CXLB7321 is a perfect single chip lithium ion battery constant current / constant voltage linear power management chip, its SOT package and few peripheral components are very suitable for portable products, and CXLB7321 is specially designed for USB power supply specifications. Based on the internal MOSFET structure, there is no need for external induction resistance and blocking diode. When the external environment temperature is too high or working at high power, the thermal feedback can adjust the charging current to reduce the chip temperature. The charging voltage is limited to 4.2V, and the charging current can be adjusted by external resistance. When the charging current drops to 1 / 10 of the set value after reaching the predetermined charging voltage, the cxlb7321 automatically ends the charging process. When the input terminal (adapter or USB power supply) is unplugged, the cxlb7321 will automatically enter the low current state, and the battery leakage current will drop below 2 μ a. The cxlb7321 can also be set to stop working to reduce the power supply current to 25 μ a. Other features include: charging current monitoring, undervoltage locking, automatic recharging and status pins to show end of charge and presence of input voltage