Refinements to the regenerative carry scheme

The regenerative carry propagation/generation scheme has been found to be fast, area efficient, and power efficient. A novel generate-driven precharge circuit is presented which permits more speed and reduces precharge power consumption. Novel operating conditions are shown to permit several bits of carry propagation during the precharge phase itself, thereby shortening the following propagation phase. Carry look-ahead is also facilitated by the refinements presented. Comparison with the variable-block adder technique shows that regenerative carry enjoys a lower speed-power product. Simulation results are presented