Power management circuit for a portable electronic device including USB functionality and method for doing the same

A Power Management circuit for a portable electronic device comprising an internal battery (200) to be charged either through a first interface or through a AC-DC conversion circuit. The circuit comprises a first buck/boost converter (210) having a Switched Mode Power Supply (SMPS) mode which can be controlled either in a buck or a boost mode, said first buck/boost controller being associated with a first external coil (213) for the purpose of embodying a battery charging circuit through a first interface (USB). The circuit further comprises a second buck/boost converter (220) which can also be controlled either in a buck or a boost mode, the second circuit being also associated with a second external coil (223) for the purpose of embodying a second battery charging circuit through an AC/DC interface. Bypass circuits (230) are used for performing, under control of a control circuit (250) , the bypass of either the either the voltage of the battery or the voltage generated by said buck/boost controllers when in boost mode to a second interface (SIM/MMC). There is therefore achieved the possibility to generate, without requiring an additional coil and associated capacitor, OTG, = SIM/MMC interface while keeping the possibility of charging the battery.