Patent ID: 7642750

Claim:
A circuit for charging and discharging a battery, comprising: a first MOSFET having a first body diode and coupled to said battery for controlling discharging of said battery; a second MOSFET having a second body diode and coupled to said first MOSFET in series for controlling charging of said battery, wherein said first body diode of said first MOSFET and said second body diode of said second MOSFET are coupled in opposite directions; a load coupled to a common node between said first and second MOSFETs and coupled to said battery such that power in said battery is delivered to said load when said first MOSFET is turned on and said second MOSFET is turned off; and a controller coupled to gates of said first and second MOSFETs, and coupled to said common node, wherein said controller senses a current through said first MOSFET during said charging and during said discharging by sensing a drain voltage of said first MOSFET and a source voltage of said first MOSFET, and compares said current to a predetermined threshold, wherein if said current fails to satisfy said threshold then said current is adjusted under control of said controller.