Patent ID: 7791314

Claim:
A power supply topology comprising: a first path configured to be coupled to a controllable DC power source; a second path configured to be coupled to a rechargeable battery; a third path configured to be coupled to a system load, wherein said first, second, and third paths are coupled to a common node; a unidirectional switch coupled to said first path to allow selective coupling of said controllable DC power source to said system load via said common node; a selectively unidirectional switch coupled to said second path to allow selective coupling of said battery to said common node; and a power management control circuit configured to monitor the voltage of said battery and control the output voltage of said controllable DC power source to be within a selected tolerance range of said voltage of said battery, said power management control circuit including a wake up circuit having a comparison circuit configured to receive a first signal representative of a charging current level provided to said rechargeable battery via a fourth path and a second programmable signal representative of a predetermined wake up current level and to provide a comparison output signal in response to said first and second signals, said wake up circuit further including an output decision circuit configured to receive at least said comparison output signal and a selector signal from a selector circuit, said output decision circuit is configured to provide one of said comparison output signal or said selector signal to said selectively unidirectional switch to control the charging current level provided to said rechargeable battery by controlling the state of said selectively unidirectional switch, said selectively unidirectional switch is responsive to said comparison output signal to enter an intermediate conduction state to provide a current level to said battery representative of said predetermined wake up current level.