| 摘要 |
An apparatus and method for measuring a change in capacitance are provided. The apparatus includes a first gain adjuster, a second gain adjuster, an amplifier, a demodulator, a controller, and a change measuring unit. The first gain adjuster adjusts the gain of an input signal and outputs the gain-adjusted input signal to the first terminal as a first modulating signal, while the second gain adjuster adjusts the gain of an inverted input signal and outputs the gain-adjusted inverted input signal to the second terminal as a second modulating signal. The amplifier amplifies a modulated signal output from a junction between the first and second capacitors and outputs the amplified result. The demodulator that demodulates the amplified result received from the amplifier in response to a control signal and outputs the demodulated result. The controller generates the control signal per unit period of the input signal and outputs the generated control signal to the demodulator. The change measuring unit measures the change in capacitance from the demodulated result received from the demodulator. Accordingly, the apparatus and method compensate for an offset produced by parasitic capacitance without affecting the change in capacitance to be measured, thereby allowing for a precise measurement of the change in capacitance.
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