Integrated capacitive-sensor interface based on a multi-slope modulator

This paper presents an energy-efficient capacitive sensor interface based on a multi-slope analog-to-digital converter (ADC). The interface utilizes precision resistor and time as references. By using a multi-slope analog-to-digital converter, the conversion time of this multi-slope modulator is reduced down to 50us. The counter works as a sinc filter to reduce the noise, which helps to achieve a resolution of 14.5 bits for 250 Hz signal bandwidth.