Low-Voltage Tunable Pseudo-Differential Transconductor with High Linearity

Juan Antonio Gómez,Melita Pennisi,Antonio Lopez Martin,Ramon González Carvajal,Jaime Ramírez-Angulo,Manuel Pedro Carrasco 한국전자통신연구원 2009 ETRI Journal Vol.31 No.5

A novel tunable transconductor is presented. Input transistors operate in the triode region to achieve programmable voltage-to-current conversion. These transistors are kept in the triode region by a novel negative feedback loop which features simplicity, low voltage requirements, and high output resistance. A linearity analysis is carried out which demonstrates how the proposed transconductance tuning scheme leads to high linearity in a wide transconductance range. Measurement results for a 0.5 μm CMOS implementation of the transconductor show a transconductance tuning range of more than a decade (15 μA/V to 165 μA/V) and a total harmonic distortion of -67 dB at 1 MHz for an input of 1 Vpp and a supply voltage of 1.8 V.

Ultra‑Low Voltage Metal Oxide Thin Film Transistor by Low‑Temperature Annealed Solution Processed LiAlO2 Gate Dielectric

Anand Sharma,Nitesh K. Chourasia,Vishwas Acharya,Nila Pal,Sajal Biring,Shun-Wei Liu,Bhola N. Pal 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.1

Low surface-roughness and high-capacitance ion-conducting LiAlO2 gate dielectric thin flm has been fabricated by sol–gel technique to develop ultra-low voltage (≤1.0 V) indium-zinc-oxide thin flm transistor (TFT). This LiAlO2 dielectric shows α-LiAlO2 and γ-LiAlO2 phases those have been fabricated at two diferent temperatures. For both phases, mobile Li-ion is responsible to achieve a high dielectric constant (κ) of the material that helps to reduce the operating voltage of TFT. Additionally, lower surface roughness of LiAlO2 thin flm creates a low-density trap state in the semiconductor/dielectric interface which is capable to reduce operating voltage within 1.0-volt. The device with 700 °C annealed γ-LiAlO2 gate dielectric shows the best device performance with an electron mobility of 25 cm2 V−1 s−1 and an on/of ratio of 3×105 . Instead, 350 °C annealed α-LiAlO2 dielectric require only one volt to saturate the drain current and shows its mobility and on/of ratio are 13.5 cm2  V−1 s−1 and 1×104 respectively. Such kind of unusually low operation voltage TFT fabrication becomes possible because of the higher Li+ mobility of α-LiAlO2 gate dielectric and very low surface trap density. A model on carrier transport mechanism has been prepossessed to explain this achievement.

Low-Voltage-Operated Highly Sensitive Graphene Hall Elements by Ionic Gating

Kim, Joonggyu,Na, Junhong,Joo, Min-Kyu,Suh, Dongseok American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.4

<P>The advanced Hall magnetic sensor using an ion-gated graphene field-effect transistor demonstrates a high current-normalized sensitivity larger than 3000 V/AT and low operation voltages smaller than 0.5 V. From commercially available graphene-on-SiO<SUB>2</SUB> wafers, large-area arrays of ion-gated graphene Hall element (ig-GHE) samples are prepared through complementary metal-oxide-semiconductor-compatible fabrication processes except the final addition of ionic liquid electrolyte covering the exposed graphene channel and the separate gate-electrode area. The enhanced carrier tunability by ionic gating enables this ig-GHE device to be extremely sensitive to magnetic fields in low-voltage-operation regimes. Further electrical characterization indicates that the operation window is limited by the nonuniform carrier concentration over the channel under high bias conditions. The drain-current-normalized magnetic resolution of the device measured using the low-frequency noise technique is comparable to the previously reported values despite its significant low power consumption.</P> [FIG OMISSION]</BR>

자율운전에 의한 계통연계형 도서의 저압 무순단 마이크로그리드 구축

김정헌(Jeong Hun Kim),권정민(Jung-Min Kwon),윤상윤(Sang-Yun Yun) 대한전기학회 2017 전기학회논문지 P Vol.66 No.4

This paper presents research on low-voltage microgrids to maintain a continuous power supply to critical loads on grid-connected islands in Korea. The low-voltage microgrids of this paper focused on that changes public office buildings into uninterrupted microgrids by autonomous operation. For this, a microgrid controller (MGC) and a power conditioning system (PCS) that allow a seamless transfer between grid-connected and grid-isolated operation are proposed. The proposed PCS operates with a silicon controlled rectifier (SCR) switch and employs a simple structure. It supplies power continuously without operators through a coordinated operation between MGC and PCS. In addition, proposed MG has a schedule operation for minimizing electricity charges and provides ancillary services that enable the utilization of resources according to the operation purpose of utility distribution networks. To demonstrate the uninterrupted low-voltage microgrid proposed in this study, a microgrid was implemented and tested in a public office building in Anjwa Island, Jeollanam-do in Korea. A seamless, autonomous operation history, despite system disturbances, was obtained through a long-term demonstration of operation. The results showed that the proposed microgrid technology can be used to achieve energy resilience in grid-connected island areas.

Maximum Efficiency Operation of Three-Level T-type Inverter for Low-Voltage and Low-Power Home Appliances

신승민,안정훈,이병국 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

This paper proposes a maximum efficiency operation strategy for three-level T-typeinverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areascompared with two-level inverter. The proposed strategy aims to operate in the maximum efficiencypoint for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzedin detail, and the two operation mode selection strategy is developed. The proposed algorithm isverified by theoretical analysis and experimental results.

