A Biofuel-Cell-Based Energy Harvester With 86% Peak Efficiency and 0.25-V Minimum Input Voltage Using Source-Adaptive MPPT

This article presents an efficient cold-starting energy harvester system, fabricated in 65-nm CMOS. The proposed harvester uses no external electrical components and is compatible with biofuel-cell (BFC) voltage and power ranges. A power-efficient system architecture is proposed to keep the internal circuitry operating at 0.4 V while regulating the output voltage at 1 V using switched-capacitor dc–dc converters and a hysteretic controller. A startup enhancement block is presented to facilitate cold startup with any arbitrary input voltage. A real-time on-chip 2-D maximum power point tracking with source degradation tracing is also implemented to maintain power efficiency maximized over time. The system performs cold startup with a minimum input voltage of 0.39 V and continues its operation if the input voltage degrades to as low as 0.25 V. Peak power efficiency of 86% is achieved at 0.39 V of input voltage and 1.34 μW of output power with 220 nW of average power consumption of the chip. The end-to-end power efficiency is kept above 70% for a wide range of loading powers from 1 to 12 μW. The chip is integrated with a pair of lactate BFC electrodes with 2 mm of diameter on a prototype-printed circuit board (PCB). Integrated operation of the chip with the electrodes and a lactate solution is demonstrated

The incidence and prevalence of acromegaly, a nationwide study from 1955 through 2013.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageAcromegaly is a rare disease with complications and increased mortality. The incidence and prevalence of acromegaly worldwide is not well known.To gather information on patients diagnosed with acromegly in Iceland over 59 years.Information was retrospectively gathered about patients diagnosed with acromegaly from 1955 through 2013. Incidence was calculated from the total Icelandic population.Information was gathered from medical records at Landspitali National University Hospital, Iceland, housing the only endocrine department in the country, at the largest hospital outside of Reykjavik (Sjúkrahúsið á Akureyri, Akureyri Hospital) and the largest private outpatient clinic in Reykjavik, where some of the patients received follow-up care. Further, information on patients were sought from all endocrinologists treating adult patients in Iceland. All patients diagnosed with acromegaly during the study period were included.Fifty-two patients (32 men) were diagnosed during the study period. The average age at diagnosis was 44.5 years. Nine patients had died. Symptoms had been present for more than 3 years in most cases. Twenty-five patients had hypertension (48 %). Follow up information was available for 48 patients, 63 % were considered cured after treatment.The incidence of acromegaly in Iceland during the study period was much higher than earlier reports have indicated. During the last 9 years of the study 7.7 patients were diagnosed per million per year. At diagnosis, 38 % had developed hypertension and 10 % were diagnosed during follow up. This indicates the importance of endocrine disorders in the aetiology of hypertension

A Fully-Integrated Biofuel-Cell-Based Energy Harvester with 86% Peak Efficiency and 0.25V Minimum Input Voltage Using Source-Adaptive MPPT

This paper presents a cold-starting energy harvester in 65nm CMOS with source degradation tracking and automatic MPPT. A power-efficient architecture is proposed to keep the internal circuitry operating at 0.4V while regulating the output voltage at 1V using switched-capacitor DC-DC converters and a hysteresis controller. Peak efficiency of 86% is achieved at 0.39V input voltage and 1.34μW of output power with 220nW of internal average power consumption. Integrated operation with lactate biofuel cells is demonstrated

A Fully-Integrated Biofuel-Cell-Based Energy Harvester with 86% Peak Efficiency and 0.25V Minimum Input Voltage Using Source-Adaptive MPPT

This paper presents a cold-starting energy harvester in 65nm CMOS with source degradation tracking and automatic MPPT. A power-efficient architecture is proposed to keep the internal circuitry operating at 0.4V while regulating the output voltage at 1V using switched-capacitor DC-DC converters and a hysteresis controller. Peak efficiency of 86% is achieved at 0.39V input voltage and 1.34μW of output power with 220nW of internal average power consumption. Integrated operation with lactate biofuel cells is demonstrated