58 research outputs found

    A flexible ECG patch compatible with NFC RF communication

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    With the advent of the internet of things, flexible wearable devices are gaining significant research interest, as they are unobtrusive, comfortable to wear and can support continuous observation of physiological signals, helping to monitor wellness or diagnose diseases. Amorphous Indium Gallium Zinc Oxide (a-IGZO) Thin Film Transistors (TFTs) fabricated on flexible substrates are an attractive option to build such bio-signal monitoring systems due to their flexibility, conformability to the human body, and low cost. This paper presents a flexible electrocardiogram (ECG) patch implemented on foil with self-aligned IGZO TFTs, which is capable to acquire the ECG signals, amplify them and convert them to a sequence of bits. The analogue frontend has a measured input-referred noise of 8 μVrms in the 1–100 Hz band. The system achieves experimentally 67.4 dB CMRR, 58.9 dB PSRR, and 16.5 MΩ input impedance at 50 Hz while using 1 kHz chopping. The signal from the electrodes is transformed to a 105.9-kb/s Manchester-encoded serial bit stream which could be sent wirelessly to a smart phone via Near Field Communication (NFC) for further elaboration. Power consumption is 15.4 mW for the digital and 280 μW for the analogue part. This contribution shows the fundamental steps to demonstrate intelligent plasters for biomedical applications based on flexible electronics providing an NFC-compatible digital output bit stream

    Implicit Heterogeneous 1D/2D Coupling for Aero-Thermo-Mechanical Simulation of Secondary Air Systems

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    The paper presents a computational procedure for heterogeneous coupled analysis of 1D flow network models of air engine secondary air systems and 2D/3D solid thermo-mechanical finite element models of engine components. We solve an unsteady heat transfer problem over solid domain coupled to a sequence of structural static and steady flow problems using a quasi-steady state approximation. Strong coupling is achieved at each time step by a fixed-point iteration, based on the successive solution of the fluid and the solid sub-problems. The procedure is applied to a 2D axisymmetric finite element model of an intermediate pressure turbine assembly coupled to a flow network model of whole engine secondary air system simulated through a square cycle. The simulation results are compared to reference stand-alone predictions showing important non-negligible coupled effects and component interactions of a multidisciplinary multi-physical nature resolved in an efficient and automatic fashion

    An organic integrated capacitive DC-DC up-converter

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    \u3cp\u3eIn this paper a fully integrated organic DC-DC upconverter is presented in a pentacene p-type only technology. This 3-stage Dickson converter reaches a voltage conversion factor of 3 for a purely capacitive load and 2.5 for a 10 μA load current. The maximal output voltage goes up to 75 V and the Dickson core efficiency is 48 %. The clock signal is generated on-chip with a 9-stage ring oscillator, built with zero-V\u3csub\u3egs\u3c/sub\u3e load inverters. A tunable input voltage provides a tuning range of 30 %. The presented converter is designed for the on-chip generation of voltages for biasing a capacitive load. This converter draws 560 μA from a 20 V supply voltage. The chip area measures 2.8x2.1 mm\u3csup\u3e2\u3c/sup\u3e. This converter fulfills a direct need for bias voltages beyond the supply voltage that is uncovered in recent work on organic circuits.\u3c/p\u3

    A Flexible Thin-Film Pixel Array with a Charge- to-Current Gain of 59μA/pC and 0.33% Nonlinearity and a Cost Effective Readout Circuit for Large-Area X-ray Imaging

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    We report an active, medical-grade, high resolution, high dynamic range X-ray backplane based on a-IGZO thin-film technology with fast readout. This enables low dose, video rate X-ray imaging. Fast X-ray imaging will find its applications not only in medical, but also in non-destructive inspection. Curved imagers will yield sharper images when illuminated from a point source. This has been achieved thanks to superior a-IGZO technology and a pixel topology that improves noise performance and allows a cost-effective external readout.status: publishe

    Impact of source/drain contacts formation of self-aligned amorphous-IGZO TFTs on their negative-bias-illumination-stress stabilities

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    In this study, we have compared the performance of self-aligned a-IGZO thin-film transistors (TFTs) whereby the source/drain (S/D) region's conductivity enhanced in three different ways, that is, using SiNx interlayer plasma (hydrogen diffusion), using calcium (Ca as reducing metal) and using argon plasma (changing the atomic ratio). All these TFTs show comparable characteristics such as field-effect mobility (μFE) of over 10.0 cm2/(V.s), sub-threshold slope (SS-1) of 0.5 V/decade, and current ratio (ION/IOFF) over 108. However, under negative-bias-illumination-stress (NBIS), all these TFTs showed strong degradation. We attributed this NBIS stability issue to the exposed S/D regions and changes in the conductivity of S/D contact regions. The hydrogen plasma-treated TFTs showed the worst NBIS characteristics. This is linked to increased hydrogen diffusion from the S/D contact regions to the channelstatus: publishe
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