Metastability immune and area efficient error masking flip-flop for timing error resilient designs

Abstract

Reducing the worst case timing guard bands is one of the major concerns in high performance designs with limited power budget in the advanced nano-scale technology nodes. In this work, an error masking flip-flop is proposed to reduce the worst case timing guard bands by detecting and correcting timing violations. It consists of a pulse generator, an error detector and a multiplexer along with a conventional flip-flop. Exploiting an intermediate multiplexer between master and slave latch of a conventional flip-flop, the erroneous output state of the flip-flop due to timing violations is corrected by providing direct data to slave latch. The proposed flip-flop occupies 16% less area compared to error masking flip-flops available in literature. A core level clock gating is employed for error recovery which shifts the rising edge of the clock by one period in case of a timing violation. ISCAS’89 benchmark circuits, a 32-bit pipelined adder and a 16-bit pipelined multiplier are implemented in 130nm technology, which use error masking flip-flop for dynamic voltage and frequency scaling (DVFS). It is shown that using error masking flip-flops with DVFS can either reduce power consumption up to 20% or improve the performance up to 32% in typical operating conditions compared to worst case design.