developers build competitive power systems. For more information about CXLB73309 technical information, sample application or purchase information, please visitJTM-IC official website, we will provide you with professional technical support and high-quality service.
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