Patent ID: 9671252
Date: 2017-06-06
CPC Classifications: G01D

Claim:
1. An apparatus of detecting capacitance which detects a capacitance change of a capacitive sensor, the apparatus comprising: a pulse modulator configured to output a charging signal including at least one pulse; a switch configured to charge the capacitive sensor according to the charging signal and output a discharging signal from the capacitive sensor; a discharging compensator configured to output a discharging delay signal by compensating a voltage level of the discharging signal during a falling period of the discharging signal; a detector configured to output a detection signal by detecting a region where the discharging delay signal has a voltage threshold; and a controller configured to detect the capacitance change by measuring a discharging time of the capacitive sensor according to the detection signal, wherein the discharging compensator receives a compensation signal including a pulse which has a constant size from the controller, and increases the voltage level of the discharging signal by using the compensation signal, and wherein the discharging compensator comprises: a discharging delayer configured to output a compensation delay signal by delaying the compensation signal for a set period of time; and an adder configured to output the discharging delay signal by adding the discharging signal and the compensation delay signal.