Single soft switched isolated converter with constant output current for light emitting diode driver

Amini, Mohammad Reza; Emrani, Amin; Adib, Ehsan; Farzanehfard, Hosein

doi:10.1049/iet-pel.2013.0281

Cited by 16 publications

(6 citation statements)

References 16 publications

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“…The switching ICs keep the on-time or off-time in constant values or impose a limitation on them to implement the maximum switching frequency ( f swmax ). At this situation, as shown in (10)- (12) and Fig. 7, if the output voltage is not significantly smaller than the input voltage, the LED current treats the same as the condition that the frequency limitation is not performed because the oscillation current amplitude is significantly smaller than its first negative peak value of oscillation.…”

Section: Resultsmentioning

confidence: 99%

“…Efficiency and power loss analyses of buck-flyback LED drivers were conducted in [9], which can be extended for other types of LED drivers. Some researchers used resonant circuits to increase the efficiency of LED drivers, in which power switches work on zero voltage and/or zero current switching (ZCS) [10][11][12]. One of the most popular methods in using the resonance to enhance the efficiency of the LED driver is the valley switching method [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Semi‐valley switching method for buck LED driver to increase its efficiency and performance

Sangrody

Marzband

et al. 2020

IET Power Electronics

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Valley switching is one of the most efficient methods to decrease the switching losses in DC/DC converters. It uses a resonance between the converter's inductor and parasitic output capacitance of a metal-oxide-semiconductor field-effect transistor. In this study, the drawbacks of the valley switching in buck light-emitting-diode (LED) drivers are investigated. It shows that in spite of decreasing the switching losses, the valley switching method reduces its efficiency in some conditions. Also, it is clarified that the valley switching method not only causes current fluctuation in boost power factor correction converters but also malfunctions the buck LED drivers' performance. In this study, a semi-valley switching and its implementation are introduced to solve these problems. In general, it is shown that the proposed method improves both the efficiency and the performance of the buck LED driver, simultaneously. The methodologies are implemented in an experimental prototype to verify the proposed method.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Semi‐valley switching method for buck LED driver to increase its efficiency and performance

Sangrody

Marzband

et al. 2020

IET Power Electronics

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“…Power supplies with constant current control are widely used in adapters, LED lighting, chargers, etc. 1,2 In small power applications, primary-side regulation (PSR) flyback converter is very popular. It eliminates the opt-coupler and provides significant advantages such as higher power density, lower cost, and smaller standby power.…”

Section: Introductionmentioning

confidence: 99%

A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

Wang

Kou

et al. 2018

Circuit Theory & Apps

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Primary-side regulation (PSR) flyback converter is widely used in small power applications. To increase the output power, continuous conduction modulation mode is always introduced. In this paper, a simple average current control method with very low cost is proposed for constant current controlled PSR flyback converter in both continuous conduction modulation mode and discontinuous conduction modulation mode. The average current control method is realized with time-length equality by simply comparing the average current with switch current, such that analog-to-digital converter for current sampling in traditional average current control method is removed. In addition, to eliminate the subharmonic oscillation and keep low cost, a fixed switch-off time control with time-length compensation algorithm is used. To improve the output current accuracy, a hysteretic multimode control method is applied. The total control requires very low implementation costs that only contain a lowspeed Digital to analog converter (DAC), three comparators, and a digital controller. The performance of the proposed control method is experimentally verified on an Field-progrannable gate array (FPGA) controlled 3.8 to 16 V/3.8 A PSR flyback converter. In experiments, stable control and high output current accuracy are obtained, and the output current accuracy is within ±1.8% under universe line voltage and output load.

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“…Light-emitting diode (LED) is the typical LCD backlight source. LED is typically driven by constant current [1][2][3][4] to protect the LED modules and obtain the expected brightness. The maximum current rating of each LED module is limited because of thermal limitations.…”

Section: Introductionmentioning

confidence: 99%

Light‐emitting diode driver with a combined energy transfer inductor for current balancing control

Lin

Chiu

et al. 2015

IET Power Electronics

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This study proposes a two-channel light-emitting diode (LED) backlight driver specifically for liquid crystal display monitor application that utilises an integrated magnetic component: a combined energy transfer inductor for current balancing. The integrated magnetic component has two functions: as a boost inductor and as a differentialmode current balance transformer. Under proper design and arrangement, all of the windings are wound on a single UU-core. This scheme uses leakage inductance as boost inductor for energy transfer and mutual inductance as differential mode transformer for output current balancing. By introducing the magnetic component, power density is increased whereas the overall cost and volume of the magnetic components are reduced in comparison with those values under conventional topology. The operating principles and design considerations of the proposed LED driver were analysed. A 10 W prototype converter with a two-channel LED string was developed to verify the feasibility of the proposed driver. Experimental results show that the proposed LED driver provides an equal current for a two-channel LED string.

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Single soft switched isolated converter with constant output current for light emitting diode driver

Cited by 16 publications

References 16 publications

Semi‐valley switching method for buck LED driver to increase its efficiency and performance

Semi‐valley switching method for buck LED driver to increase its efficiency and performance

A simple average current control with time‐length equality for primary‐side regulation flyback converter with constant output current control

Light‐emitting diode driver with a combined energy transfer inductor for current balancing control

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