Patent ID: 7999716

Claim:
An analog-digital converter circuit comprising: a periodic signal output circuit receiving a temporally-varying analog signal as an input, replacing the analog signal with N serial periodic signals of a frequency corresponding to a magnitude of the analog signal, and outputting the N serial periodic signals; N pulse counting devices counting a number of pulses of the N serial periodic signals; and a digital signal generating circuit receiving the N serial periodic signals as an input and generating a digital signal corresponding to the magnitude of the analog signal from the periodic signals every sampling period, wherein the periodic signal generating circuit includes N converters converting a magnitude of an electric signal into a frequency and the converters generate the N serial periodic signals, and allows a first to j-th pulse counting devices of the N pulse counting devices to count a count value X and allows the other pulse counting devices to count a count value X−1 in each sampling period by sequentially delaying and generating the N serial periodic signals, and wherein the digital signal generating circuit converts the analog signal to the digital signal with a resolution N times higher than that for converting the analog signal into the digital signal in the sampling period on the basis of counting statuses of the N pulse counting devices.