• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.174-184
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• 2013

For the successful R&D and deployment of LED-based green energy lighting systems, the real-time power quality measurement of both various non-linear power signals including pulse waveform, spike waveform, etc and the undesired-signals including harmonics, sag, swell, etc is required. In this paper, we propose a low-cost power quality measurement (PQM) method for low- (60Hz-several KHz) to high-frequency (several tens KHz) power signals, which are generated by green-energy lighting systems, and implement a PQM testbed using TI TMS320F28335 MCU. The proposed algorithm is programmed using C in the CCS (Code Composer Studio) 3.3 environment and is verified using test signals generated by an arbitrary signal generator, NF-WF1974. In the implemented testbed, we can measure various non-linear current signals that LED SMPS generates, analyze harmonics by fast Fourier transform, and test sag, swell, and interruption using wavelet transform.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.128-135
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• 2013

This paper presents a high dimming ratio Power-LED driver IC with high power which is capable of controlling LEDs. In order to accomplish a high dimming ratio LED driver, the preloading inductor current methodology is proposed for the power stage of the proposed method to achieve the fast transient response time during the Power-LED load switching. The information containing the current flowing on the LEDs can be utilized to predict the amount of the current on the inductor. The minimum LED current rising time of existing high dimming ratio Power-LED driver is limited by $3{\mu}s$, however that of the proposed high dimming ratio Power-LED driver is reduced about 1/10. The LED driver is implemented with 0.35um 60V BCDMOS 2-poly 4-metal process. The measurement results show that the proposed LED driver system features the minimum rising time as small as 240ns at the dimming frequency of 1KHz with a 12V of input voltage, nine white LEDs and 353mA of LED current. The LED rising time and power conversion efficiency of the chip are measured to be 240ns and 93.72%, respectively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.586-592
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• 2018

In this paper, HIC with various functions is proposed for the design 140W LED power control circuit. The proposed HIC integrates constant voltage/constant current circuit, short circuit protection circuit, internal constant voltage circuit, and dimmer circuit, thereby reducing the horizontal length of the PCB by 16% comparing with the conventional system. Through various experiments, we verified the performance of each block implemented inside of HIC with numerical results. (Constant voltage variation ratio: 2.9%, dimmer circuit duty variation within 5%, stable short protection at 720 mA) Since the PCB area can be significantly reduced by applying the proposed HIC. It is possible to reduce the PCB manufacturing time which takes up most of the manufacturing time, however, It is expected that the faulted power module can be replaced without replacing the whole PCB, so that maintenance / repair can be made easier.

• Journal of IKEEE
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• v.26 no.3
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• pp.445-455
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• 2022

This paper presents the optimal design of flyback transformer with the flat copper winding method of injection type suitable for the small-size and winding method of automatic type used in 90W DC to DC converter for LED-TV. This paper also proposes the flyback transformer with the flat copper winding method of injection type capable of the winding method of automatic type and the reduction of transformer size and enhanced uniformity in electrical characteristics compared to the conventional mass-production flyback transformer with the winding method of manual type. In particular, the flat copper winding transformer of injection type proposed in this paper is constructed in a vertical winding method of its transformer to realize the winding method of automatic type. The primary and secondary windings of flyback transformer with the flat copper winding method of injection type used the conventional winding, triple insulated winding and the flat copper winding method of injection type, respectively. The optimal design of flyback transformer with the flat copper winding transformer of injection type proposed in this paper suitable for small-size and winding method of automatic type was carried out based on the simulation results using Maxwell 2D and 3D tool.