CXLB73274 is a single lithium battery linear charging chip for space-limited portable devices. It supports an input operating voltage of 4.5V to 6.5V, has a rated withstand voltage of up to 30V, and has a 6.5V input overvoltage protection function, compatible with not voltage stabilizing adapter and USB power supply. The chip integrates complete charging management functions, including four stages: short circuit charging, pre-charging, constant current charging and constant voltage charging, with charging voltage accuracy of ± 1% and current accuracy of ± 10%, supports a minimum charging cut-off current of 1mA to meet the charging requirements of various small-capacity lithium batteries.
-
[ CXLB73274 ]"
In today's increasingly small and intelligent portable electronic devices, efficient, safe and small-volume battery management chips have become an indispensable part of product design. CXLB73274, as a highly integrated single lithium battery linear charger, is widely used in smart watches with its excellent input pressure resistance, high precision charging control and extremely low standby power consumption, bluetooth headphones and other space-and power-sensitive devices. This article will comprehensively analyze the technical characteristics, working modes and typical applications of CXLB73274, so as to help engineers better select the chip and enhance product competitiveness.
I. Product Overview
CXLB73274 is a single lithium battery linear charging chip for space-limited portable devices. It supports an input operating voltage of 4.5V to 6.5V, has a rated withstand voltage of up to 30V, and has a 6.5V input overvoltage protection function, compatible with not voltage stabilizing adapter and USB power supply. The chip integrates complete charging management functions, including four stages: short circuit charging, pre-charging, constant current charging and constant voltage charging, with charging voltage accuracy of ± 1% and current accuracy of ± 10%, supports a minimum charging cut-off current of 1mA to meet the charging requirements of various small-capacity lithium batteries.
II. Introduction to core features
2.1. High-precision charging management
CXLB73274 built-in high-precision voltage and current regulation loop, charging float-charge voltage preset to 4.2V, precision control within ± 1%. You can set the fast charging current through the external resistor (0.54kohm to 13.5 Kohm) of the ISET pin, ranging from 10mA to 250mA. In addition, version A supports setting precharge and termination current through PRE-TERM pins to flexibly handle different system load scenarios.
2.2. Comprehensive security protection mechanism
· Input overvoltage and undervoltage protection: When the input voltage exceeds 6.5V or less than 3.3V, the chip automatically enters the protection state.
· Temperature monitoring and regulation: Built-in JETTA standard temperature monitoring, supports NTC thermistor access, realizes full-speed charging in the range of 0 ℃ to 45 ℃, and automatically adjusts the current or stops charging when it exceeds the range.
· Short circuit and reverse connection protection: it has ISET and OUT short circuit detection functions to prevent abnormal working conditions from damaging chips or batteries.
· Thermal management mechanism: automatically adjust the charging current when the junction temperature exceeds 125 ℃, and turn off the output when 150 ℃ to ensure system safety.
2.3. Low power consumption and high reliability
In the no-load state, the chip static current is as low as 125μa, and the leakage current at the battery end does not exceed 75nA, which greatly prolongs the standby time of the device. The DFN2 * 2-8 package has a compact structure, and the bottom heat dissipation pad design effectively improves the thermal performance, which is suitable for high-density PCB layout.
3. Typical application scenarios
· Smart watch and bracelet: The small size and low power consumption of CXLB73274 are very suitable for wearing devices. It can be used while charging and improving user experience.
· Bluetooth headset and hearing aid equipment: its high-precision cut-off current and temperature protection function ensures that the earphone battery is full in a safe environment and prolongs its life.
· Low power handheld instrument: such as portable sensors and medical detection equipment, the chip can realize stable and reliable battery management in a limited space.
4. Pin function and model selection guide
CXLB73274 provides versions A and B. The main differences are:
·Version A (CXLB73274A): with PRE-TERM pins, you can customize the pre-charging and termination current.
·Version B (CXLB73274B): it has CHRG pin and provides LED indication function of charging status.
Users can select the corresponding model according to whether current programming or status indication is required. In the design process, it is recommended to arrange the input/output capacitors as close to the chip pins as possible, and the ISET resistor wiring should be short and straight to reduce noise interference.
V. Detailed explanation of working mode
CXLB73274 automatically switch operating modes under different conditions, including:
·Sleep mode: When the input voltage is between the battery voltage and the undervoltage lock threshold, the chip enters the low power state.
·Normal charging cycle: it covers four stages: short circuit charging, current elimination charging, constant current charging and constant voltage charging, and monitors the battery status throughout the process.
·TTDM (timer disabled mode): When the TS pin is pulled up or the battery is not connected, the chip pauses the timer and continuously detects the battery status, which facilitates the system to flexibly manage the charging process.
VI. Design attention
6.1. Layout suggestions: The input/output capacitor should be close to the chip pin. The high current path adopts a large area covered with copper, and the heat dissipation pad is connected to the ground plane through multiple vias.
6.2. Temperature detection: If the NTC function is not used, 10 kOhm resistor should be indirectly input in TS and GND to ensure the normal operation of the chip.
6.3. Current setting: for charging current lower than 50mA, it is recommended to add RC filter circuit to ISET pin to improve stability.
VII. Schematic diagram of typical application circuits
Eight, about JTM-IC
JTM-IC (official website:jtm-ic.com) is an enterprise focusing on the design and sales of high-performance power management chips, dedicated to providing stable and efficient integrated circuit solutions for global customers. To learn more about the technical information, sample application or purchase information of CXLB73274 series products, please visit our official website or contact the customer service team.
IX. Download the relevant chip selection guide -More similar products....
