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 chargable either through a first interface or through an AC-DC conversion circuit, said circuit comprising:

• a first buck/boost converter having a Switched Mode Power Supply (SMPS) mode which is configured to be controlled either in a buck or a boost mode, said first buck/boost controller being associated with a first external coil for embodying a battery charging circuit where a battery is chargable through a first interface (USB),
• a second buck/boost converter having a Switched Mode Power Supply (SMPS) mode configured to be controlled either in a buck or a boost mode, said second buck/boost controller being associated with a second external coil for embodying a second battery charging circuit where said battery is chargable through an AC/DC interface;
• by-pass circuit for performing a by-pass of either the voltage of said battery or of the voltage generated by said buck/boost controllers when in boost mode to a second interface (SIM/MMC), controlled by a control signal;
• and
• control circuit for controlling the Switched Mode Power Supply (SMPS) mode of said first and second buck/boost controller and for controlling said by-pass means so as to generate a converted voltage to said second interface.

A portable terminal equipment comprising a power management circuit including an internal battery which can be charged either through a USB interface or an AC/DC interface, said power management circuit comprising:

• a first buck/boost converter having a Switched Mode Power Supply (SMPS) mode configured to be controlled either in a buck or a boost mode, said first buck/boost controller being associated with a first external coil for embodying a battery charging circuit where a battery is chargeable through a first interface (USB),
• a second buck/boost converter having a Switched Mode Power Supply (SMPS) mode configured to be controlled either in a buck or a boost mode, said second buck/boost controller being associated with a second external coil for embodying a second battery charging circuit where said battery is chargeable through an AC/DC interface;
• by-pass circuit for performing a by-pass of either the voltage of said battery or the voltage generated by said buck/boost controllers when in boost mode to a second interface (SIM/MMC), controlled by a control signal;
• and
• controlling circuit for controlling the Switched Mode Power Supply (SMPS) mode of said first and second buck/boost controller and also for controlling said by-pass means so as to generate a converted voltage to said second interface.

A method for generating the power management of a portable electronic device comprising an internal battery chargeable either through a USB interface or through an AC/DC interface, said method comprising the steps of:

• arranging a first buck/boost converter associated with a first external coil for embodying a battery charging circuit where a battery is chargeable through an USB interface, said buck/boost converter also achieves a DC/DC up voltage conversion for converting the voltage from the battery to said USB interface so as to supply current to a peripheral unit connected to said USB interface;
• arranging a second buck converter associated with a second external coil for embodying a second battery charging circuit where said battery is chargeable through an AC/DC interface;
• arranging said second buck converter so as to perform boost conversion of the voltage of the battery to generate a higher voltage;
• by-passing the voltage of the battery, or the voltage generated by one of the two buck/boost converters controlled by a control signal;
• sensing the voltage of the battery as well as the voltage appearing from said USB interface and said AC/DC interface;
• and
• generating said control signal in response to said sensing step to bypass the higher voltage to said second interface.