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Summary: 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. [ABSTRACT FROM AUTHOR]

Summary: In this study, an extensible 2‐phase interleaved high step‐up converter with automatic current balance is presented. This converter uses coupled inductors and energy‐transferring capacitors to improve the voltage gain of the traditional 2‐phase interleaved boost converter as well as employs these energy transferring capacitors to do automatic current balance. Furthermore, the voltage gain can be enhanced not only by adjusting the turns ratio but also by increasing the numbers of phases, diodes, and energy‐transferring capacitors. Therefore, it can be used in high input current and high step‐up voltage applications. In this paper, the basic operating principles of the proposed converter are described and analyzed, and finally, its effectiveness is demonstrated by experiment. In addition, the field‐programmable gate array, named EP13T100C8N and manufactured by Altera Co, is used as a control kernel, and an experimental prototype, with input voltage of 12 V, output voltage of 200 V, and rated output power of 200 W, is given to provide the effectiveness of the proposed converter. [ABSTRACT FROM AUTHOR]

In this paper, a nonisolated two-phase interleaved LED driver with capacitive current sharing is presented. In the proposed LED driver, the current sharing capacitor can be used to balance the input inductor currents and the LED currents. Furthermore, only one grounded LED string current is sensed and controlled. Moreover, under the interleaved control, the input current ripple can be reduced. Finally, the operating principles, analyses, and experimental results are provided to verify the effectiveness of the proposed LED driver. [ABSTRACT FROM PUBLISHER]

In the high step-down voltage applications, the dc–dc converter with a high step-down voltage conversion ratio is usually used. Recently, a high step-down converter, named ultrahigh step-down converter, has been presented. As compared with the nonisolated tapped-inductor buck converter, the ultrahigh step-down converter has not only a higher voltage step-down gain but also a lower voltage spike. On the other hand, in the high-current applications, a multiple phase structure is preferable. Therefore, in this paper, a novel expandable two-phase interleaved ultrahigh step-down converter with automatic current balance is presented, which is derived from the existing single-phase ultrahigh step-down converter. There are four main advantages of the proposed converter. First, the step-down voltage gain is improved. Therefore, the turns ratio of each phase can be decreased. Second, due to the charge balance of the energy-transferring capacitor, the proposed two-phase ultrahigh step-down converter possesses an automatic current balance. Third, as compared with a single-phase ultrahigh step-down converter, the output current ripple can be reduced. Fourth, the phase number of the proposed converter can be expanded. Finally, the basic operating principle of the proposed converter is analyzed, and a prototype is constructed to verify its effectiveness by some experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, a single-switch coupled-inductor-based two-channel light-emitting diode (LED) driver with a passive regenerative snubber is presented. In the proposed LED driver, the energy-transferring capacitor is not only used to step up the voltage gain but also to achieve the current balance among LED strings. Moreover, a passive regenerative snubber is added not only to recycle the leakage inductance energy but also to improve the voltage gain. As compared with the prior work, only one switch is required. Thus, the configuration of the proposed LED driver is simpler. Since the proposed LED driver has a higher voltage gain than the prior work, the turns ratio of the proposed LED driver can be lower. Thus, the magnetic core size can be reduced. In addition, both LED drivers have the same component count. Finally, the operating principle, analysis, and experimental results are provided to verify the effectiveness of the proposed LED driver. [ABSTRACT FROM AUTHOR]

As generally acknowledged, the high step-up dc-dc converter is widely used in the sustainable energy system as the front-end stage of the dc-ac converter. Therefore, a high step-up converter combining one coupling inductor and two bootstrap capacitors, together with the active voltage-clamping circuit which pumps portion of the leakage inductance energy to the output, is presented herein. By doing so, the efficiency at light load can be upgraded greatly, and hence tends to be flat between the minimum load and the rated load. In this letter, the basic operating principles of this converter are first illustrated in detail, and second some experimental results are provided to demonstrate the effectiveness of the proposed high step-up converter topology. [ABSTRACT FROM AUTHOR]

In this paper, a novel voltage-boosting converter is presented, which combines one charge pump and one coupled inductor with the turns ratio. The corresponding voltage gain is greater than that of the existing step-up converter combining KY and buck-boost converters. Since the proposed converter possesses an output inductor, the output current is nonpulsating. After some mathematical deductions, an experimental setup with 12-V input voltage, 72-V output voltage, and 60-W output power is used to verify the effectiveness of the proposed converter. [ABSTRACT FROM PUBLISHER]

In this paper, novel high voltage-boosting converters are presented. By changing the connection position of the anode of the diode and by using different pulse-width-modulation control strategies, different voltage conversion ratios can be obtained. These converters are constructed based on bootstrap capacitors and boost inductors. Above all, two boost inductors with different values, connected in series, can still make the proposed converters work appropriately. Furthermore, although there are three switches in each converter, only one half-bridge gate driver and one low-side gate driver are needed, but no isolated gate driver would be needed. After some mathematical deductions, some experimental results are provided to verify the effectiveness of the proposed converters. [ABSTRACT FROM PUBLISHER]

A simple current-sharing control technique for the switching power supply is presented herein, which is based on the concept of the differential-mode transformer and which makes the load current evenly shared well among phases all over the line voltage and load current ranges. This current-sharing structure is very simple, and it makes the efficiency relatively high at light load, which is quite suitable for industrial applications with standby power considered. In this circuit, a synchronously rectified switch is used to further upgrade the efficiency, and the coupling output inductors in copolarity are utilized to decrease the phase current ripples. In this paper, the detailed basic operating principles, together with mathematical deductions, are first described, and second, some simulated and experimental results are provided to demonstrate the proposed control strategy. [ABSTRACT FROM AUTHOR]

In this letter, a KY boost converter is presented, which is the KY converter combined with the traditional synchronously rectified (SR) boost converter. Such a converter has continuous input and output inductor currents, different from the traditional SR boost converter, and has a larger voltage conversion ratio than the traditional SR boost converter does, and hence, this converter is very suitable for low-ripple applications. A detailed description of the proposed converter is presented herein along with a mathematical deduction and some experimental results. [ABSTRACT FROM PUBLISHER]

To overcome the traditional buck converter, which is difficult to achieve a high step-down gain with an appropriate duty cycle, a coupled-inductor-based step-down converter, named ultrahigh step-down converter, is proposed by Hwu et al. [11]. As compared with the buck converter, the ultrahigh step-down converter can achieve a much higher step-down gain, which can be determined by not only the duty cycle but also the turns ratio of the coupled inductor. However, the ultrahigh step-down converter is designed at a fixed input voltage of 48 V. In the telecommunication applications, the high dc bus voltage varies in a wide range, not kept at a fixed nominal voltage of 48 V. The experimental results show that as the input voltage increases, the efficiency of the ultrahigh step-down converter decreases. Therefore, in this paper, an improved ultrahigh step-down converter with a wide input voltage range is presented. According to the topology exchange, the voltage gain can be changed to a suitable one when the input voltage changes. By doing so, as compared with the ultrahigh step-down converter [11], the duty cycle of the proposed converter can be extended, and hence the efficiencies of the proposed converter can be improved. The proposed converter is verified by a wide input voltage (18–54 V), with an output voltage of 1.2 V and a rated output current of 10 A. [ABSTRACT FROM AUTHOR]