Charge recycling in MTCMOS circuits: concept and analysis

Designing an energy efficient power gating structure is an important and challenging task in multi-threshold CMOS (MTCMOS) circuit design. In order to achieve a very low power design, the large amount of energy consumed during mode transition in MTCMOS circuits should be avoided. In this paper, we propose an appropriate charge recycling technique to reduce energy consumption during the mode transition of MTCMOS circuits. The proposed method can save up to 46% of the mode transition energy while, in most cases, maintaining, or even improving, the wake up time of the original circuit. It also reduces the peak negative voltage value and the settling time of the ground bounce.