Analog digital conversion system and method for noise reduction in touch sensor by integrating analoise reduction in touch sensor by integrating analog input signal

PURPOSE: An analog to digital conversion system and a method for reducing noise in a touch sensor by integrating an analog signal are provided to measure time reaching a reference value by integrating a sample and a held signal. CONSTITUTION: A CDS(Correlated Double Sampling) circuit(110) extracts a signal factor generated by deducting a premeasured reference value from an analog wave signal received from an input terminal connected to a touch panel(200). A sampling circuit(120) changes an analog signal factor inputted from the CDS circuit into a signal of a step waveform. An integrator(130) integrates the signal of the step waveform for a predetermined time period. An output circuit(140) outputs a binary code according to sensing time by comparing a preset first reference value with an integrated value. The output circuit reduces noise from a touch sensor by integrating the analog signal.