Wide duty cycle range synchronous mirror delay designs

A wide duty cycle range and small static phase error synchronous mirror delay (SMD) for system-on-chip (SoC) applications is presented. The conventional SMD accepts only the pulsed clock signal and has large static phase error. The proposed SMD uses the edge-trigger mirror delay cell to enlarge the input duty cycle range and the blocking edge-trigger scheme to ensure functionality and performance. Moreover, phase error can be reduced by the proposed delay-matching structure and fine-tuning delay line with a high-resolution delay cell. Simulation results of SMD show that the input clock duty cycle range is from 20 to 80% and the worst static phase error under different process, voltage, and temperature conditions can achieve 18 ps at 400 MHz.