A fast and energy-efficient two-stage level shifter using the controlled Wilson current mirror

Multiple voltage domains are commonplace in modern SoCs and level shifter (LS) circuits allow different voltage domains to be interfaced with each other. As the reduced supply voltages are extensively used in digital blocks for low-power operation, the conversion of sub-threshold voltage levels to full VDD signal becomes a particular problem. In this paper we present a new LS structure for the fast and energy-efficient conversion of extremely low voltage levels. The proposed LS is a two-stage structure consisting of a controlled Wilson current mirror and eliminates the negative feedback mechanism. Inverted output of the second stage controls the current through the first stage. If the input signal is logical high (VDDL) then the circuit will produce high output (VDDH) and the first stage is prepared to conduct the current for logical 0 input (0V). This improves the slew rate problem and enables fast and energy-efficient operation. Considering process corners at a 90-nm technology node, the proposed design reliably converts 150-mV input signal into 1 V output signal. Post-layout results show that the proposed LS exhibits a propagation delay of 16 ns, a total energy per transition of only 79 fJ, and a static power dissipation of 16.6 nW for a 200 mV input signal at 1-MHz, while loading 100 fF of capacitive load

Genetic differentiation and geographical Relationship of Asian barley landraces using SSRs

Genetic diversity in 403 morphologically distinct landraces of barley (Hordeum vulgare L. subsp. vulgare) originating from seven geographical zones of Asia was studied using simple sequence repeat (SSR) markers from regions of medium to high recombination in the barley genome. The seven polymorphic SSR markers representing each of the chromosomes chosen for the study revealed a high level of allelic diversity among the landraces. Genetic richness was highest in those from India, followed by Pakistan while it was lowest for Uzbekistan and Turkmenistan. Out of the 50 alleles detected, 15 were unique to a geographic region. Genetic diversity was highest for landraces from Pakistan (0.70 ± 0.06) and lowest for those from Uzbekistan (0.18 ± 0.17). Likewise, polymorphic information content (PIC) was highest for Pakistan (0.67 ± 0.06) and lowest for Uzbekistan (0.15 ± 0.17). Diversity among groups was 40% compared to 60% within groups. Principal component analysis clustered the barley landraces into three groups to predict their domestication patterns. In total 51.58% of the variation was explained by the first two principal components of the barley germplasm. Pakistan landraces were clustered separately from those of India, Iran, Nepal and Iraq, whereas those from Turkmenistan and Uzbekistan were clustered together into a separate group