Patent ID: 7876068

Claim:
A battery charge indicator for sensing and indicating various states of charge of a lithium ion battery, the battery charge indicator comprising: a current sensing circuit for sensing charging current to said lithium ion battery during a constant current mode of operation and a constant voltage mode of operation and providing a first charge indication signal based upon comparing the magnitude of said charging current with a first predetermined value and generating a first charge indication signal solely as a function of said charging current when said charging current is less than or equal to said first predetermined value, wherein said first predetermined value is representative of a first predetermined charge state representative of an initial state of charge of said lithium ion battery, said current sensing circuit providing a second charge indication signal based upon comparing the magnitude of said charging current with a second predetermined value and generating a second charge indication signal solely as a function of said charging current when said charging current is less than or equal to said second predetermined value, said current sensing circuit providing a third charge indication signal based upon comparing the magnitude of said charging current with a third predetermined value and generating a third charge indication signal in said constant voltage mode of operation solely as a function of said charging current when said charging current is less than or equal to said third predetermined value; a first indicator responsive to said first charge indication signal for providing an indication when said lithium ion battery is at an initial state of charge; a second indicator responsive to said second charge indication signal for providing an indication when said lithium ion battery is at a transitional state of charge; and a third indicator responsive to said third charge indication signal for providing an indication when said lithium ion battery is at a near full state of charge.