High-Efficiency DC–DC Converter With Twin Bus for Dimmable LED Lighting

Self Cite

SUMMARYIn this paper, a single-stage integrated bridgeless AC/DC converter is proposed. As compared to its counterpart that is composed of totem-pole boost power factor correction (PFC) cascade fly-back DC/DC converter, the studied circuit has less components number while overcoming the limits of the totem-pole type. Thus, it is suitable to the low-power LED lighting applications. Furthermore, when both PFC inductors L b and magmatic inductance L m of the transformer TR1 operate at discontinuous current mode, the bus voltage v CB can be used to decouple the ac input and constant dc output power. Thus, the approach of increasing bus voltage ripple is employed to eliminate electrolytic capacitors and obtain long operation lifetime. Additionally, it is able to be compatible with our studied twin-bus configuration for increasing the overall efficiency. A 50-W hardware prototype has been designed, fabricated, and tested in the laboratory to verify the proposed converter validity.

Section: Experimental Verificationmentioning

confidence: 99%

Section: Experimental Verificationmentioning

confidence: 99%

A single‐stage integrated bridgeless AC/DC converter for electrolytic capacitor‐less LED lighting applications

Zheng

et al. 2014

Self Cite

“…In LCD backlight applications, a very useful feature is dimming, which enables power savings and improves grayscale resolution. Many techniques for dimming a LED device have been introduced in the literature [1][2][3][4][5][6][7][8][9]. Currently, dimming-utilizing pulse-width modulation (PWM) is commonly used in the industry.…”

Section: Introductionmentioning

confidence: 99%

“…PWM dimming switches a LED device on/off alternately at a constant peak direct current (DC) value and controls the equivalent average current to decrease. The typical method to achieve PWM dimming is to use a series-controlled switch with a LED [7][8][9][10][11][12][13][14][15][16] as shown in Figure 1(a-b). However, the use of a series switch needs to sustain the voltage stress in the switching interval and produces more switching loss.…”

Section: Introductionmentioning

confidence: 99%

A simple LED driver with low dimming switch stress

Lin

Leng

Wang

2015

This paper aims to investigate the low dimming switch stress of a light-emitting diode (LED) driver. Most dimmable LED drivers contain a series dimming switch with a LED string to implement a pulse-width modulation-dimming function. However, this setup causes the dimming switch to suffer from high voltage stress in the dimming interval. To reduce the voltage stress of a dimming switch, a low switch stress scheme is presented. The dimming circuit is parallel with the LED string. Using proper arrangement and design of the parameters, the dimming circuit changes the feedback status, which results in the output driving voltage varying between a constant current and a fixed voltage operation. These two operating conditions also make the LED string turn on/off alternately and consequently and perform the dimming function. The dimming switch acts by altering the feedback path instead of cutting off the main power flow; hence, it does not need a power level switch. Details of the operating principles and design considerations are discussed in this study. A prototype boost converter was developed to verify the feasibility of the proposed low dimming switch stress LED driver.

“…Figure 1 shows several PWM dimming techniques proposed recently. Figure 1(a) shows the PWM enable dimming: Totally turn ON and OFF of the power stage [5][6][7], that means to shutdown the controller then whole converter is switched on and off alternately at high frequency to dim the lamp light. But the use of higher dimming frequency is limited by the dynamic response of the converter.…”

Section: Introductionmentioning

confidence: 99%

A cost‐effective PWM dimming method for LED lighting applications

Chiu

Lin

et al. 2013

This paper presents a novel cost-effective pulse-width-modulation (PWM) dimming method for light-emitting diode (LED) lighting applications. High efficiency, high power factor, circuit simplicity, and low cost can be achieved by a Flyback power factor correction converter with the studied adaptive PWM dimming method. The operation principles and design considerations of the proposed LED dimming method are analyzed and discussed. A 45 W laboratory prototype has been built and tested to verify the feasibility of the proposed scheme. adaptive function. From 20% to 100% load range, the conversion efficiency can be up to 0.92 and the power factor is up to 0.99. All functions are implemented by cost-effective commercial control IC. The experimental results of a laboratory prototype are shown to verify the feasibility of the proposed scheme.