Patent ID: 7750604

Claim:
A battery charging circuit comprising: an alternating current (AC) to direct current (DC) converter operable for providing a charging power to a battery pack; a charging control switch coupled between said AC to DC converter and said battery pack operable for transferring said charging power to said battery pack in a continuous charging mode and a pulse charging mode; and a charger controller operable for generating a node voltage signal at a node and for providing a converter control signal to control an output of said AC to DC converter according to said node voltage signal, and for providing a switch control signal to control said charging control switch according to a status of said node voltage signal in said continuous charging mode and providing said switch control signal according to a pulse signal in said pulse charging mode, wherein said node senses a charging current of said battery pack to produce said node voltage signal if a battery voltage of said battery pack is lower than a predetermined battery voltage, and wherein said node senses said output of said AC to DC converter to produce said node voltage signal if said battery voltage reaches said predetermined battery voltage; and wherein said charger controller further comprises: a current error amplifier coupled to said node and operable for comparing said charging current of said battery pack with a predetermined charging current; and a voltage error amplifier coupled to said node and operable for comparing said output of said AC to DC converter with said predetermined battery voltage.