Low voltage charge-balanced capacitance-voltage conversion circuit for one-side-electrode-type fluid-based inclination sensor

Low voltage detection circuit for capacitance sensor is important to connect low voltage digital circuit interface. We demonstrated two configuration types of charge-balanced capacitance-voltage (C-V) conversion circuit by using operational-amplifier (op-amp) and inverter-amplifier (inv-amp). These circuits were packaged with one-side-electrode-type fluid- based inclination sensor on ceramic substrate. Performances of these circuits were evaluated. This inclination sensor system could be combined with digital circuit by the inv- amp charge-balanced C-V conversion circuit at Vdd = 1.3 V.