Woong Choi

Dr. Woong Choi

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 December 2020 in IEEE Journal of Solid-State Circuits
Verified
Journal Article
Closed access
KLKyeongho Lee
Kyeongho Lee
WCWoong Choi
Woong Choi
Jongsun ParkJongsun Park
Jongsun Park
This article presents an adaptive match-line (ML) discharge scheme for low-power, high-performance, and compact ternary content addressable memory (TCAM). In the proposed TCAM, the transposed cell topology enables the selectively controlled ML pull-down path and compact array area. By employing the adaptive ML discharge and ML boosting scheme, unnecessary ML discharge and redundant search-line (SL) switching are eliminated for low-cost TCAM search operation. In order to minimize ML voltage swing at a wide voltage range, a timing calibration scheme is also adopted in the proposed TCAM. A 128 $\times $ 64 test chip implemented with 65-nm CMOS technology shows that the proposed adaptive ML discharge improves up to 69% of search delay and saves 37% of search energy compared with the conventional approach at 1.1 V, 100 MHz. The measurement result shows energy efficiency of 0.6 fJ/bit/search and 8% improvement of figure-of-merit (FoM) (energy/bit/search) compared with the state-of-the-art works.

28 June 2024 in IEEE Transactions on Power Electronics
Verified
Journal Article
Closed access
YJYoung-Jun Jeon
Young-Jun Jeon
HJHyun-Woo Jeong
Hyun-Woo Jeong
HPHyeonho Park
Hyeonho Park
JEEYOUNG ShinJEEYOUNG Shin
JEEYOUNG Shin
JJJunwon Jeong
Junwon Jeong
SHSung-Wan Hong
Sung-Wan Hong
This letter proposes an n-type output capacitorless low-dropout regulator (LDO) with high power supply rejection (PSR) and fast transient response. To enhance both the performances, a multiple-feedback loop structure is proposed. The LDO obtained a PSR of –40 dB (–25 dB) at 1 MHz with load currents of 100 mA (600 mA). The LDO achieved an undershoot of 116 mV when the load changes from 1 to 600 mA, while consuming a quiescent current of 27.5 μA. The chip was fabricated in the 180-nm CMOS process with an area of 0.063 mm 2 .

1 December 2018 in Measurement
Verified
Journal Article
Closed access
YLYongseok Lim
Yongseok Lim
WCWoong Choi
Woong Choi
YPYongju Park
Yongju Park
SOSangwook Oh
Sangwook Oh
YKYounghun Kim
Younghun Kim
Jongsun ParkJongsun Park
Jongsun Park

24 October 2019 in IEEE Transactions on Power Electronics
Verified
Journal Article
Closed access
JPJieun Park
Jieun Park
Hyung-Min LeeHyung-Min Lee
Hyung-Min Lee
SSSe-Un Shin
Se-Un Shin
WCWoong Choi
Woong Choi
SHSung-Wan Hong
Sung-Wan Hong

29 August 2022 in IEEE Transactions on Circuits and Systems II: Express Briefs
Verified
Journal Article
Closed access
MSMinseob Shim
Minseob Shim
JJJunwon Jeong
Junwon Jeong
JSJunyoung Song
Junyoung Song
YKYongtae Kim
Yongtae Kim
WCWoong Choi
Woong Choi
This paper presents a segmented match-line (ML) and charge-sharing based search scheme for low-cost ternary contents addressable memory (TCAM). In the proposed TCAM, a first-round search operation is performed on half cells located in even columns. During the first-round search, most of the mismatch cases are filtered out while remaining few mismatched cases that is misrecognized as the matched case. To complete the search operation in a low-power manner, a charge-sharing between the segmented MLs is used for the second-round search operation. The proposed 16KB 16T-NOR TCAM macro has been implemented using a 28nm CMOS technology. Numerical results show that the proposed TCAM improves sensing delay up to 5.6x faster and saves search energy-delay-product by 83% compared to the conventional approaches.

27 November 2021 in Electronics
Verified
Journal Article
Open access
PDF file
SKSunhee Kim
Sunhee Kim
WCWoong Choi
Woong Choi
YLYongseok Lim
Yongseok Lim
Recently, wireless charging technologies for large moving objects, such as electric vehicles and robots, have been actively researched. The power transmitting and receiving coils in most large moving objects are structurally separated by a given distance, which exposes a high output power to the outside world. If a foreign metal object enters the area between these two coils during wireless power transfer, fire hazards or equipment damage may occur. Therefore, we propose a method for detecting foreign metal objects in the gap between the transmitting and receiving coils in a wireless high-power transfer system. A resonant detection coil set is used to exploit the change induced in electrical characteristics when a foreign metal object is inserted. The mutual inductance of the foreign metal object changes the impedance of the detection coil set. We developed a simple circuit to detect both the magnitude and phase change of the voltage signal according to the altered impedance. Additionally, we implemented a prototype of a wireless power transfer system with a detection system to verify that even small foreign metal objects can be detected effectively.