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1.
A single‐stage integrated bridgeless AC/DC converter for electrolytic capacitor‐less LED lighting applications 下载免费PDF全文
Hongbo Ma Cong Zheng Wensong Yu Jih‐Sheng Lai 《International Journal of Circuit Theory and Applications》2015,43(6):742-755
In 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 Lb and magmatic inductance Lm of the transformer TR1 operate at discontinuous current mode, the bus voltage vCB 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. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Mitsuhiro Kadota Hiroyuki Shoji Atsushi Hatakeyama Keiji Wada 《Electrical Engineering in Japan》2019,209(3-4):26-34
This article proposes an LED driver that consists of a ceramic‐capacitor‐input rectifier and a buck‐boost converter. The LED driver has an advantage of long life because it does not contain any electrolytic capacitors. However, the issue with electrolytic capacitor‐less LED driver is that the ripple of the smoothed voltage becomes large due to insufficient capacitance of the smoothing capacitor. The proposed method, which uses the discontinuous current mode of a buck‐boost converter, reduces the output current ripple under such conditions. Experimental results using a 5.7 W LED driver prototype demonstrate that the proposed method reduces the output current ripple and that the percent flicker becomes 4.4%, which is smaller than the recommended upper limit of 8%. 相似文献
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Jian‐Min Wang Sen‐Tung Wu Shang‐Chin Yen Jing‐Yuan Lin 《International Journal of Circuit Theory and Applications》2015,43(12):1879-1898
This study proposes a simple control scheme for using single‐stage flyback (SSF) converters in lighting source applications for LEDs. Among the advantages of the average current mode is an I/O current ripple that is only one‐half of the critical conduction mode (CRM). This condition helps extend the output capacitor lifetime while lowering the input EMI capacitance input EMI capacitance. The SSF converter proposed in this study operates in continuous conduction mode (CCM). In addition, two sample‐and‐hold (S/H) circuits are placed at the output voltage loop and feed‐forward path, respectively. Since these S/H circuits access the average output current and average feed‐forward voltage, the LED driver is unaffected by the 120‐Hz ripple noise, the total harmonic distortion (THD) is reduced, and the transient response of the output current is improved. Finally, the operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Po‐Yen Chen Ching‐Tsai Pan Yi‐Hua Liu 《International Journal of Circuit Theory and Applications》2016,44(12):2058-2071
In this paper, a novel single stage passive ac to dc converter is first proposed for LED drivers. No controlled active switch, electrolytic capacitors and auxiliary power supply are required in the proposed LED driver. The advantages of the proposed driver include long lifetime, high efficiency and recyclability. In addition, application of the proposed quasi‐resonant circuit enables one to use much smaller capacitance and inductance for the capacitors and inductor to achieve high power factor and compact size. Theoretical analysis of the proposed LED driver is made, and some design guidelines are provided. Finally, a prototype system of 50‐W rating is constructed. Experimental results confirm the validity of the proposed LED driver. It can be seen that the proposed driver is robust to variations of input voltage, frequency and output load. The features of low cost, long lifetime, robustness and without EMI problem render the proposed driver a very attractive alternative for outdoor applications. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Huang‐Jen Chiu Hsiu‐Ming Huang Hong‐Tzer Yang Shih‐Jen Cheng 《International Journal of Circuit Theory and Applications》2008,36(2):205-210
This paper presents a high‐performance LED lamp driver with an improved single‐stage Flyback configuration. A constant current control method is used to regulate the lamp current and brightness. A laboratory prototype has been built and tested. With the prototype, high efficiency, high power factor, and constant lamp current can be achieved under different pieces of LED series connection. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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A systematic approach to designing a wide‐current range,MOS capacitor‐based switched‐capacitor DC‐DC converter with an augmenting LDO 下载免费PDF全文
Hakan Dogan Shady A. El‐Sayed Mohammed 《International Journal of Circuit Theory and Applications》2018,46(3):468-482
Switched‐capacitor DC‐DC converters (SC DC‐DC) are analyzed for loss sources, voltage regulation integrity, start‐up latency, and ripple size, while the trade‐offs between these metrics are derived. These analyses are used to design a SC DC‐DC that achieves high efficiency in a wide load current range. Four‐way interleaving was employed to reduce the output ripple and efficiency loss due to this ripple. The design can be reconfigured to achieve gains of 1/3 and 2/5 for inputs ranging between 1.4 and 3.6 V to generate output voltage range of 0.4 to 1.27 V and can supply peak load current of 22 mA. It uses thin‐oxide MOS capacitors for their high density and achieves 75.4% peak efficiency with an input frequency of 100 MHz and a load capacitor of 10 nF. An augmenting LDO that only regulates during sudden load transients helps the converter respond fast to these transients. The chip was implemented using a 65‐nm standard CMOS process. 相似文献
