Patent ID: 6014030
Filing Date: 2000-01-11
Classification: G01R

Abstract:
A circuit for monitoring current level magnitudes, polarity, or both associated with the charging and discharging of a battery having a positive terminal and a negative terminal, wherein the circuit acts as a switch for interrupting battery current when the battery current exceeds preset levels, the circuit comprising:a. a first power transistor having a first turn-on resistance, wherein said first power resistor is coupled to the positive terminal of the battery;b. a second power transistor having a second turn-on resistance, wherein said second power transistor is coupled between said first power transistor and the negative terminal of the battery;c. a first coarse comparator having a first input coupled between said first power transistor and the positive terminal and a second input coupled between said second power transistor and the negative terminal;d. a second coarse comparator having a first input coupled between said second power transistor and the negative terminal and a second input coupled between said first power transistor and the positive terminal; ande. a fine comparator activated by an output of either of said first coarse comparator and said second coarse comparator, said fine comparator having a first input coupled to a first resistance terminal of a resistive element and a second input coupled to a second resistance terminal of said resistive element, wherein an output of said fine comparator controls operation of said first power transistor and said second power transistor.