A 93% efficiency reconfigurable switched-capacitor DC-DC converter using on-chip ferroelectric capacitors

Dynamic Voltage Scaling (DVS) has become one of the standard techniques for energy efficient operation of systems by powering circuit blocks at the minimum voltage that meets the desired performance [1]. Switched Capacitor (SC) DC-DC converters have gained significant interest as a promising candidate for an integrated energy conversion solution that eliminates the need for inductors [2,3]. However, SC converters efficiency is limited by the conduction loss, bottom plate parasitic capacitance, gate drive loss in addition to the overhead of the control circuit. Reconfigurable SC converters supporting multi-gain settings have been proposed to allow efficient operation across wide output range [2,4]. Also, High density deep trench capacitors with low bottom plate parasitic capacitance have been utilized in [5] achieving a peak efficiency of 90%. In this work, we exploit on-chip ferroelectric capacitors (Fe-Caps) for charge transfer owing to their high density and extremely low bottom plate parasitic capacitance [6]. High efficiency conversion is achieved by combining the Fe-Caps with multi-gain setting converter in a reconfigurable architecture with dynamic gain selection

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