Abstract:
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.
Abstract:
An analog to digital converter and an analog to digital converting method are provided to reduce power consumption and a chip size in comparison with the analog to digital converter comprised of a plurality of comparators comprised of pre-amplifiers. A reference voltage generator(10) generates a plurality of different reference voltages. A delay unit(20) changes a size of an analog input signal and the size and difference of a plurality of reference voltages into the delay time difference of an inputted clock. A phase detector(30) detects the delay time difference of the clock and generates the detection signal. A code generator(100) receives the detection signal and converts the detection signal into an N bit digital signal which increases as the analog input signal increases. The delay unit includes a first delay cell and a second delay cell. The first delay cell receives the clock and delays the clock as much as the first delay time according to the analog input signal. The second delay cell receives the clock and delays the clock as much as the second delay time according to the one reference voltage among the plurality of reference voltages.