• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.581-582
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• 2010

This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 step by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.402-403
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• 2009

A variety of power reduction technologies is introduced and the benefits of the technologies are discussed. PenTile$^{(R)}$ DBLC (Dynamic Brightness LED Control) combined with SABC (Sensor-Based Adaptive Brightness Control) enables to achieve the average LED power consumption to one third. The panel power reduction of 25% can be achieved with low power driving technology, ALS (Active Level Shifter). MIP (Memory In Pixel) is expected to be useful in transflective display because the whole display area can be utilized in reflective mode with power consumption of 1mW.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.261-263
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• 2004

This paper studies the lighting pattern control of a high-brightness LED warning light. The driving circuit for the warning light is composed of a full-wave rectified circuit and of a control circuit using a micro-controller (AT89c2051). The micro-controller is programmed in a suitable manner to accomodate a number of variable lighting patterns and to adjust the blinking speed. To reduce the total number of LEDs installed a special consideration is made to the bundled pattern in a lamp module which is lit simultaneously. The resultant LED warning light has merits not only over the conventional incandescent warning light on the energy saving aspect but also over some other LED-type ones in the market.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.218-220
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• 2008

This paper describes buck converter's MOSFET driver for high-brightness LED strings. The power driving high-side MOSFET is supplied from the power source of control circuit part. The practical considerations and future work are also described.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.593-600
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• 2010

In this paper, High brightness LED (light-emitting diodes) driver IC (integrated circuit) using new current sensing circuit is proposed. This LED driver IC can provide a constant current with high current precision over a wide input voltage range. The proposed current-sensing circuit is composed of a cascode current sensor and a current comparator with only one reference voltage. This IC minimizes the voltage stress of the MOSFET (metal oxide semiconductor field effect transistor) from the maximum input voltage and has low power consumption and chip area by using simple-structured comparator and minimum bias current. To confirm the functioning and characteristics of our proposed LED driver IC, we designed a buck converter. The LED current ripple of the designed IC is in ${\pm}5%$ and a tolerance of the average LED current is lower than 2.43%. This shows much improved feature than the previous method. Also, protections for input voltage and operating temperature are designed to improve the reliability of the designed IC. Designed LED driver IC uses 1.0 ${\mu}m$ X-Fab. BiCMOS process parameters and electrical characteristics and functioning are verified by spectre (Cadence) simulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.512-513
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• 2008

The study examined what effects 100kHz PWM LED light irradiation causes to bone marrow cells of SD-Rat when LED characterized cheap and safe is used onto the light therapy by replacing the low 1evel laser. We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Consequent1y, the current value could be controlled by the change of 1eve1 in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of Rat bone marrow cells was verified in 100kHz PWM LED light irradiation group as compared to non-irradiation group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04b
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• pp.10-11
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• 2008

We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. And then, each experiment was performed to irradiation group and non-irradiation group for bone marrow cells. MIT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of bone marrow cells was verified in irradiation group as compared to non-irradiation group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.480-480
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• 2007

This paper performed the basic study for developing the light therapy equipment for medical treatment. We developed the equipment for medical therapy using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, and to control the change of output value, TLC5941 was used. Control stage is divided into 4 step by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and the output of a high brightness LED could be controlled, stage by stage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2280-2288
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• 2014

The conventional dimming control methods of LED (Light-emitting dioades) include Analog, PWM (Pulse Width Modulation), and FM (Frequency Modulation) Control. Analog dimming is controlled by adjusting forward current of Power LED. Although Analog dimming is possible to control linearly the brightness levels on a whole range (0%~100%), it comes into existence a variation of wavelength by changing the Power LED's forward current. PWM dimming has achieved by varying in duty of full current flowing to the Power LED. Generally, PWM dimming doesn't make variation of wavelength but have difficulty with adjusting the linear brightness level between 0% and 10%. FM dimming method is on the same wavelength as PWM dimming, however, it has problem of flickering at low level of dimming. This paper propose a efficient dimming control method of Power LED in order to overcome the disadvantages of the above mentioned methods. We apply to Analog method in low level of dimming control and use PWM method in dimming range from 10% to 100%. For the experiment, we design and implement a circuit and test the proposed method. Consequently, we can control the linear brightness of Power LED across the whole range and get the constant wave at different dimming level. The experimental results show the benefits of the proposed method.

• Smart Media Journal
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• v.8 no.3
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• pp.47-52
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• 2019

In this paper, we designed HW / SW interfaces for processing the signals of capacitive sensors like Electric Potential Sensor (EPS) to detect the surrounding electric field disturbance as feature signals in motion recognition systems. We implemented a smart light control system with those interfaces. In the system, the on/off switch and brightness adjustment are controlled by hand gestures using the designed and fabricated interface circuits. PWM (Pulse Width Modulation) signals of the controller with a driver IC are used to drive the LED and to control the brightness and on/off operation. Using the hand-gesture signals obtained through EPS sensors and the interface HW/SW, we can not only construct a gesture instructing system but also accomplish the faster recognition speed by developing dedicated interface hardware including control circuitry. Finally, using the proposed hand-gesture recognition and signal processing methods, the light control module was also designed and implemented. The experimental result shows that the smart light control system can control the LED module properly by accurate motion detection and gesture classification.