With the rapid development of mobile devices, portable energy storage and intelligent hardware, efficient, compact and multi-protocol compatible power management chips have become the core of product design. As a highly integrated two-way synchronous buck-boost charge and discharge management chip, CXLB73328 not only supports 45W input and output power, but also is compatible with PD3.1, AFC, FCP, QC and other mainstream fast charging protocols, and is suitable for 2-6 lithium batteries or lithium iron phosphate battery systems. This article will comprehensively introduce the functional characteristics, system structure, working mode and typical applications of the CXLB73328, helping engineers to achieve high-performance, highly integrated power supply design.
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[ CXLB73328 ]"
With the rapid development of mobile devices, portable energy storage and intelligent hardware, efficient, compact and multi-protocol compatible power management chips have become the core of product design. As a highly integrated two-way synchronous buck-boost charge and discharge management chip, CXLB73328 not only supports 45W input and output power, but also is compatible with PD3.1, AFC, FCP, QC and other mainstream fast charging protocols, and is suitable for 2-6 lithium batteries or lithium iron phosphate battery systems. This article will comprehensively introduce the functional characteristics, system structure, working mode and typical applications of the CXLB73328, helping engineers to achieve high-performance, highly integrated power supply design.
1. chip overview and core technology characteristics
CXLB73328 is a synchronous buck-boost controller with integrated power MOS and multi-protocol identification function. It has built-in complete Type-C PD3.1, AFC, FCP, QC2.0/3.0/3.0 and other fast charging protocols and supports USB-C and USB-A dual-port output. Its core features include:
· Support 2/3/4/5/6 series batteries, battery type and string number can be set by external resistor;
· Charge and discharge power up to 45W, charging efficiency up to 96.5;
· Built-in synchronous buck-boost power MOS, on-resistance as low as 7mΩ;
· Integrated 14-bit high-precision ADC, real-time monitoring of voltage, current and battery status;
· Support 4/2/1 LED power indication with multi-mode status display;
· Standby power consumption as low as 100 μA, support EN key wake-up and shutdown control;
· With input overvoltage/undervoltage, output overcurrent/short circuit, battery overcharge/overdischarge/overcurrent, IC over temperature and NTC temperature protection;
· QFN7 × 7-60 package, excellent heat dissipation, compact layout.
2. System Structure and Pin Function
The CXLB73328 integrates BUCK-BOOST controller, Type-C PD protocol module, multi-channel ADC, I2C interface and GPIO control circuit. Its key pins include:
· VBUS/VBUSG/VBUS_I: Type-C port input and output detection and path control;
· VIN/VING: USB-A port input and output detection and control;
· CSP1/CSN1、CSP2/CSN2Input and output current sampling;
· LX1/LX2: Buck-buck inductor connection node;
· BAT_P/BAT: Battery power and detection pin;
· CC1/CC2 、 dpc/dmc: Type-C protocol communication and fast charge identification;
· DPA1/DMA1: Quick charge identification of USB-A port;
· PSET, BAT_NUM, VSET: Used to set power, number of battery strings and battery type respectively;
· EN: enable and wake-up control, support short press, long press and double click operation.
3. charge and discharge management mechanism
3.1. Charging management
The CXLB73328 supports complete current elimination & rarr; constant current & rarr; constant voltage & rarr; cut-off & rarr; recharging process:
· current elimination charging: Pre-charge at about 50mA when the battery voltage is lower than 2.5V; Charge at about 200mA between 2.5V and current elimination threshold;
· constant current charging: After the battery voltage exceeds the current elimination threshold, charge quickly according to the set current;
· constant voltage charging: When the battery voltage is close to the set value, it turns to the constant voltage stage, and the current gradually decreases;
· Charge cut-off and recharging: Stop charging after the current is lower than 100mA and lasts for a certain period of time; automatically restart charging when the voltage drops.
The chip can automatically apply for the best voltage and current according to the charger type, and supports intelligent adaptation such as PD, AFC, FCP, etc.
