An Energy-Recovering Reconfigurable Series Resonant Clocking Scheme for Wide Frequency Operation

On-chip low skew clock distribution driving large load capacitances can consume as much as 70% of the total dynamic power that is lost as heat, resulting in high cooling costs. To mitigate this, an energy recovering reconfigurable series resonance solution with all the critical support circuitry is described. This LC resonant clock driver on a 22 nm process node saves about 50% driver power (>40% overall) and has 50% less skew than non-resonant driver at 2 GHz, while operating down to 0.2 GHz for dynamic voltage and frequency scaling. Reconfiguring for pulse mode operation enables further power saving, using latches instead of flip-flop banks, for double data rate applications. Tradeoffs in timing performance versus power, based on theoretical analysis, are compared and verified, to enable synthesis of an optimal topology for a given application.