Abstract: An evaluation circuit, system, and method for evaluating a capacitive or inductive sensor includes first and second measurement connections to which sensors and/or reference elements are connected, first and second charging and discharging circuits that respectively output first and second charging and discharging signals to the first and second measurement connections. A comparator circuit compares the temporal behavior of the first and second charging and discharging signals. An integrator circuit produces an output voltage that changes as a function of the voltage at the output of the comparator circuit. The output voltage of the integrator circuit is connected to the first or second measurement connection to adjust the respective first or second charging and discharging signal. A measurement signal derived from the output voltage of the integrator circuit is a measure of impedance differences between the sensors or reference elements at the first and second measurement connections.

Abstract: An evaluation circuit, system, and method for evaluating a capacitive or inductive sensor includes first and second measurement connections to which sensors and/or reference elements are connected, first and second charging and discharging circuits that respectively output first and second charging and discharging signals to the first and second measurement connections. A comparator circuit compares the temporal behavior of the first and second charging and discharging signals. An integrator circuit produces an output voltage that changes as a function of the voltage at the output of the comparator circuit. The output voltage of the integrator circuit is connected to the first or second measurement connection to adjust the respective first or second charging and discharging signal. A measurement signal derived from the output voltage of the integrator circuit is a measure of impedance differences between the sensors or reference elements at the first and second measurement connections.