In this paper, a study of bulk degeneration in a differential pair to enhance its linear range is initially conducted. A nanopower operational transconductance amplifier (OTA) is then proposed combining both source and bulk degeneration to achieve an increased linear range above 1 V with a power supply ranging from 1.9 V to 5.5 V. The circuit was fabricated in a 0.6 μm technology and measured. This linearity improvement is achieved with a negligible increase in power consumption, noise, and input referred offset. Finally a circuit implementing the full signal conditioning of a piezoelectric accelerometer for adaptive pacemakers is presented, as an application example of the proposed OTA. The circuit consumes only 500 nA, and it can discriminate signals of 15 μV, because of the low input referred offset <; 5 mV of the source-bulk linearized OTA.

In this letter, three battery-powered, custom Internet of Things (IoT) sensor nodes for the agribusiness, are presented: first, a Sigfox-based temperature-humidity index (THI) sensor to monitor the impact of heat stress in livestock, then a LoRaWAN version of an estrus detection collar for dairy farms, and finally a NB-IoT low-power A-GPS geolocation device for animals. Detailed power consumption measurements are presented and compared to highlight the benefits of each low-power wide-area network technology for the industry. The measured energy to transmit a single 10Byte payload packet was 90, 20, and 90 mJ for Sigfox, LoRa, and NB-IoT, respectively. With an adequate power management strategy, the nodes could operate up to 10 years in the case of the THI and estrus detector, and >1 yr in the case of the GPS tracker, powered by a single 1900 mA $\cdot \mathrm {h}~\mathrm {LiSOCl}_{2}$ battery.

Electronic shelf labels (ESL, or electronic price tag) are used by retailers for displaying product pricing on shelves substituting printed price tags; each ESL can display not only the price, but also text, and images, and can be remotely updated, configured, and programmed from a central server. Additionally, the emerging IoT paradigm, allows to expand the application horizon. Firstly, this work presents an analysis on how the use of Cloud-connected, intelligent, ESLs can improve food logistics in the complex scenarios of medium and large cities. Then, a low-cost ESL device, using an electronic ink (e-ink) display and the LoRaWAN protocol to communicate with the central server, aimed at price display and innovative applications in food retail and logistics, is presented. Several current consumption and communication distance measurements are shown, and the design and configuration space are explored to optimize battery life and communication reliability in the different food distribution scenarios. The proposed ESL is powered with a 500mA ·h LiMnO ₂ battery that can last for >8 years in a typical application, considering it communicates with a central server once per hour. The developed price tag can dynamically update the price and information for the customer, which in the case of food can be used to minimize spoilage and can easily upgraded to incorporate sensors or smartphone interaction to develop innovative food logistics and marketing practices. Finally, a LoRaWAN time-slot allocation strategy is presented, to minimize collisions when thousand nodes are connected to a single gateway, with a minimum power consumption overhead.

The design of Siwa ¹ , a compact low power custom system on chip (SoC), targeted for implantable/wearable applications, is reported in this paper. Siwa is based on a RISC-V RV32I architecture. It has a centrally controlled non-pipelined structure, and it includes a control interface for an integrated sensing and stimulation device for biological tissues as well as standard communication interfaces. Siwa was developed from scratch using System Verilog, and implemented in a 180nm CMOS technology; Siwa includes a latch based register file c apable to read and write in one clock cycle with an area 30% smaller and a power consumption 25% lower with respect to an equivalent flip flop implementation; also, it has an estimated average power consumption of 70μW (48pJ/cycle) which is comparable to other micro-controllers commonly used in IMD applications.

Open-source tools and PDKs facilitate the design, implementation and silicon validation of integrated circuits, circumventing the traditional barriers associated with this field. Power integrated circuits, conversely, are increasingly relevant in modern systems targeting energy-efficient applications. In this study, the design of a power integrated circuit is examined from the perspective of open-source silicon design, which has recently emerged as a feasible approach for acquiring functional silicon-proven designs with low entry barriers. Utilizing this workflow, we showcase the complete design, simulation, layout, and experimental validation of an integrated multilevel dc-dc converter: specifically, a three-level flying capacitor buck converter. Our system converts 3.3V dc bus levels to 1.8V and below, for a measured peak efficiency of 89.3%. The maximum measured load current is 250mA, using two conversion cores operating in interleaved mode. The system has been implemented in 6.27mm ² of active area using the Skywater 130nm standard CMOS technology open-source PDK.