• Journal of Power Electronics
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• v.18 no.3
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• pp.871-878
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• 2018

In this paper, the conducted EMI reduction performances of active feed-forward current-sensing current-actuation (CSCA) and voltage-sensing current-actuation (VSCA) filters for a three-phase induction motor drive system are evaluated by experiments. For comparison purposes, the conducted EMI (CM emission, DM emission and total emission) of a three-phase induction motor drive with a conventional CM choke, a conventional CM choke in series with an active VSCA filter, and an active CSCA filter (where the CM choke was modified and used as a sensing current transformer) were compared to the case of a system without any filter inserted. Experimental results show that the active CSCA and VSCA filters can improve the CM reduction performance of the conventional CM choke by about 5 dB especially at low-frequencies. However, for DM comparisons, it shows that there is no different between cases with and without filters inserted.

• ETRI Journal
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• v.29 no.1
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• pp.70-78
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• 2007

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1593-1599
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• 2017

This paper presents a multi-channel light-emitting diode (LED) driver IC with a current-mode current regulator. The proposed current regulator replaces resistors for current sensing with a sequentially controlled single current sensor and a single regulation loop for sensing and regulating all LED channel currents. This minimizes the current mismatch among the LED channels and increases voltage headroom or, equivalently, power efficiency. The proposed LED driver IC was fabricated in a $0.35-{\mu}m$ BCD 60-V high voltage process, and the chip area is $1.06mm^2$. The measured maximum power efficiency is 93.4 % from a 12-V input, and the inter-channel current error is smaller than as low as ${\pm}1.3%$ in overall operating region.

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.201-206
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• 2020

This paper presents a new method for controlling the current of lighting LEDs without current sensors. This method can be used as backup against LED current sensor faults. LED lighting requires a circuit with a constant current in order to maintain the same brightness when the ambient temperature changes. Therefore, we propose a new current estimation method to provide backup in case of current sensor faults based on the calculation of the inductor current. In the fabricated circuit, the average current changes from 144.03 mA to 155.97 mA when the ambient temperature changes from 0℃ to 60℃. The application of this study can enable the fabrication of a driving IC for LEDs in the form of a single chip without sensing resistors. This is expected to reduce the complexity of the peripheral circuit and enable precise feedback control.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1482-1482
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• 2003

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.115-115
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• 2009

Current sensing in power semiconductors involves sensing of over-current in order to protect the device from harsh conditions. This technique is one of the most important functions in stabilizing power semiconductor device modules. The Power MOSFET is very efficient method with low power consumption, fast sensing speed and accuracy. In this paper, we have analyzed the characteristics of proposed sense FET and optimized its electrical characteristics to apply conventional 40 V power MOSFET by numerical and simulation analysis. The proposed sense FET has the n-drift doping concentration $1.5\times10^{14}\;cm^{-3}$, size of $600\;{\mu}m^2$ with $4.5\;{\Omega}$, and off-state leakage current below $50\;{\mu}A$. We offer the layout of the proposed Power MOSFET to process actually. The offerd design and optimization methods are meaningful, which the methods can be applied to the power devices having various breakdown voltages for protection.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.12-16
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• 2009

Current sensing in power semiconductors involves sensing of over-current in order to protect the device from harsh conditions. This technique is one of the most important functions in stabilizing power semiconductor device modules. The sense FET is very efficient method with low power consumption, fast sensing speed and accuracy. In this paper, we have analyzed the characteristics of proposed sense FET and optimized its electrical characteristics to apply conventional 450 V power MOSFET by numerical and simulation analysis. The proposed sense FET has the n-drift doping concentration $1.5{\times}10^{14}cm^{-3}$, size of $600{\um}m^2$ with $4.5\;{\Omega}$, and off-state leakage current below $50{\mu}A$. We offer the layout of the proposed sense FET to process actually. The offerd design and optimization methods are meaningful, which the methods can be applied to the power devices having various breakdown voltages for protection.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.456-461
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• 2010

This study compares the criteria of earth leakage breakers (ELB) and analyzes the characteristics of an Igc-free ELB operated by an active component which is not misoperated by capacitive current. Even for the same ELB, the earth leakage current flowing through the human body is estimated to be differ greatly depending on the power source, voltage, location and status of contact, contact time duration, etc. Earth leakage breakers are classified based on the rated voltage, rated sensing current, rated operating time etc. Mounting and demounting of the existing equipment can be performed easily since an $I_{gc}$-free ELB is manufactured with the same structure as a conventional ELB. The rated operating current of a conventional and an $I_{gc}$-free ELB is 30mA, the sensing current is 25mA and the rated non-operating current is 15mA. In the analysis of non-operating current characteristics, the rated non-operating current of 15mA was satisfied up to a 20mA charging current in the conventional ELB, but does not satisfy the rated non-operating current as it operates when the resistive leakage current is lower than 15mA for a charging current exceeding 20mA. Also, the ELB is misoperated without a resistive leakage current when the charging current exceeded 25mA. However, the newly developed $I_{gc}$-free ELB satisfied the rated non-operating current even when the charging current was 60mA. Also, in comparison to the interrupting characteristics, it was confirmed that the charging current satisfying the rated non-operating current of the $I_{gc}$-free ELB was three times higher than that of the conventional ELB.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.359-359
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• 2011

This study reports the H2S gas sensing properties of CuO / ZnO nano-hetero structure bundle and the investigation of gas sensing mechanism. The 1-Dimensional ZnO nano-structure was synthesized by hydrothermal method and CuO / ZnO nano-heterostructures were prepared by photo chemical reaction. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectra confirmed a well-crystalline ZnO of hexagonal structure. In order to improve the H2S gas sensing properties, simple type of gas sensor was fabricated with ZnO nano-heterostructures, which were prepared by photo-chemical deposition of CuO on the ZnO nanorods bundle. The furnace type gas sensing system was used to characterize sensing properties with diluted H2S gas (50 ppm) balanced air at various operating temperature up to 500$^{\circ}C$. The H2S gas response of ZnO nanorods bundle sensor increased with increasing temperature, which is thought to be due to chemical reaction of nanorods with gas molecules. Through analysis of X-ray photoelectron spectroscopy (XPS), the sensing mechanism of ZnO nanorods bundle sensor was explained by well-known surface reaction between ZnO surface atoms and hydrogen sulfide. However at high sensing temperature, chemical conversion of ZnO nanorods becomes a dominant sensing mechanism in current system. Photo-chemically fabricated CuO/ZnO heteronanostructures show higher gas response and higher current level than ZnO nanorods bundle. The gas sensing mechanism of the heteronanostructure can be explained by the chemical conversion of sensing material through the reaction with H2S gas.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.361-378
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• 2012

Most of the current frequency hopping (FH) based dynamic spectrum access (DSA) methods concern a reactive channel access scheme with synchronous inter-channel spectrum sensing, i.e., FH is reactively triggered by the primary user (PU)'s return reported by spectrum sensing, and the PU channel to be switched to is assumed precisely just sensed or ready to be sensed, as if the inter-channel spectrum sensing moments are synchronous. However, the inter-channel spectrum sensing moments are more likely to be asynchronous, which risks PU suffering more interference. Moreover, the spectrum sensing is usually erroneous, which renders the problem more complex. To address this problem, we propose a proactive FH based DSA method against both erroneous spectrum sensing and asynchronous inter-channel spectrum sensing (moments). We term it as proactive DSA. The optimal FH sequence is obtained by dynamic programming. The complexity is also analyzed. Finally, the simulation results confirm the effectiveness of the proposed method.