Patent ID: 7920004

Claim:
An apparatus for duty cycle correction which corrects the duty cycle of a square-wave signal having a distorted duty cycle, wherein the square-wave signal is a signal having samples with a period that is shorter than that of the square-wave signal, the apparatus comprising: a moving sum unit performing a moving sum calculation with respect to the square-wave signal and outputting a moving sum signal based on the moving sum calculation; a comparison unit comparing the moving sum signal with a predetermined threshold voltage, outputting a high signal when the moving sum signal is higher than the predetermined threshold voltage, and outputting a low signal when the moving sum signal is lower than the predetermined threshold voltage; a mean value calculation unit calculating a mean value of an output signal outputted from the comparison unit, the output signal being included in a section having a period that is n times greater than that of the square-wave signal, wherein n is an integer; and a threshold voltage control unit comparing the mean value calculated by the mean value calculation unit with a middle value between the high and low signals, increasing the predetermined threshold voltage when the mean value is greater than the middle value, and decreasing the predetermined threshold voltage when the mean value is less than the middle value.