A new active Hybrid-Series-Parallel PWM dimming scheme for off-line integrated LED drivers with high efficiency and fast dynamics

In this paper, a class E type high frequency DC/DC converter is proposed. The detailed analysis and parameter optimal design method are depicted in this paper. Based on optimal parameters, the switch can operate in ZVS condition. Also, to reduce the driving losses, a multistage resonant driving circuit is adopted and analyzed in this paper, which can utilize the energy stored in the switch input capacitance. The ON/OFF control method is adopted to regulate output voltage and the enable signal frequency is 340kHz. From the output side, the circuit can be seen as operating at enable signal frequency with high sampling frequency. A 20MHz prototype is built in this paper, which verifies the feasibility of high frequency converter and control method.

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“…is the resonant frequency of resonant inductor and capacitor. To achieve ZVS of switch, the equation (11) and (12) should be satisfied.…”

Section: ( )mentioning

confidence: 99%

“…Secondly in terms of control method, due to the low operating frequency of conventional converter, the output voltage can be regulated by pulse width modulation (PWM) [10,11]. Another method is the pulse frequency modulation (PFM) [12,13].…”

Section: Introductionmentioning

confidence: 99%

Analysis and Design of a Class E Type High Frequency DC–DC Converter Based on Resonant Driving Circuit

Guan

Yao

Wang

et al. 2020

IEEE Open J. Ind. Electron. Soc.

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“…Thus, the values of the inductances are chosen in order to minimise the bulk voltage, for higher PF and lower total harmonic distortion. Following this two constrains and applying them in (11) and 12, the calculated input-buck inductance is 420 μH, and the calculated magnetising inductance is 315 μH, as shown in Table 1.…”

Section: Design Of the Convertermentioning

confidence: 99%

“…7 shows that the estimated value is acceptable, because when using a value higher than this one, up to 1.5 times, an enhancement of only 1% is reached, and below this value, a serious decay in the performance occurs. Table 1 illustrates the drive parameters, used in (11) and (12), so Fig. 8 is performed.…”

Section: Design Of the Convertermentioning

confidence: 99%

“…Besides, their higher efficacy compared to other sources of lighting reaches 250 lm/W [7,8]. More features such as smaller size, faster response, robustness, reliability, and colour rendering index are also shown by the LEDs [9][10][11][12][13][14]. A drawback shown by the LEDs is that they cannot be connected directly to the mains due to their low internal impedance.…”

Section: Introductionmentioning

confidence: 99%

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Analysis, design, and experimentation of the active hybrid‐series‐parallel PWM dimming scheme for high‐efficient off‐line LED drivers

Abdelmessih

Alonso

Costa

2019

IET Power Electronics

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This study presents a high power factor (PF) light-emitting diode (LED) driver featuring a pulse width modulation (PWM) dimming technique. The integrated buck-flyback-buck converter (IBFBC) is built by connecting a buck converter to the integrated buck-flyback converter's output. The IBFBC ensures a constant output current regulation as well as high PF at all dimming ratios. The purpose of the output buck converter is to clear up the discontinuous power operation created by the PWM dimming. This occurs when the buck converter absorbs the output power, at LED switched-off, and sends it back to the input. Thus, the IBFBC maintains the operational enhancement shown by the hybrid-series-parallel (HSP)-PWM technique, ensuring greater efficiency. This study explains the operating principles of the IBFBC using circuit diagrams as well as an average model for the entire converter. Moreover, the study presents a mathematical analysis of the IBFBC power flow. It provides guidance on how to select the optimum value for the output buck inductance. A 230 V, 50 Hz input, 160 V output, 100 W AC-DC converter operating at 100 kHz has been implemented. The prototype is fully tested to demonstrate the active HSP-PWM technique. An efficiency ranging 50-86% corresponding to the dimming ratio of 5-100% is reached, where 5% dimming refers to an output power of 4 W.

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A high-power PCCM LED driver based on GaN eHEMT with hybrid dimming modes

Lin

Zhang

et al. 2021

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Purpose The purpose of this study is to design a more flexible and larger range of the dimming circuit that achieves the independence of multiple LED strings drive and can time-multiplex the power circuit. Design/methodology/approach The state-space method is used to model the BUCK circuit working in Pseudo continuous conduction mode, analyze the frequency characteristics of the system transfer function and design the compensation network. Build a simulation platform on the Orcad PSPICE platform and verify the function of the designed circuit through the simulation results. Use Altium Designer 16 to draw the printed circuit board, complete the welding of various components and use the oscilloscope, direct current (DC) power supply and a signal generator to verify the circuit function. Findings A prototype of the proposed LED driver is fabricated and tested. The measurement results show that the switching frequency can be increased to 1 MHz, Power inductance is 2.2 µH, which is smaller than current research. The dimming ratio can be set from 10% to 100%. The proposed LED driver can output more than 48 W and achieve a peak conversion efficiency of 91%. Originality/value The proposed LED driver adopts pulse width modulation (PWM) dimming at a lower dimming ratio and adopts DC dimming at a larger dimming ratio to realize switching PWM dimming to analog dimming. The control strategy can be more precise and have a wide range of dimming.

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A new active Hybrid-Series-Parallel PWM dimming scheme for off-line integrated LED drivers with high efficiency and fast dynamics

Cited by 15 publications

References 17 publications

Analysis and Design of a Class E Type High Frequency DC–DC Converter Based on Resonant Driving Circuit

Analysis and Design of a Class E Type High Frequency DC–DC Converter Based on Resonant Driving Circuit

Analysis, design, and experimentation of the active hybrid‐series‐parallel PWM dimming scheme for high‐efficient off‐line LED drivers

A high-power PCCM LED driver based on GaN eHEMT with hybrid dimming modes

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