The cxlb7209 can use the PWM Buck mode charge management integrated circuit powered by solar cells, with the function of tracking the maximum power point of solar cells. The cxlb7209 is very suitable for the charge management of single or multiple lithium batteries or lithium iron phosphate batteries. It has the advantages of small package, few peripheral components and simple use. The cxlb7209 has constant current and voltage charging mode, which is very suitable for lithium battery or lithium iron phosphate battery. In the constant voltage charging mode, the constant voltage charging voltage is set by the external resistance partial voltage network; in the constant current charging mode, the charging current is set by an external resistance. For deeply discharged batteries, when the battery voltage is lower than 66.7% of the set constant voltage charging voltage, cxlb7209 uses 15% of the set constant current charging current to trickle charge the battery. In the stage of constant voltage charging, the charging current decreases gradually. When the charging current decreases to 9.5% of the set constant current charging current, the state of charging end is entered. When the input power supply is powered down or the input voltage is lower than the battery voltage, the cxlb7209 automatically enters the sleep mode of low power consumption. Other functions include input low voltage latch, battery temperature monitoring, battery terminal overvoltage protection and charging status indication