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System identification of a building structure using wireless MEMS and PZT sensors
Kim, Hongjin,Kim, Whajung,Kim, Boung-Yong,Hwang, Jae-Seung Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.2
A structural monitoring system based on cheap and wireless monitoring system is investigated in this paper. Due to low-cost and low power consumption, micro-electro-mechanical system (MEMS) is suitable for wireless monitoring and the use of MEMS and wireless communication can reduce system cost and simplify the installation for structural health monitoring. For system identification using wireless MEMS, a finite element (FE) model updating method through correlation with the initial analytical model of the structure to the measured one is used. The system identification using wireless MEMS is evaluated experimentally using a three storey frame model. Identification results are compared to ones using data measured from traditional accelerometers and results indicate that the system identification using wireless MEMS estimates system parameters with reasonable accuracy. Another smart sensor considered in this paper for structural health monitoring is Lead Zirconate Titanate (PZT) which is a type of piezoelectric material. PZT patches have been applied for the health monitoring of structures owing to their simultaneous sensing/actuating capability. In this paper, the system identification for building structures by using PZT patches functioning as sensor only is presented. The FE model updating method is applied with the experimental data obtained using PZT patches, and the results are compared to ones obtained using wireless MEMS system. Results indicate that sensing by PZT patches yields reliable system identification results even though limited information is available.
High Power Efficiency, 8 V~20 V Input Range DC-DC Buck Converter with Phase-Locked Loop
HongJin Kim,Hyung-gu Park,Jae-hyung Jang,Young-Jun Park,YoungGun PU,Kang-Yoon Lee 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
This paper presents a DC-DC buck converter with Phase-Locked Loop (PLL) to generate the constant switching frequency regardless of Process, Voltage, Temperature (PVT) variations. When the input range is from 8 V to 20 V, the proposed DC-DC buck converter with PLL is implemented to have over 90 % efficiency in heavy load current of 1.0 A. also to reduce the size of the external device while maintaining high efficiency, 2 MHz switching frequency and 2.2 μH inductance were used. The proposed DC-DC buck converter with PLL to generate constant frequency to compensate for the efficiency variation. As a result, the efficiency variation is less than 1 %. This chip was fabricated using 0.18 μm BCD technology, and the area is 3.96 mm². The maximum efficiency of proposed DC-DC buck converter with PLL is 92.53 %.
An Inductive 2-D Position Detection IC With 99.8% Accuracy for Automotive EMR Gear Control System
Kim, SangYun,Abbasizadeh, Hamed,Ali, Imran,Kim, Hongjin,Cho, SungHun,Pu, YoungGun,Yoo, Sang-Sun,Lee, Minjae,Hwang, Keum Cheol,Yang, Youngoo,Lee, Kang-Yoon IEEE 2017 IEEE transactions on very large scale integration Vol.25 No.5
<P>In this paper, the analog front end (AFE) for an inductive position sensor in an automotive electromagnetic resonance gear control applications is presented. To improve the position detection accuracy, a coil driver with an automatic two-step impedance calibration is proposed which, despite the load variation, provides the desired driving capability by controlling the main driver size. Also, a time shared analog-todigital converter (ADC) is proposed to convert eight-phase signals while reducing the current consumption and area to 1/8 of the conventional structure. A relaxation oscillator with temperature compensation is proposed to generate a constant clock frequency in vehicle temperature conditions. This chip is fabricated using a 0.18-mu m CMOS process and the die area is 2 mm x 1.5 mm. The power consumption of the AFE is 23.1 mW from the supply voltage of 3.3 V to drive one transmitter (Tx) coil and eight receiver (Rx) coils. The measured position detection accuracy is greater than 99.8 %. The measurement of the Tx shows a driving capability higher than 35 mA with respect to the load change.</P>
System identification of a building structure using wireless MEMS and PZT sensors
Hongjin Kim,김화중,Boung-Yong Kim,황재승 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.2
A structural monitoring system based on cheap and wireless monitoring system is investigated in this paper. Due to low-cost and low power consumption, micro-electro-mechanical system (MEMS) is suitable for wireless monitoring and the use of MEMS and wireless communication can reduce system cost and simplify the installation for structural health monitoring. For system identification using wireless MEMS, a finite element (FE) model updating method through correlation with the initial analytical model of the structure to the measured one is used. The system identification using wireless MEMS is evaluated experimentally using a three storey frame model. Identification results are compared to ones using data measured from traditional accelerometers and results indicate that the system identification using wireless MEMS estimates system parameters with reasonable accuracy. Another smart sensor considered in this paper for structural health monitoring is Lead Zirconate Titanate (PZT) which is a type of piezoelectric material. PZT patches have been applied for the health monitoring of structures owing to their simultaneous sensing/actuating capability. In this paper, the system identification for building structures by using PZT patches functioning as sensor only is presented. The FE model updating method is applied with the experimental data obtained using PZT patches, and the results are compared to ones obtained using wireless MEMS system. Results indicate that sensing by PZT patches yields reliable system identification results even though limited information is available.
A Low Power, Small Area Cyclic Time-to-Digital Converter in All-Digital PLL for DVB-S2 Application
Kim, Hongjin,Kim, SoYoung,Lee, Kang-Yoon The Institute of Electronics and Information Engin 2013 Journal of semiconductor technology and science Vol.13 No.2
In this paper, a low power, small area cyclic time-to-digital converter in All-Digital PLL for DVB-S2 application is presented. Coarse and fine TDC stages in the two-step TDC are shared to reduce the area and the current consumption maintaining the resolution since the area of the TDC is dominant in the ADPLL. It is implemented in a 0.13 ${\mu}m$ CMOS process with a die area of 0.12 $mm^2$. The power consumption is 2.4 mW at a 1.2 V supply voltage. Furthermore, the resolution and input frequency of the TDC are 5 ps and 25 MHz, respectively.