A 82nW chaotic-map true random number generator based on sub-ranging SAR ADC

An ultra-low power true random number generator (TRNG) based on sub-ranging SAR ADC is proposed. The proposed TRNG shares the coarse-ADC circuit with sub-ranging SAR ADC for area reduction. The shared coarse-ADC not only plays the role of discrete-time chaotic circuit or TRNG's entropy source but also reduces overall SAR ADC energy consumption by selectively activating the fine-SAR ADC. Also, the proposed dynamic residue amplifier and adaptive-reset comparator generate chaotic map with low power consumption. TRNG core occupies 0.0045mm 2 in 0.18??m CMOS technology and consumes 82nW at 270kbps throughput with 0.6V supply. The proposed TRNG passes all NIST tests and it achieves a state-of-the-art FOM of 0.3pJ/bit

A 82-nW Chaotic Map True Random Number Generator Based on a Sub-Ranging SAR ADC

An ultra-low power true random number generator (TRNG) based on a sub-ranging SAR analog-to-digital converter (ADC) is proposed. The proposed TRNG is composed of a coarse-SAR ADC with a low-power adaptive-reset comparator and a low-power dynamic amplifier. The coarse-ADC part is shared with a sub-ranging SAR ADC for area reduction. The shared coarse-ADC not only plays the role of discrete-time chaotic circuit but also reduces the overall SAR ADC energy consumption by selectively activating the fine-SAR ADC. Also, the proposed dynamic residue amplifier consumes only 48 nW and the adaptive-reset comparator generates a chaotic map with only 6-nW consumption. The proposed TRNG core occupies 0.0045 mm(2) in 0.18-mu m CMOS technology and consumes 82 nW at 270-kbps throughput with 0.6-V supply. It successfully passes all of National Institute of Standards and Technology (NIST) tests, and it achieves the state-of-the-art figure-of-merit of 0.3 pJ/bit

Battery-free wireless imaging of underwater environments

AbstractImaging underwater environments is of great importance to marine sciences, sustainability, climatology, defense, robotics, geology, space exploration, and food security. Despite advances in underwater imaging, most of the ocean and marine organisms remain unobserved and undiscovered. Existing methods for underwater imaging are unsuitable for scalable, long-term, in situ observations because they require tethering for power and communication. Here we describe underwater backscatter imaging, a method for scalable, real-time wireless imaging of underwater environments using fully-submerged battery-free cameras. The cameras power up from harvested acoustic energy, capture color images using ultra-low-power active illumination and a monochrome image sensor, and communicate wirelessly at net-zero-power via acoustic backscatter. We demonstrate wireless battery-free imaging of animals, plants, pollutants, and localization tags in enclosed and open-water environments. The method’s self-sustaining nature makes it desirable for massive, continuous, and long-term ocean deployments with many applications including marine life discovery, submarine surveillance, and underwater climate change monitoring.</jats:p