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Xiaohui Qu Siu‐Chung Wong Chi K. Tse 《International Journal of Circuit Theory and Applications》2012,40(8):759-775
To emit high‐quality LED light, one or a bin of LED lamp(s) is normally driven by a PWM‐controlled constant current source to minimize device variation and achieve accurate brightness control. Powered from offline AC mains, the front‐end power converters should provide a relatively low DC voltage bus for the inputs of post‐end LED current regulators. To match the long lifetime of LEDs, the whole LED driver (ballast) should work as durably as the LEDs. However, the lifetime of the driver is usually limited by the high‐voltage electrolytic charge storage capacitors used in conventional PFC pre‐regulators. In this paper, our previously proposed resonant current‐fed isolated PFC pre‐regulator is extended to operate in discontinuous conduction mode (DCM). It allows the use of the low‐voltage storage capacitors on the transformer secondary, and therefore extends the overall lifetime of the LED lighting system. A detailed procedure for finding the expected lifetime of the low‐voltage electrolytic capacitor is given. As before, the high‐voltage stress on the main switches, which is typical in current‐fed isolated converters, is reduced substantially by taking advantage of the transformer leakage inductance necessary for resonance. Additionally, high efficiency is ensured by the use of dual non‐cascading structures. Steady‐state state‐space averaging analysis is performed for designing the converter in DCM operation. A prototype converter is built to verify performance of the proposed PFC LED pre‐regulator. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Amir Bagheran 《电力部件与系统》2020,48(6-7):682-696
Abstract The high-brightness light-emitting diodes (LEDs) require an AC/DC converter with power factor correction (PFC). The large output electrolytic capacitor, which is used to minimize the low frequency LED current ripple, degrades the operating lifetime of the LED driver. In order to increase the lifetime of an AC–DC LED driver, the electrolytic capacitor should be eliminated without significantly increasing the output current ripple. In this article, an isolated single-stage single-switch AC/DC high power factor LED driver without electrolytic capacitor is proposed in which a zeta power factor (PF) corrector is integrated with a forward converter. The detailed theoretical analysis and design procedure of the proposed single-stage PFC converter is presented. The experimental results of a 110 Vrms, 21?W prototype verify the theoretical analysis. The input PF is 0.99 in the proposed converter that complies with lighting equipment standards such as IEC-1000-3-2 for class C equipment. 相似文献
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Hongbo Ma Jih‐Sheng Lai Quanyuan Feng Wensong Yu Cong Zheng 《International Journal of Circuit Theory and Applications》2013,41(5):514-534
The AC–DC power supply for LED lighting application requires a long lifetime while maintaining high‐efficiency, high power factor and low cost. However, a typical design uses electrolytic capacitor as storage capacitor, which is not only bulky but also with short life span, thus hampering performance improvement of the entire LED lighting system. In this article, a SEPIC‐derived power factor correction topology is proposed as the first stage for driving multiple lighting LED lamps. Along with a relatively large voltage ripple allowable in a two‐stage design, the proposal of LED lamp driver is able to eliminate the electrolytic capacitor while maintaining high power factor and high efficiency. To further increase the efficiency of LED driver, we introduced and used the twin‐bus buck converter as the second‐stage current regulator with Pulse Width Modulation (PWM) dimming function. The basic operating principle and the deign consideration are discussed in detail. A 50‐W prototype has been built and tested to verify the proposal. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Automatic current‐sharing extendable two‐channel LED driver with non‐pulsating input current and zero dc flux 下载免费PDF全文
K.I. Hwu W.Z. Jiang W.H. Chen 《International Journal of Circuit Theory and Applications》2018,46(8):1462-1484
A 2‐channel LED driver is presented herein, which possesses non‐pulsating input current and automatic current sharing. There are 4 features in the proposed LED driver. First, due to an input inductor, the input current is non‐pulsating, which makes the life of the renewable energy module or input capacitor longer. Second, each coupled inductor winding has a capacitor connected in series. Therefore, the dc magnetizing bias current is zero, and this can improve the iron core utilization, making the core loss and size reduced. Third, the number of LED channels can be extended by increasing windings. Fourth, the LED currents can be almost identical even if there are different LED numbers in LED strings. Eventually, the proposed LED driver is verified by simulation and experiment. 相似文献
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Dimmable integrated CMOS LED driver based on a resonant DC/DC hybrid‐switched capacitor converter 下载免费PDF全文
Juan C. Castellanos M. Turhan Marcel A.M. Hendrix Arthur van Roermund Eugenio Cantatore 《International Journal of Circuit Theory and Applications》2018,46(8):1485-1502