3.2. Discharge management
In discharge mode, the CXLB73328 supports PD2.0/3.0/3.1, QC2.0/3.0/3.0, FCP, AFC, Apple 2.4A, BC1.2 and other output protocols. It has Try.SRC function and can be used as power output first. Its single-inductor architecture supports single-port fast-charging output, and automatically switches to normal charging mode when both ports are used at the same time.
4. System Configuration and Power Management
Key parameter settings are CXLB73328 via external resistors:
· PSET Pin: Set the maximum power of the system, support 20W ~ 45W multi-speed adjustable;
· BAT_NUM Pin: Set the number of batteries in series (2~6);
· VSET Pin: Set the full voltage of a single battery (3.65V ~ 4.4V);
· NTC Pin: Connect thermistor to realize temperature protection and support dynamic current switching detection.
5. working mode and state management
5.1. Light Load and Standby Management
· After no-load for 10 seconds, it will automatically enter a low-power state, and the standby current shall be less than or equal to 100 μA;
· Support button wake-up and automatic detection of charging and discharging equipment;
· Multi-port output, any port current is lower than 80mA for 16 seconds after the automatic shutdown;
· Single port output power below 350mW for 32 seconds after entering standby.
5.2. Charging and placing mode
Support the connection of power supply and equipment at the same time, give priority to the power supply of the equipment, and close the discharge path when the input voltage is higher than 5.6V to ensure safety. Automatically switch the working state when the power supply or device is plugged in, supporting smooth transition.
6. power display and user interaction
The chip supports multiple LED display modes:
· 4 lamp modes: Accurately display the power with 25% as the gear, and the charge and discharge status indication is clear;
· 2 lamp modes: Support two-color lamp and monochrome lamp configuration, adapt to different structural design;
· 1 Lamp mode: Indicates the status by flashing frequency, suitable for minimalist products.
The EN pin supports short press (power on/wake up), long press (reset), double click (shutdown) and other operations, and the user interaction is flexible and reliable.
7. comprehensive protection mechanisms
CXLB73328 with multiple security protections:
· Input overvoltage/undervoltage protection;
· Output overcurrent and short circuit protection;
· Battery overcharge, overdischarge, overcurrent protection;
· IC over-temperature protection (threshold 125 ℃, hysteresis 40 ℃);
· NTC temperature protection, support high and low temperature charging prohibition;
· ESD protection up to 4kV, key pin withstand voltage 30V.
8. typical application scenarios
CXLB73328 are ideal for the following applications:
· 45W mobile power supply and portable energy storage equipment;
· Multi-string lithium battery power tools and drones;
· Type-C/USB-A dual-port car charger;
· Industrial handheld devices and smart home power supply;
· Multi-protocol fast charging adapter and power module.
Key Points of 9. Design and BOM Suggestions
· inductance selection: Recommended 4.7 μH, 9A saturation current, low DCR power inductor;
· Capacitance Configuration: It is recommended to use 22μF MLCC in parallel with 100μF solid capacitor for input and output;
· sampling resistance: Use 0.005Ω high-precision, low-temperature drift metal film resistor;
· NTC Circuit: A 100nF capacitor should be arranged near the NTC pin, and a 10kΩ resistor should be connected to the ground when NTC is not used;
· EN pin: It must be connected to a 10kΩ pull-down resistor and cannot be suspended.
10. epilogue
With its high integration, multi-protocol compatibility, flexible power configuration and comprehensive system protection functions, the CXLB73328 provides an ideal single-chip solution for 45W bidirectional charge and discharge applications. Whether in consumer electronics or industrial-grade devices, the chip offers an excellent balance between performance, cost and reliability.
JTM-IC（jtm-ic.com) As a professional integrated circuit solution provider, we are committed to providing customers with high-performance, high-reliability chip products and complete technical support. If you need to obtain CXLB73328 samples, technical
For technical information or design assistance, please visit our official website or contact the technical support team.
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