A time-to-digital converter apparatus including a delay phase-locked loop, a subtracter, a multi-phase detector and a Vernier detector is disclosed. The delay phase-locked loop herein includes digital delay components for producing counting signals. The multi-phase detector includes digital delay components for producing delay outputs according to the counting signals and thereby detecting a pulse input signal. The Vernier detector includes digital delay components for detecting the remainder of the pulse input signal according to the difference between the delay outputs produced by the subtracter.