A comprehensive compensation technique for process variations and environmental fluctuations in digital integrated circuits

Abstract

Abstract-Process variability and environmental fluctuations deeply affect the digital circuits performance in many different ways, one of them, the data processing time which may cause error on synchronous digital circuits due to underestimated time violations. This situation is commonly avoided adding time margins to the clock signal making it larger than nominal worstcase data process time, penalizing the global performance. In this paper a new mechanism for compensating both environmental fluctuations and process parameters variations effects on digital circuits is presented. The environmental compensation mechanism regenerates the clock signal for a pipelined system stages adding a compensated skew component depending on the local environmental conditions of every one of these stages. The process variations are corrected with a calibration circuit which adjusts the clock period in every stage taking into account its particular static deviations.

Analysis of delay mismatching of digital circuits caused by common environmental fluctuations

“…Process variability, due to its static natures may be partially alleviated by static solutions like layout techniques, introduce corrections steps in the process, etc., but dynamic environmental conditions cannot be treated in the same way because its completely different nature. Techniques to dynamically compensate the effects of process variation [9], [2], temperature [3], voltage and temperature [4], [10] and Process variability-Temperature&Voltage [5] deviations all of them to be used in post-silicon phase and should take into account the mismatch effect shown along this work. …”

“…For all these reasons, environmental conditions fluctuation should be considered as dynamic variability source with a growing tendency that must be taken into account, and special attention must be payed to its mutual relation with the process variability in order to prevent time violations in digital circuits. In recent literature, compensating techniques for temperature and voltage fluctuations have been proposed, all of them based on the introduction of circuits that track the effects of them on logic circuitry [2], [3], [4], [5].…”