Patent ID: 8305248

Claim:
A time-to-digital converter comprising: a phase-difference enhancement section configured to receive first and second input signals having a reference phase difference Δt, and to output first and second output signals having an enhanced phase difference; and a comparison section configured to receive the first and second output signals, to compare a phase difference between the first and second output signals with a reference delay time τ, and to output a comparison signal, wherein the phase-difference enhancement section comprises first to N th phase-difference enhancers (wherein, “N” represents a natural number equal to or greater than 2), which are coupled in series with each other, wherein the first phase-difference enhancer receives the first and second input signals and generates first and second output signals having an enhanced phase difference, and the N th phase-difference enhancer receives first and second output signals of (N−1) th phase-difference enhancer and generates first and second output signals having an enhanced phase difference, wherein the comparison section comprises first to N th comparators, each being configured to receive first and second output signals from a corresponding phase-difference enhancer, to compare a phase difference between the first and second output signals with the reference delay time τ, and to output a comparison signal.