A critical-path monitor for DVFS systems without datapath replication

The benefits of technology scaling have been accompanied by undesirable variations of a large number of parameters that need to be offset to ensure the proper operation of current electronic systems. Timing uncertainties are one of the most dangerous of these variation because they jeopardize the performance of the whole system. Critical-path monitors in conjunction with DVFS control systems have appear as a promising solution to these problems. Traditional approaches employ synthesized replicas of the critical-path to perform the measurement. This work proposes a novel method to measure the delay of a critical-path through a monitor that does not employ datapath replication, but rather takes the measurement from the actual critical path. The monitor has been validated in a 90 nm technology, it takes an area of 9623 μm², consumes an energy per measurement of 38 pJ and achieves an accuracy of 30 ps for the worst technology corner.