Patent ID: 7755683

Claim:
A method of reading a capacitive pressure sensor comprising an array of pressure-sensing capacitors ordered in rows and columns functionally connected through row lines and through column lines substantially orthogonal to each other, using a biasing and reading circuit comprising column and row selectors, and a charge amplifier outputting a voltage of the pressure based capacitance of a selected pressure-sensing capacitor of the array, the method comprising: resetting an output voltage of the charge amplifier; connecting nonselected row and column lines of the array to a reference voltage while connecting one of an auxiliary capacitor and the selected pressure-sensing capacitor to an input of the amplifier while connecting the other one of the auxiliary capacitor and the selected pressure-sensing capacitor to define a feedback capacitor of the amplifier, the feedback capacitor being discharged by the connection of the nonselected row and column lines of the array to the reference voltage; and applying a step voltage on the one of the auxiliary capacitor and the selected pressure-sensing capacitor that is connected to the input of the amplifier and reading the output voltage at steady-state.