| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a coulomb counter which reduces a circuit scale, impresses on an internal circuit the optimal voltage adapted to the purpose of the use so as to reduce power consumption and outputs counted values with few errors. Ž<P>SOLUTION: In the coulomb counter which outputs the counted value proportional to input voltage of a potential difference brought about at the opposite ends of a sense resistance, an A/D conversion circuit 30 and a logic circuit 10 are the principal parts of an IC part of the counter and an oscillation circuit 31 forms a clock signal for indicating the timing of an operation processing by the logic circuit 10. As to these circuits, first voltage 3 V lower than power supply voltage 5 V, which is generated by an internal power supply generating circuit 32 whereon the power supply voltage 5 V is impressed as an external power supply, is impressed on the A/D conversion circuit 30 and second voltage 1.8 V lower than the first voltage 3 V is impressed on the logic circuit 10, while third voltage 1.2 V lower than the second voltage 1.8 V is impressed on the oscillation circuit 31. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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