| 摘要 |
PURPOSE: A capacitive sensor interface is provided to effectively reduce noise which is increased during the sensing process of signal by the acceleration senor or the treatment process of sensed signal. CONSTITUTION: A capacitive sensor interface(100) comprises a signal generator(110) and a sensor interface circuit(120). A signal generator generates the input signal of X-axis, Y-axis, and Z-axis inputted to a variable capacitor for sensing acceleration. A sensor interface circuit comprises a multiplexor(121), an operational trans-conductance amplifier(122), and a programmable gain amplifier(123). A multiplexor outputs one of the sensing currents as an input current after the input signal converts into the sensing currents of X-axis, Y-axis, and Z-axis by a variable capacitor. An operational trans-conductance amplifier outputs an input current as the first output value by receiving an input current and the first standard voltage. A programmable fain amplifier outputs the first output value after converting it into the second output value by receiving the first output value and the second standard voltage. |
