CXLB73320 is an integrated circuit with constant current/constant voltage charging management function, which is suitable for single-section lithium iron phosphate battery. The chip integrated power transistor, without external current detection resistor and blocking diode, greatly simplifies the peripheral circuit design. Its input voltage range is 4.0V to 9.0V, supports a programmable charging current of up to 1A, and has multiple protection mechanisms, such as reverse connection protection, temperature monitoring, sleep mode, etc., to ensure safe and reliable charging process.
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[ CXLB73320 ]"
CXLB73320 lithium iron phosphate battery charging management IC details
In today's applications such as portable devices and mine lighting, lithium iron phosphate batteries are favored for their high safety, long life and stable performance. The design of efficient and reliable charge management circuits for such batteries has become the focus of engineers. As a linear charge management integrated circuit designed for a single-cell lithium iron phosphate battery, the CXLB73320 integrates a number of advanced functions and is suitable for various compact electronic devices. This article will analyze the characteristics, working principle, typical applications and design considerations of the CXLB73320 in depth, helping engineers to better select the chip and improve system performance.
First, product overview
CXLB73320 is an integrated circuit with constant current/constant voltage charging management function, which is suitable for single-section lithium iron phosphate battery. The chip integrated power transistor, without external current detection resistor and blocking diode, greatly simplifies the peripheral circuit design. Its input voltage range is 4.0V to 9.0V, supports a programmable charging current of up to 1A, and has multiple protection mechanisms, such as reverse connection protection, temperature monitoring, sleep mode, etc., to ensure safe and reliable charging process.
Main characteristics
· Reverse connection protection function: Effectively prevent damage caused by reverse connection of positive and negative electrodes of the battery.
· Built-in power tubeNo external discrete components, saving space and cost.
Adjustable constant voltage charging voltage: The default is 3.6V, which supports adjustment by external resistor.
· Multi-mode charging management: Support pre-charging, constant current charging, constant voltage charging and constant temperature control.
· Low power sleep mode: Automatically enter the sleep state when the input voltage is powered down, and the battery current consumption is less than 3μA.
· Dual state indication output: CHRG and DONE pins indicate the charging state and end state respectively.
· Automatic recharge function: Automatically restart the charging cycle after the battery voltage drops.
· Environmental protection package: SOP8 lead-free package, RoHS compliant.
Second, the typical application circuit
The typical application circuit of the CXLB73320 is very simple. Complete charging management can be realized by connecting the VIN pin to the input power supply and connecting the 10μF capacitor in parallel, connecting the BAT pin to the battery and connecting the 10μF capacitor in parallel, and connecting the PROG pin to the set resistor (e.g. 1.2kΩ corresponds to 1A charging). If the constant voltage charging voltage needs to be adjusted, a resistor Ri can be connected between FB and BAT. At this time, the positive voltage of the battery is:
where the unit of Ri is kΩ.
Three, detailed explanation of the working principle
The charging process of the CXLB73320 is divided into three stages:
3.1. Pre-charge phase: When the battery voltage is lower than 2.0V, the chip performs small current pre-charging with 10% current in constant current mode to activate the deeply discharged battery.
3.2. Constant current charging stage: After the battery voltage exceeds 2.0V, enter the constant current charging mode, and the current is set by the external resistor of the PROG pin:
ibat = rprog 1150 (ma)
3.3. Constant voltage charging phase: When the battery voltage is close to the set value, the current gradually decreases and enters the constant voltage mode. When the current drops to 10% of the constant current value, charging ends and the DONE pin outputs a low level.
Four, design considerations
· PCB Layout: PROG resistor should be close to the chip, bypass capacitors of VIN and BAT should be close to the pins, and the copper area of GND pin should be as large as possible to enhance heat dissipation.
· Thermal Management: The chip has a temperature adjustment function, which automatically reduces the current when the junction temperature exceeds 90°C to ensure system safety.
· Stability: The external capacitor of PROG pin should not be too large. It is recommended that the pole frequency be higher than 200kHz.
· Battery reverse connection protection: When the chip is connected in reverse, it enters the protection state and automatically recovers after removing the battery.
Five, the application field
CXLB73320 is widely used in:
· Miner's lamp and portable lighting equipment
· Lithium iron phosphate battery charger
· Various types of portable electronic equipment power management
Six, pin function and typical circuit
Seven, the conclusion
With its high integration, flexible programmability and comprehensive protection mechanism, CXLB73320 is an ideal choice for single-section lithium iron phosphate battery charging management. Whether it is a miner's lamp, emergency power supply or all kinds of portable devices, the chip can provide efficient and safe charging solutions. For more technical details or to buy samples, welcome to visitJTM-IC official website.
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