A universal delay monitor used to imitate the real critical paths is developed for variation resilient integrated circuit. This monitor is constructed based on the different proportion of logic cells and interconnects. The delay of the monitor is detected by a time-to-digital converter which keeps the sampling results precise. To reduce the deviation of the sampling results caused by PVT, a novel time-to-digital converter with self-calibration mechanism is developed. This variation resilient method based adaptive voltage scaling is applied on an ARM7 based System on a Chip on 0.18 μm CMOS process with a 112M signoff frequency and an area of 1.3∗1.3 mm2. The simulation results show that it has a 43.42% gain of power consumption under FF corner, -25°C compared to the fixed 1.8 V traditional design.