Implementation of an LED tile controller for high-quality image display

Ahn, Jin-Ho

doi:10.1016/j.displa.2012.10.004

Cited by 17 publications

(13 citation statements)

References 4 publications

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“…This EMI in the power supply is difficult to remove because of its high power and broad frequency spectrum (up to 100 MHz) [11]. Several techniques are used to overcome the EMI generated by the LED systems, including converter designs [12], components design [13], EMI filter [14], and spread-spectrum techniques [15]. However, all these methods increase the overall cost of the products and size of the PCB.…”

Section: Device Under Studymentioning

confidence: 99%

Electromagnetic Hotspots Identification in Integrated Circuits

Kapoor¹,

Sangwan²,

Tan³

2019

PIER Letters

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Advancements in functionalities and operating frequencies of integrated circuits lead to the necessity to study Electromagnetic Compatibility/Electromagnetic Emissions (EMC/EMEs) from these devices. In this work, a methodology is developed, which combines near field electromagnetic measurements and 3D layout simulation of an Integrated Circuit (IC), to identify the sources of EME from a commercial IC. This methodology can help to narrow down the area of key importance with respect to EME sources, instead of the entire IC, before it is fabricated. Consequently, IC designers can optimize their design to minimize the EME before fabrication, saving cost and time significantly.

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Section: Device Under Studymentioning

confidence: 99%

Electromagnetic Hotspots Identification in Integrated Circuits

Kapoor¹,

Sangwan²,

Tan³

2019

PIER Letters

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“…The measurement results show that the proposed timing can reduce the EMI by 14 dB while maintaining a constant current of 120 mA. The probabilistic PWM (PPWM) pulse generation using modified Linear Feedback Shift Register (LFSR) is proposed to address the EMI [32]. The emergence frequency, peak value, and variety of incoming currents can be reduced by the PPWM control that can effectively eliminate the problem The CPWM is proposed to suppress the EMI in high-power LED driver.…”

Section: Conducted Emi Mitigation In Led Drivermentioning

confidence: 99%

“…Various ways are used to overcome the EMI generated by the LED systems, including converter designs [12], [17]- [25], components design [26]- [29], the EMI filter [25], [30] and the spread-spectrum techniques [? ], [6], [11], [14], [31], [32]. However, the spread-spectrum technique is the most inexpensive and efficient solutions to mitigate the EMI.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Conducted EMI Mitigation on the LED Driver using Spread Spectrum Technique

Hidayat

Firmansyah

2016

International Journal of Electronics and Telecommunications

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Abstract-LED driver has the potential to interfere the system of electronic devices if the voltage and current change rapidly. Several previous studies presented various solutions to overcome this problem such as particular converter design, component design, electromagnetic interference (EMI) filters, and spreadspectrum techniques. Compared to other solutions, the spreadspectrum technique is the most potential way to reduce the EMI in LED applications due to its limited cost-size-weight. In this paper, the effectiveness of conducted EMI suppression performance and the evaluation of its effect on LED luminance using spreadspectrum techniques are investigated. Spread-spectrum is applied to the system by modifying the switching frequency by providing disturbances at pin IADJ. The disorder is given in the form of four signals, namely square, filtered-square, triangular, and sine disturbance signals. The highest level of the EMI suppression of about 31.89% is achieved when the LED driver is given 800 mVpp filtered-square waveform. The highest reduction power level occurs at fundamental frequency reference, when it is given 700 mVpp square disruption signal, is about 81.77% reduction. The LED luminance level will reduce by 85.2% when it is given the four waveforms disruption signals. These reductions occur as the switching frequency of the LED driver does not work on a fixed frequency, but it varies in certain bands. LED brightness level has a tendency to generate a constant value of 235 lux when it is given the disruption signals. This disturbance signal causes the dimming function on the system that does not work properly.

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“…Probabilistic PWM (PPWM) pulse generation using modified linear feedback shift register (LFSR) is proposed to address EMI [38]. The emergence frequency, peak value, and variety of incoming currents can be reduced by PPWM control, which is stochastic choose PWM pulse timing and control LEDs connected serially, can effectively eliminate the problem of temperature and EMI.…”

Section: Figure 1 Conducted Emission Cispr 22 Standardmentioning

confidence: 99%

The Effects of Spread-Spectrum Techniques in Mitigating Conducted EMI to LED Luminance

Hariyawan¹,

Hidayat²,

Firmansyah³

2016

IJECE

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Rapid voltage and current changes in recently ubiquitous LED driver have a potency to interfere other devices. Some solutions with special converter design, component design, EMI filter, and spread-spectrum techniques have been proposed. Due to cost-size-weight constraints, the spread-spectrum technique seems to be a potential candidate in alleviating EMI problem in LED application. In this paper, the effectiveness of conducted EMI suppression performance of the spread-spectrum technique is evaluated. Spread spectrum techniques applied by giving disturbance to the LED driver system with three profile signals, filtered square, triangular, and sine disturbance signal to the switching pattern of a buck LED driver topology. From the experiment results, 472.5 kHz triangular and 525 kHz sine signal can reduce EMI by 42 dB while the filtered square signal can reduce EMI 40.70 dB compared to fundamental constant-frequency reference 669 kHz. The filtered square signal can reduce the average power level better than other signal disturbance of 5.852618 dBµV. LED luminance decreases when the spread-spectrum technique is applied to the system. . To achieve high efficiency in energy transfer, switched-mode power supply (SMPS) topology is applied, such as buck, boost, flyback, cuk dan buck-boost [11]- [22]. In addition, the SMPS is widely applied due to the benefits offered in terms of size, weight, cost and performance. SMPS is usually implemented using pulse width modulation (PWM). PWM operates at a constant frequency. The weakness of this system is the fundamental and harmonic frequencies emitted through conducted and radiated mechanism. This emission is called electromagnetic interference (EMI). As a result, the potential converter does not meet the standards of electromagnetic compatibility (EMC) [11],[14][23], [24].SMPS has a periodic switching pattern, i.e. EMI spectrum which consists of the fundamental and harmonic frequencies with significant amplitudes up to the 20th harmonic [25]. This condition could probably pass the limit set by the conducted EMI CISPR 22 Class B standards. Some solutions are used to reduce EMI issues in LED drivers, including the converter designs [12] [39]. Of all these solutions, the spread-spectrum technique is a solution that is inexpensive and efficient in mitigating EMI.In this paper, conducted EMI mitigation is done by applying a spread-spectrum techniques in buck topology LED driver and observing its effect on the LED luminance. Spread spectrum techniques implemented by giving disturbance to the system with 3 profile of waveform signals, filtered square, triangle and sinusoidal waveform signals.

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Implementation of an LED tile controller for high-quality image display

Cited by 17 publications

References 4 publications

Electromagnetic Hotspots Identification in Integrated Circuits

Electromagnetic Hotspots Identification in Integrated Circuits

An Experimental Study of Conducted EMI Mitigation on the LED Driver using Spread Spectrum Technique

The Effects of Spread-Spectrum Techniques in Mitigating Conducted EMI to LED Luminance

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