Analysis and Design of Energy Efficient Time Domain Signal Processing

Time domain signal processing (TDSP) encodes information into time rather than voltage with higher efficiency than conventional digital design. This paper performs systematical analysis on the design principle and energy efficiency of TDSP. Variation impact, which poses significant challenges to TDSP, is evaluated and a variation driven design methodology is proposed to achieve an optimum tradeoff between energy efficiency and design robustness. Several novel circuit level design techniques such as dual encoding strategy and bit-scalable design are also proposed in this work to significantly improve the energy efficiency of TDSP. Design example on a critical building block of facial recognition application was used to demonstrate the potential of the technique. The result in a 45nm technology shows 3.3X energy-delay product reduction and 34% area saving can be achieved using TDSP compared with conventional digital design technique.