Logo image
Clock Buffer Polarity Assignment with Skew Tuning
Journal article   Peer reviewed

Clock Buffer Polarity Assignment with Skew Tuning

Jianchao Lu and Baris Taskin
ACM transactions on design automation of electronic systems, v 16(4)
01 Jan 2011

Abstract

Computer Science Computer Science, Hardware & Architecture Computer Science, Software Engineering Science & Technology Technology
A clock polarity assignment method is proposed that reduces the peak current on the vdd/gnd rails of an integrated circuit. The impacts of (i) the output capacitive load on the peak current drawn by the sink-level clock buffers, and (ii) the buffer/inverter replacement scheme of polarity assignment on timing accuracy are considered in the formulation. The proposed sink-level-only polarity assignment is performed by a lexi-search algorithm in order to balance the peak current on the clock tree. Most of the previous polarity assignment methods that do not include clock tree resynthesis lead to an undesirable increase in the worst corner clock skew. Hence, a skew-tuning scheme is proposed that reduces the clock skew through polarity refinement and not through clock tree resynthesis. The proposed polarity assignment method with the skew-tuning scheme is implemented within an industrial design flow for practicality. Experimental results show that the worst-case peak current drawn by the clock tree can be reduced by an average of 36.5%. The worst corner clock skew is increased from 60.7ps to 76.2ps by applying the proposed polarity assignment method. The proposed skew-tuning scheme reduces the worst-case clock skew from 76.2ps to 61.5ps, on average, with a limited degradation in the peak current improvement (36.5% to 31.2%, on average).

Metrics

4 Record Views
4 citations in Scopus

Details

InCites Highlights

Data related to this publication, from InCites Benchmarking & Analytics tool:

Web of Science research areas
Computer Science, Hardware & Architecture
Computer Science, Software Engineering
Logo image