Maximum Efficiency Operation of Three-Level T-type Inverter for Low-Voltage and Low-Power Home Appliances

Seung-Min Shin,Jung-Hoon Ahn,Byoung-Kuk Lee 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

This paper proposes a maximum efficiency operation strategy for three-level T-type inverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areas compared with two-level inverter. The proposed strategy aims to operate in the maximum efficiency point for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzed in detail, and the two operation mode selection strategy is developed. The proposed algorithm is verified by theoretical analysis and experimental results.

Maximum Efficiency Operation of Three-Level T-type Inverter for Low-Voltage and Low-Power Home Appliances

Shin, Seung-Min,Ahn, Jung-Hoon,Lee, Byoung-Kuk The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.2

This paper proposes a maximum efficiency operation strategy for three-level T-type inverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areas compared with two-level inverter. The proposed strategy aims to operate in the maximum efficiency point for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzed in detail, and the two operation mode selection strategy is developed. The proposed algorithm is verified by theoretical analysis and experimental results.

Organic Thin-Film Transistors Fabricated by Solution-Processed and Low-Temperature Condensed Hybrid Gate Dielectrics

Youngmin Song,Young-Geun Ha 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.2

Herein, we report on the preparation of new solution-processed and low-temperature condensed organic?inorganic hybrid dielectric films and their electrical properties for applications in low-power organic thin-film transistors (OTFTs). The low-temperature condensed hybrid dielectric films (~19?nm thick) were simply fabricated by spin coating a mixture solution of a zirconium chloride and synthesized bifunctional phosphonic acid organic reagents, followed by annealing at a relatively low temperature (~90?°C). The prepared hybrid dielectric films exhibited excellent dielectric properties (low leakage current density?<?10?6 A/cm2 and high capacitance of 520?nF/cm2) as well as a smooth surface (RMS roughness <0.3 nm). Consequently, the pentacene-based OTFTs were fabricated using these hybrid dielectrics and functioned effectively at a relatively low operating bias (?2 V) and exhibited great TFT characteristics (hole mobility: 0.3 cm2/V/s, low threshold voltage: ?0.7 V, low subthreshold swing: 0.17?V/dec, on/off current ratio: 105).

Full-Swing Local Bitline SRAM Architecture Based on the 22-nm FinFET Technology for Low-Voltage Operation

Kyoman Kang,Hanwool Jeong,Younghwi Yang,Juhyun Park,Kiryong Kim,Seong-Ook Jung IEEE 2016 IEEE transactions on very large scale integration Vol.24 No.4

<P>The previously proposed average-8T static random access memory (SRAM) has a competitive area and does not require a write-back scheme. In the case of an average-8T SRAM architecture, a full-swing local bitline (BL) that is connected to the gate of the read buffer can be achieved with a boosted wordline (WL) voltage. However, in the case of an average-8T SRAM based on an advanced technology, such as a 22-nm FinFET technology, where the variation in threshold voltage is large, the boosted WL voltage cannot be used, because it degrades the read stability of the SRAM. Thus, a full-swing local BL cannot be achieved, and the gate of the read buffer cannot be driven by the full supply voltage (V-DD), resulting in a considerably large read delay. To overcome the above disadvantage, in this paper, a differential SRAM architecture with a full-swing local BL is proposed. In the proposed SRAM architecture, full swing of the local BL is ensured by the use of cross-coupled pMOSs, and the gate of the read buffer is driven by a full V-DD, without the need for the boosted WL voltage. Various configurations of the proposed SRAM architecture, which stores multiple bits, are analyzed in terms of the minimum operating voltage and area per bit. The proposed SRAM that stores four bits in one block can achieve a minimum voltage of 0.42 V and a read delay that is 62.6 times lesser than that of the average-8T SRAM based on the 22-nm FinFET technology.</P>

Solution-Processable, Thin, and High-κ Dielectric Polyurea Gate Insulator with Strong Hydrogen Bonding for Low-Voltage Organic Thin-Film Transistors

Yoo, Sungmi,Kim, Dong-Gyun,Ha, Taewook,Chan Won, Jong,Jang, Kwang-Suk,Kim, Yun Ho American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.38

<P>We developed a solution-processable, thin, and high-dielectric polyurea-based organic gate insulator for low-voltage operation and high performance of organic thin-film transistors (OTFTs). A 60 nm-thick polyurea thin film exhibited a high dielectric constant of 5.82 and excellent electrical insulating properties owing to strong hydrogen bonding. The hydrogen bonding of the synthesized polyurea was confirmed using infrared spectroscopy and was quantitatively evaluated by measuring the interactive force using atomic force microscopy. Moreover, the effect of hydrogen bonding of polyurea on the insulating properties was systematically investigated through the combination of various monomers and control of the thickness of the polyurea film. The dinaphtho[2,3-<I>b</I>:2′,3′-<I>f</I>]thieno[3,2-<I>b</I>]thiophene-based OTFTs with the polyurea gate insulator showed excellent thin-film transistor (TFT) performance with a field-effect mobility of 1.390 cm<SUP>2</SUP>/V·s and an on/off ratio of ∼10<SUP>5</SUP> at a low operation voltage below 2 V. In addition, it is possible to fabricate flexible polymer organic semiconductor (OSC)-based TFT devices using a solution process, owing to excellent solvent stability in various organic solvents. We believe that the solution-processable polyurea gate insulator with a high dielectric constant and good insulation properties is a promising candidate for low-voltage-operated OTFTs using various OSCs.</P> [FIG OMISSION]</BR>