Patent ID: 7230435

Claim:
A capacitance measurement circuit comprising: first, second and third terminals, said first terminal being accompanied by a first capacitance including first and second capacitance components to be measured and a non-target capacitance component not to be measured, said third terminal being accompanied by a dummy capacitance operating as a dummy of said non-target capacitance component; a first current detector detecting a first current supplied to said first terminal; a second current detector detecting a second current induced from said second terminal; a third current detector detecting a third current supplied to said third terminal; a target capacitance forming section formed between said first terminal and said second terminal so that said first terminal is accompanied by said first capacitance component, said target capacitance forming section, said first to third terminals, and said first to third current detectors comprising a capacitance measurement section; and means coupled to the capacitance measurement section for providing a capacitance value of the second capacitance component by calculating the outputs of said first to third current detectors.