Time-to-digital converter (TDC) with improved resolution

摘要

A time-to-digital converter (TDC) with fine resolution of less than one inverter delay is described. In an exemplary design, the TDC includes first and second delay paths, a delay unit, and a phase computation unit. The first delay path receives a first input signal and a first reference signal and provides a first output. The second delay path receives a second input signal and a second reference signal and provides a second output. The delay unit delays the second input signal relative to the first input signal or delays the second reference signal relative to the first reference signal, e.g., by one half inverter delay. The phase computation unit receives the first and second outputs and provides a phase difference between the input signal and the reference signal. Calibration may be performed to obtain accurate timing for the first and second delay paths.

主权项

1. An apparatus comprising:
a first delay path configured to receive a first input signal and a first reference signal and to provide a first output indicative of a phase difference between the first input signal and the first reference signal; a second delay path configured to receive a second input signal and a second reference signal and to provide a second output indicative of a phase difference between the second input signal and the second reference signal; and a delay unit configured to delay one from the group consisting of the second input signal and the second reference signal by a one half inverter delay relative to one of the first input signal and first reference signal, respectively.