US Patent 9952728 Device and method for measuring capacitance difference

A driving signal is outputted to each of the first and second capacitors in a measurement period so that voltage changes occur at the first and second capacitors. First and second modulating voltage signals are provided for the first and the second capacitors in the measurement period. An output signal in a first state or a second state according to a voltage difference between the first and second capacitors is generated. One of the voltage values of the first and second modulating voltage is automatically adjusted according to the output signal. A characteristic value for indicating a capacitance difference between the first capacitor and the second capacitor, which correlates to a length of time from a start point of the measurement period to a specified point that a condition change of the output signal occurs or a slope of the first or second modulating voltage signal, is generated.