Low power latch based design with smart retiming

Abstract

Flip-flops and latches are two options to construct pipelines in digital integrated circuits (ICs). In this paper, the implications for converting a flip-flop based design to a latch-based design are investigated by performing timing and power analysis. Design flows are also proposed to convert a flip-flop based design to a latch-based design as well as a latch/flip-flop-mixed design. With a new retiming strategy, the optimum operating condition is identified for both the latch based design and the mixed design, where the maximum time borrowing or performance enhancement can be obtained. Compared to the flip-flop based design, 48% and 45% frequency boosting are achieved by the latch based design and the mixed design, respectively. While maintaining the same performance as the flip-flop based design with the aid of supply voltage scaling, the latch based design and the mixed design reduce the power consumption by 21% and 16%, respectively, in an industrial 28-nm FDSOI CMOS technology.