This paper presents a 7.7 ‐ mm2 on‐chip LED driver based on a DC/DC resonant hybrid‐switched capacitor converter operating in the MHz range with and without output capacitor. The converter operation allows continuously dimming the LED while keeping control on both peak and average current. Also, it features no flickering even in the absence of output capacitor and for light dimmed down to 10% of the nominal value. The capacitors and switches of the LED driver are integrated on a single IC die fabricated in a low‐cost 5 V 0.18‐μm bulk CMOS technology. This LED driver uses a small (0.7 mm2) inductor of 100 nH, which is 10 times smaller value than prior art integrated inductive LED drivers, still showing a competitive peak efficiency of 93% and achieving a power density of 0.26 W/mm2 (0.34 W/mm3). 相似文献
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《International Journal of Circuit Theory and Applications》2017,45(12):2290-2306
In this paper, a novel single‐switch DC–DC converter is proposed for dimmable MR16 light‐emitting diode (LED) drivers. The proposed driver can achieve very low output voltage ripple without using MHz switching frequency; therefore, small non‐electrolytic capacitors can be used to achieve longer lifetime and higher efficiency. Also, because of special merit of the proposed converter, it can be designed so that much wider duty ratio operating range can be achieved for LEDs. Hence, better digital dimming level resolution can be attained. Finally, a prototype driver for MR16 LED lamps is constructed to demonstrate the effectiveness of the converter. Experimental results show that a maximum efficiency of 92% can be achieved. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Modelling of battery‐powered boost DC–DC power LED driver with parasitics by multivariate power series expansion 下载免费PDF全文
Adam Rudziński 《International Journal of Circuit Theory and Applications》2015,43(9):1197-1208
This paper presents an analytic model of a battery‐powered boost DC–DC converter driving a power light emitting diode. The model is capable of taking into account parasitic components, including series resistances, parasitic capacitances and inductances. Unlike the standard approach to the converter modelling, the discussed model does not require any assumptions concerning current and voltage waveforms. It is based on power series expansion in normalized values of the parasitic components, leading to expressions comprising only physical parameters of the circuit. First‐order corrections are derived and illustrated in this paper. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Jing‐Yuan Lin Chao‐Fu Wang Chien‐Yu Lin John L Chen Jian‐Min Wang 《International Journal of Circuit Theory and Applications》2015,43(10):1351-1366
This paper proposes an active‐clamping flyback converter using an integrated transformer. The proposed converter is composed of two active‐clamp flyback converters. The presented converter can balance the total load current between secondary sides of two transformers so that the rectifier diode conduction loss is reduced. Also, the main switch of one converter is the auxiliary switch for the other converter, so that only two switches are required and both can achieve zero‐voltage‐switching operation. The two transformers are integrated into one magnetic core; therefore, the volume and copper loss of transformer can be reduced. Detailed analysis and design of this integrated magnetic active‐clamping flyback converter are described. Experimental results are recorded for a prototype converter with an AC input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 5 A, operating at a switching frequency of 100 kHz. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Toshihiko Tanaka Shigeyuki Funabiki Masafumi Nakazato 《Electrical Engineering in Japan》2005,151(1):66-75
This paper introduces a new approach to the capacitor‐commutated converters (CCCs) for HVDC systems. A small‐rated three‐phase voltage‐source PWM converter is connected between a series commutation capacitor and thyristor converter through matching transformers. The PWM converter acts as auxiliary commutation‐capacitor for the thyristor converter while the series passive capacitor acts as the main commutation capacitor. The capacitance, which is the sum of the small‐rated active and series passive capacitors, is variable, so that stable commutation is obtained. In CCCs, commutation failure occurs when the AC bus voltage is recovered whereas the proposed combined commutation‐capacitor can achieve successful commutation for both rapidly decreasing and increasing AC bus voltages. The basic principle of the proposed active–passive capacitor‐commutated converter is discussed in detail. Then, constant margin angle control with a constant firing angle of the thyristor converter is proposed using a function generator block. Digital simulation demonstrates the novelty and effectiveness of the proposed active–passive capacitor‐commutated converter. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(1): 66–75, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20030 相似文献
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Huang‐Jen Chiu Yu‐Kang Lo Shih‐Jen Cheng Yeong‐Chang Yan Hung‐Chi Lee Kuan‐Hung Wu Chung‐Yi Lin Shao‐Shih Ho Ming‐Hsiang Tseng Fu‐Hsien Huang 《International Journal of Circuit Theory and Applications》2011,39(11):1161-1175
In this paper, we study the feasibility of a single‐stage lighting LED lamp driver with low DC bus voltage. The operating principles and design considerations for the LED lamp driver in this study are analyzed and discussed in detail. A laboratory prototype has been built and tested. Using the prototype, high efficiency, high‐power factor and LED current control were achieved using a wide AC input voltage range from 90 to 270 V. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献