2016 iMiD, Jeju, Republic of Korea

August 24 - 26, 2016 (Wed - Fri), ICC Jeju

<Oral Session : 60. Driving Circuit and Panel Design>

Low-Dropout Regulator based on a-InGaZnO Thin-Film Transistor for Display Driving Systems

Yongchan Kim, Hojin Lee

Abstract

Among various thin-film transistor (TFT) technologies developed so far for integrating the display driving system onto TFT arrays and, therefore, to eliminate the IC assembly, amorphous Indium-Gallium-Zinc-Oxide (a-InGaZnO) TFTs have shown favorable electrical characteristics to achieving the integrated driving circuitry. Previously, we had demonstrated a fully adaptive DC-DC converter circuit could be built with a-InGaZnO TFT based operational amplifier (op-amp). However, in order to make the adaptive DC-DC converter functional, it required an external circuit block made of commercial passive devices on a printed circuit board (PCB). Different from the reported DC-DC converter, Low-Dropout (LDO) regulators are well known to have simple structures with small occupied area, accurate output voltages, and low output ripples. In this paper, we designed a fully integrated LDO regulator on glass substrate for supplying the designated power to display systems.

2016 CLEO: 2016, San Jose, USA

June 5 - 10, 2016 (Sun - Fri), San Jose Convention Center

<Poster Session : BB3-32>

Focusing of Terahertz Waves by Self-Complementary Meta-Atom toward Electromagnetically Induced Transparency

Hyunseung Jung¹, Chihun In², Hyunyong Choi², Hojin Lee¹

Abstract

Metamaterial analogues of electromagnetically induced transparency (EIT) have recently attracted worldwide researchers to realize intriguing applications such as slow light devices and nonlinear optics [1, 2]. However, conventional EIT analogues could be generated only by the destructive interference between asymmetrically arranged radiative (bright) and non-radiative (dark) atoms to produce the sharp transmission window within the broad reflection band. In this work, we studied a new way to achieve EIT-like spectral properties from a single self-complimentary meta-atom (SCM) by integrating cut-wire (CW) pair with a pseudo-complimentary cut-wire (p-CCW) structure within a unit cell. Different from the conventional EIT analogues, electric field (E-field) was highly enhanced and focused at edges of the hole and EIT-like properties are generated in the proposed SCM structure.

2016 APCCAS, Jeju, Republic of Korea

October 25 - 28, 2016 (Tue - Fri), Ramada Plaza Jeju Hotel

<Special Session : Display Driver Interface Circuits>

Design of Low-Dropout Regulator Using a-InGaZnO Thin-Film Transistors

Yongchan Kim, Hojin Lee

Abstract

In this paper, we presented a low-dropout (LDO) regulator composed with amorphous indium-gallium-zinc-oxide thin-film transistors (a-InGaZnO TFTs) for display driving systems. Through extensive simulation works, we confirmed that the proposed LDO regulator successfully could control the output voltage levels to follow the reference input voltages, and the output voltage ripple could be suppressed below 48mV when input reference voltage was changed from 14V to 15V with 100mV fluctuation.

2016 APCCAS, Jeju, Republic of Korea

October 25 - 28, 2016 (Tue - Fri), Ramada Plaza Jeju Hotel

<Special Session : Display Driver Interface Circuits>

On-Glass Operational Amplifier using Solution-Processed a-IGZO TFTs

Daejung Kim, Keun-Yeong Choi, Hojin Lee

Abstract

In this paper, we presented a novel operational amplifier (op-amp) only with solution-processed n-type amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFTs and common-source amplifier were fabricated on glass substrate through the solution process and confirmed to show stable electrical characteristics suitable for display driving circuits. Based on the experimental results, we designed an op-amp to have an overall gain of 30.5 dB, a cut-off frequency of 1.47 kHz, and a unit gain frequency of 6.65 kHz when supply voltage was ±15 V. Finally, by constituting the comparator, the proposed op-amp is expected to be used in power control and driving systems for display applications.

2015 MRS Spring Meeting, San Francisco, USA

April 6 - 10, 2015 (Mon - Fri), Moscone West Center