• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.330-336
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• 2007

A single pixel photon counting type image sensor which is applicable for medical diagnosis with digitally obtained image and industrial purpose has tern designed with $0.18{\mu}m$ triple-well CMOS process. The designed single pixel for readout chip is able to be operated by single supply voltage to simplify digital X-ray image sensor module and a preamplifier which is consist of folded cascode CMOS operational amplifier has been designed to enlarge signal voltage(${\Delta}Vs$), the output voltage of preamplifier. And an externally tunable threshold voltage generator circuit which generates threshold voltage in the readout chip has been newly proposed against the conventional external threshold voltage supply. In addition, A dark current compensation circuit for reducing dark current noise from photo diode is proposed and 15bit LFSR(Linear Feedback Shift Resister) Counter which is able to have high counting frequency and small layout area is designed.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.197-199
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• 2006

This paper proposes the method to improve the charging speed of high voltage capacitor used in the medical device with high voltage. Feedback control method with microprocessor was used to detect and control the charging voltage. The result shows that the proposed method is more efficient than the previous converting method with typical PWM IC.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.325-329
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• 2000

An effective Carrier-Based PWM scheme that enables the instantaneous quality of each branch point voltage of a diode clamped 4-level inverter to be reduced at a low modulation index is described. This scheme presents a computed zero sequence voltage of PWM by the feedback of both DC-link voltages and load currents. The proposed PWM scheme enables to increase the controllable region of DC-link voltage and makes it possible to operate with small DC-link capacitors. The validity of the proposed PWM scheme is verified by simulation results.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.215-217
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• 2007

This paper proposes the method to improve the charging speed of high voltage capacitor used in the portable medical device. The feedback control method with microprocessor was used to detect charging time and control charging voltage. The result shows that the proposed method is more efficient than only voltage check method with typical charging sequence control.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.53-60
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• 2010

This paper presents a novel gain control system composed of a feedback circuit, Two stage Low Noise Amplifier (LNA) using 0.18 um CMOS technology for 5.2 GHz. The feedback circuit consists of the seven function blocks: peak detector, comparator, ADC, IVE(Initial Voltage Elimination) circuit, switch, storage, and current controller. We focus on detecting signal and designing storage circuit that store the previous state. The power consumption of the feedback circuit in the system can be reduced without sacrificing the gain by inserting the storage circuit. The adaptive front-end system with the feedback circuit exhibits 11.39~22.74 dB gain, and has excellent noise performance at high gain mode. Variable gain LNA consumes 5.68~6.75 mW from a 1.8 V supply voltage.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.245-248
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• 2000

In this paper a novel method for voltage disturbance detection is presented. This is a instantaneous detection method using normalized error get in synchronous reference frame and also it is implemented in digital. Feedback noise the problem of digital implementation is removed by a digital filter of which the time delay is compensated through numerical analysis.

• Journal of IKEEE
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• v.24 no.4
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• pp.1162-1166
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• 2020

In this paper Low Drop-Out (LDO) regulator that improved load regulation characteristics due to the feedback detection structure. The proposed feedback sensing circuit is added between the output of the LDO's internal error amplifier and the input of the pass transistor to improve the regulation of the delta value coming into the output. It has a voltage value with improved load regulation characteristics than existing LDO regulator. The proposed LDO structure was analyzed in Samsung 0.13um process using Cadence's Virtuoso, Spectre simulator.

• Journal of Power Electronics
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• v.15 no.1
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• pp.268-277
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• 2015

In this paper, a dual-converter three-phase pulse width modulation (PWM) rectifier based on unbalanced one-cycle control (OCC) strategy is proposed. The proposed rectifier is used to eliminate the second harmonic waves of DC voltage and distortion of line currents under unbalanced input grid voltage conditions. The dual-converter PWM rectifier employs two converters, which are called positive-sequence converter and negative-sequence converter. The unbalanced OCC system compensates feedback currents of positive-sequence converter via grid negative-sequence voltages, as well as compensates feedback currents of negative-sequence converter via grid positive-sequence voltages. The AC currents of positive- and negative-sequence converter are controlled to be symmetrical. Thus, the workload of every switching device of converter is balanced. Only one conventional PI controller is adopted to achieve invariant power control. Then, the parameter tuning is simplified, and the extraction for positive- and negative-sequence currents is not needed anymore. The effectiveness and the viability of the control strategy are demonstrated through detailed experimental verification.

• Journal of Power Electronics
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• v.11 no.5
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• pp.743-750
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• 2011

This article deals with the sensor-less control of a DC Motor via a SEPIC Converter-Full Bridge combination powered through solar panels. We simultaneously regulate, both, the output voltage of the SEPIC-converter to a value larger than the solar panel output voltage, and the shaft angular velocity, in any of the turning senses, so that it tracks a pre-specified constant reference. The main result of our proposed control scheme is an efficient linear controller obtained via Lyapunov. This controller is based on measurements of the converter currents and voltages, and the DC motor armature current. The control law is derived using an exact stabilization error dynamics model, from which a static linear passive feedback control law is derived. All values of the constant references are parameterized in terms of the equilibrium point of the multivariable system: the SEPIC converter desired output voltage, the solar panel output voltage at its Maximun Power Point (MPP), and the DC motor desired constant angular velocity. The switched control realization of the designed average continuous feedback control law is accomplished by means of a, discrete-valued, Pulse Width Modulation (PWM). Experimental results are presented demonstrating the viability of our proposal.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1177-1182
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• 2018

We designed a 500W zero voltage switching DC / DC converter operating at 100Mhz with phase shift topology using UCC3895 driver. The dead time of the UCC3895 driver is designed so that the leading and lagging leg of the full bridge can be driven separately. So, the dead time can be given between the two legs separately. The dead time, which is an asymmetrical relationship between the two legs, enables the implementation of zero voltage switching. This paper proposed a negative feedback circuit design method for stable output voltage. The maximum efficiency of the prototype was 95.5% at $500{\Omega}$ load.