| 1. |
- Alvbrant, Joakim, et al.
(författare)
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Transfer Characteristics and Bandwidth Limitation in a Linear-Drift Memristor Model
- 2015
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Ingår i: 2015 EUROPEAN CONFERENCE ON CIRCUIT THEORY AND DESIGN (ECCTD). - : IEEE. - 9781479998777 ; , s. 332-335
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Konferensbidrag (refereegranskat)abstract
- The linear-drift memristor model, suggested by HP Labs a few years ago, is used in this work together with two window functions. From the equations describing the memristor model, the transfer characteristics of a memristor is formulated and analyzed. A first-order estimation of the cut-off frequency is shown, that illustrates the bandwidth limitation of the memristor and how it varies with some of its physical parameters. The design space is elaborated upon and it is shown that the state speed, the variation of the doped and undoped regions of the memristor, is inversely proportional to the physical length, and depth of the device. The transfer characteristics is simulated for Joglekar-Wolf, and Biolek window functions and the results are analyzed. The Joglekar-Wolf window function causes a distinct behavior in the tranfer characteristics at cut-off frequency. The Biolek window function on the other hand gives a smooth state transfer function, at the cost of loosing the one-to-one mapping between charge and state. We also elaborate on the design constraints derived from the transfer characteristics.
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| 2. |
- Andersson Ersman, Peter, et al.
(författare)
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All-printed large-scale integrated circuits based on organic electrochemical transistors
- 2019
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The communication outposts of the emerging Internet of Things are embodied by ordinary items, which desirably include all-printed flexible sensors, actuators, displays and akin organic electronic interface devices in combination with silicon-based digital signal processing and communication technologies. However, hybrid integration of smart electronic labels is partly hampered due to a lack of technology that (de)multiplex signals between silicon chips and printed electronic devices. Here, we report all-printed 4-to-7 decoders and seven-bit shift registers, including over 100 organic electrochemical transistors each, thus minimizing the number of terminals required to drive monolithically integrated all-printed electrochromic displays. These relatively advanced circuits are enabled by a reduction of the transistor footprint, an effort which includes several further developments of materials and screen printing processes. Our findings demonstrate that digital circuits based on organic electrochemical transistors (OECTs) provide a unique bridge between all-printed organic electronics (OEs) and low-cost silicon chip technology for Internet of Things applications. © 2019, The Author(s).
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| 3. |
- Keshmiri, Vahid, et al.
(författare)
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A Current Supply with Single Organic Thin-Film Transistor for Charging Supercapacitors
- 2016
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Ingår i: THIN FILM TRANSISTORS 13 (TFT 13). - : ELECTROCHEMICAL SOC INC. - 9781607687276 ; , s. 217-222
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Konferensbidrag (refereegranskat)abstract
- We present a current supply, comprising a single organic thin-film transistor (OTFT), for the charging of supercapacitors. The current supply takes power from the electric grid (115 V AC, US standard), converts the AC voltage to a quasi-constant DC current (similar to 0.1 mA) regardless of the impedance of the load, and charges the supercapacitor. Solution-processed OTFTs based on the popular polymeric semiconductor poly(3-hexylthiophene- 2,5-diyl) have been developed to rectify the 115 V AC voltage. A diodeconfigured OTFT was used as a half-wave rectifier. The single OTFT current supply was demonstrated to charge a 220 mF supercapacitor to 1 V directly using 115 V AC voltage as the input. This work paves the road towards all-printable supercapacitor energy-storage systems with integrated chargers, which enable direct charging from a power outlet.
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| 4. |
- Keshmiri, Vahid, et al.
(författare)
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A Silicon-Organic Hybrid Voltage Equalizer for Supercapacitor Balancing
- 2017
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Ingår i: IEEE Journal on Emerging and Selected Topics in Circuits and Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2156-3357 .- 2156-3365. ; 7:1, s. 114-122
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Tidskriftsartikel (refereegranskat)abstract
- Cell voltage equalizers are an important part in electric energy storage systems comprising series-connected cells, for example, supercapacitors. Hybrid electronics with silicon chips and printed devices enables electronic systems with moderate performance and low cost. This paper presents a silicon-organic hybrid voltage equalizer to balance and protect series-connected supercapacitor cells during charging. Printed organic electrochemical transistors with conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are utilized to bypass excess current when the supercapacitor cells are fully charged to desired voltages. In this study, low-cost silicon microcontrollers (ATtiny85) are programmed to sense voltages across the supercapacitor cells and control the organic electrochemical transistors to bypass charging current when the voltages exceed 1 V. Experimental results show that the hybrid equalizer with the organic electrochemical transistors works in dual-mode, switched-transistor mode or constant-resistor mode, depending on the charging current applied (0.3-100 mA). With the voltage equalizer, capacitors are charged equally regardless of their capacitances. This work demonstrates a low-cost hybrid solution for supercapacitor balancing modules at large-scale packs.
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| 5. |
- Keshmiri, Vahid, et al.
(författare)
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The applications of OECTs in supercapacitor balancing circuits
- 2016
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Ingår i: 2016 7th International Conference on Computer Aided Design for Thin-Film Transistor Technologies (CAD-TFT). - : IEEE. - 9781509026876 ; , s. 23-23
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Konferensbidrag (refereegranskat)abstract
- In this paper, we investigate using OECTs in differential amplifiers and cell voltage equalizers for supercapacitor balancing circuits. The differential amplifier based on OECTs can sense voltage difference and the voltage equalizer consisting of a microcontroller and OECTs can be used to charge supercapacitors to desired voltages.
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