Patent ID: 7394223

Claim:
A protection circuit implemented on a single chip integrated circuit for protecting a battery operating at a set operating voltage, comprising: a primary input on the single chip integrated circuit for receiving an input voltage at a level above the set operating voltage; an output on the single chip integrated circuit for driving a voltage translating circuit that is operable to lower the input voltage level to the set operating voltage level; an input over voltage protection circuit for detecting an input over voltage condition wherein the input voltage applied to the primary input exceeds a predetermined input voltage limit and generating an input over voltage control signal responsive thereto; and a battery over voltage protection circuit for detecting a battery over voltage condition wherein a battery input voltage applied to the battery exceeds the set operating voltage by a predetermined battery over voltage limit and generating a battery over voltage control signal responsive thereto; a switch connecting said primary input to said output, wherein said switch is responsive to the input over voltage control signal for controlling said switch to disconnect the primary input from the output when the input voltage limit is exceeded by the input voltage and further wherein said switch is also responsive to the battery over voltage control signal for controlling said switch to disconnect the primary input from the output when such battery over voltage limit is exceeded by the battery input voltage.