In this paper, Two energy-efficient switching schemes based on close-loop charge recycling method are presented. In each transition, required capacitors with an initial charge will be connected to the capacitor arrays, while the bottom plates of all capacitors are connected to the same reference voltage. This method does not let capacitors to drain any DC current from the reference voltage, and existing charge on the capacitors will be shared on their top plates to provide the required threshold voltage. Two proposed schemes are simulated in MATLAB and the results show a 100 % transitional energy saving during bits generation for both proposed techniques, without considering reset phase. In addition, the first and the second schemes show 25% and 50% capacitor area reductions in comparison with the conventional scheme, respectively.
