Adaptive performance compensation with on-chip variation monitoring

This paper discusses adaptive performance control with two types of on-chip variation sensors. The first sensor aims to extract several device-parameters for performance adaptation from a set of on-chip ring-oscillators with different sensitivities to device-parameters, and the device-parameter decomposition is discussed. The second sensors, which are embedded into functional circuits, predict timing errors due to PVT variations and aging. By controlling circuit performance according to the sensor outputs, PVT worst-case design can be overcome and power dissipation can be reduced while satisfying performance requirements. Measurement results of a subthreshold adder on 65-nm test chips show that the adaptive speed control can compensate PVT variations and improve energy efficiency by up to 46% compared to the worst-case design and operation with guardbanding.