TIME-TO-DIGITAL CONVERTER (TDC) WITH IMPROVED RESOLUTION

摘要

PROBLEM TO BE SOLVED: To provide a time-to-digital converter (TDC) with high resolution of inverter delay less than one inverter delay.SOLUTION: A TDC 500 includes first and second delay paths 510a, 510b, a delay unit 520, and a phase computation unit 530. 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 by one-half of 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 is performed to obtain accurate timing for the first and second delay paths.SELECTED DRAWING: Figure 5