Short time interval measurement using a time amplifer

A new architecture for on-chip measurement of short time intervals is proposed. In the proposed method, narrow time intervals are first amplified by a time amplifier (TAMP) and then measured by a time to digital converter. A delay locked loop (DLL) circuit is utilized to design a feedback time amplifier in which the gain is programmed by input data to any integer value within a range specified by the number of delay cells in the DLL. The TAMPpsilas gain remains rather unchanged under process and temperature variations due to the inherent negative feedback of the DLL system. The circuit is implemented using CMOS 0.18 mum technology occupying less than 0.63 mm² of silicon area. Simulation results show that the proposed scheme can successfully be employed to measure time intervals in the range of a few tens of picoseconds with an acceptable accuracy.