A fully static topologically-compressed 21-transistor flip-flop with 75% power saving

An extremely low-power flip-flop named topologically-compressed flip-flop (TCFF) is proposed. As compared with conventional flip-flops, the novel FF reduces power dissipation by 75% at 0% data activity. This power reduction ratio is the highest among FFs that have been reported so far. The reduction is achieved by applying topological compression method, merger of logically equivalent transistors to an unconventional latch structure. The very small number of transistors, only three, connected to clock signal reduces the power drastically, and the smaller total transistor count assures the same cell size as conventional FFs. In addition, fully static full-swing operation makes the cell tolerant of supply voltage and input slew variation. An experimental chip design with 40-nm CMOS shows that almost all conventional FFs are replaceable with proposed FF while preserving the same system performance and layout size.