Patent ID: 7595648
Filing Date: 2009-09-29
Classification: G01P

Abstract:
1. A read device of a capacitive sensor, comprising: modulated signal source structured to generate a modulated electrical read signal and supply said modulated electrical read signal to said capacitive sensor; a discrete-time sense circuit, connectable to said capacitive sensor, for generating a first electrical output signal, correlated to capacitance variations of said capacitive sensor, in response to variations of said electrical read signal; a demodulator stage, connected to said sense circuit, for demodulating said first electrical output signal and generating a demodulated second electrical output signal; and a low-pass filtering stage, connected to said demodulator stage, for generating a filtered third electrical output signal, on the basis of said second electrical output signal; and a phase generator structured to control the modulated signal source in first and second read cycles in which the second read cycle is consecutive to said first read cycle, each read cycle including a reset phase and a sense phase, the modulated electrical read signal presenting a first value in the reset phase of the first read cycle, a second value in the sense phase of the first read cycle, the second value in the reset phase of the second read cycle, and the first value in the sense phase of the second read cycle.