Patent ID: 6856143

Claim:
An apparatus for measuring a capacitance comprising: a first set of p and n element-pairs coupled to a first conductor and operable to selectively charge and discharge the first conductor in response to a voltage potential applied to the first set of p and n element-pairs; a second set of p and n element-pairs coupled to a second conductor and operable to selectively charge and discharge the second conductor in response to a voltage potential applied to the second set of p and n element-pairs, wherein currents are measured at drains associated with the first set of p element-pairs as the conductors charge and discharge such that a capacitance associated with the first conductor is determined based on the currents at the drains; and a reference structure coupled to the first and second sets of p and n element-pairs and operable to provide a calibration element for measuring the capacitance associated with the first conductor.