A 10-bit SAR ADC with an Ultra-Low Power Supply

This paper presents a successive approximation analog-to-digital converter (SAR ADC) design, which operates with a 0.2 V power supply. The design utilizes a dynamic bulk biasing scheme to dynamically adjust the relative NMOS and PMOS strengths, which are very sensitive to temperature, process, and mismatch variations at low supply voltages. The design achieves a very low power consumption due to the 0.2 V supply. Several circuits in the design are optimized for full functionality at 0.2 V. Extracted simulations show a total power consumption of 9 nW with a peak SNDR of 61.3 dB and a Walden Figure of Merit of 1.91 fJ/conversion-step

Prolonged energy harvesting for ingestible devices

Ingestible electronics have revolutionized the standard of care for a variety of health conditions. Extending the capacity and safety of these devices, and reducing the costs of powering them, could enable broad deployment of prolonged-monitoring systems for patients. Although previous biocompatible power-harvesting systems for in vivo use have demonstrated short (minute-long) bursts of power from the stomach, little is known about the potential for powering electronics in the longer term and throughout the gastrointestinal tract. Here, we report the design and operation of an energy-harvesting galvanic cell for continuous in vivo temperature sensing and wireless communication. The device delivered an average power of 0.23 μW mm⁻² of electrode area for an average of 6.1 days of temperature measurements in the gastrointestinal tract of pigs. This power-harvesting cell could provide power to the next generation of ingestible electronic devices for prolonged periods of time inside the gastrointestinal tract.National Institutes of Health (U.S.) (Grant EB-000244

Prolonged energy harvesting for ingestible devices

Ingestible electronics have revolutionized the standard of care for a variety of health conditions. Extending the capacity and safety of these devices, and reducing the costs of powering them, could enable broad deployment of prolonged monitoring systems for patients. Although prior biocompatible power harvesting systems for in vivo use have demonstrated short minute-long bursts of power from the stomach, not much is known about the capacity to power electronics in the longer term and throughout the gastrointestinal tract. Here, we report the design and operation of an energy-harvesting galvanic cell for continuous in vivo temperature sensing and wireless communication. The device delivered an average power of 0.23 μW per mm2 of electrode area for an average of 6.1 days of temperature measurements in the gastrointestinal tract of pigs. This power-harvesting cell has the capacity to provide power for prolonged periods of time to the next generation of ingestible electronic devices located in the gastrointestinal tract

Data driven optimization in SAR ADC

Recent publications show that successive approximation register (SAR) analog to digital converters (ADC) are capable of achieving high efficiency over other ADC topologies. Furthermore, techniques have been adopted to process signals with low activity periods, such as biomedical and industrial sensors. Prior work used least- significant bit first quantization (LSBFQ) to conserve capacitor switching energy and comparator decisions (bitcycles). This work improves on the published least significant bit (LSB) first successive approximation ADC by restructuring its algorithm for further energy efficient switching, lowering its bitcycle range, and extending its range of applications. For target applications, these proposed solutions will outperform the bit-skipping LS­BFQ and the merged capacitor switching (MCS) SAR, the most energy-efficient traditional most significant bit (MSB) first SAR.Keywords: Adaptive SAR, ADC, LSB-First, LSB First, LSBFQ, SAR, ASB, SSB, Successive Approximation Algorith