The MP2639B is a highly integrated, flexible switch-mode battery charging management device for a single-cell Li-ion and Li-Polymer battery used in a wide range of portable applications. The MP2639B works in three modes: charge mode, discharge mode and sleep mode. When the input power supply is available, the MP2639B operates as a switching charger to charge a 1S battery from a wide input power range of 5V to 16V, which can cover a USB PD voltage level. The MP2639B automatically detects the battery voltage and charges the battery in three phases: pre-charge, constant charge and constant voltage charge. Other features include charge termination and auto-recharge. When the input is absent, the MP2639B can provide a wide boost voltage to IN by adjusting the feedback voltage at FB. When working with the PD controller, the MP2639B can support a USB PD standard output voltage level.