Variation Resilient Adaptive Controller for Subthreshold Circuits

Subthreshold logic is showing good promise as a viable ultra-low-power circuit design technique for power-limited applications. For this design technique to gain widespread adoption, one of the most pressing concerns is how to improve the robustness of subthreshold logic to process and temperature variations. We propose a variation resilient adaptive controller for subthreshold circuits with the following novel features: new sensor based on time-to-digital converter for capturing the variations accurately as digital signatures, and an all-digital DC-DC converter incorporating the sensor capable of generating an operating operating Vdd from 0V to 1.2V with a resolution of 18.75mV, suitable for subthreshold circuit operation. The benefits of the proposed controller is reflected with energy improvement of up to 55% compared to when no controller is employed. The detailed implementation and validation of the proposed controller is discussed

Subthreshold FIR Filter Architecture for Ultra Low Power Applications

Subthreshold design has been proposed as an effective technique for designing signal processing circuits needed in wireless sensor nodes powered by sources with limited energy. In this paper we propose a subthreshold FIR architecture which brings the benefits of reducedleakage energy, reduced minimum energy point, reduced operating voltage and increased operating frequency when compared with recently reported subthreshold designs. We shall demonstrate this through the design of a 9-tap FIR filter operating at 220mV with operational frequency of 126kHz/sample consuming 168.3nW or 1.33pJoules/sample. Furthermore, the area overhead of the proposed method is less than that of the transverse structure often employed in subthreshold filter designs. For example, a 9-tap filter based on transverse structure has 5X higher area than the filter designed using our proposed method

Subthreshold FIR filter architecture for ultra low power applications

Subthreshold design has been proposed as an effective technique for designing signal processing circuits needed in wireless sensor nodes powered by sources with limited energy. In this paper we propose a subthreshold FIR architecture which brings the benefits of reduced leakage energy, reduced minimum energy point, reduced operating voltage and increased operating frequency when compared with recently reported subthreshold designs. We shall demonstrate this through the design of a 9-tap FIR filter operating at 220 mV with operational frequency of 126 kHz/sample consuming 168.3 nW or 1,33 pJoules/sample. Furthermore, the area overhead of the proposed method is less than that of the transverse structure often employed in subthreshold filter designs. For example, a 9-tap filter based on transverse structure has 5* higher area than the filter designed using our proposed method