scholarly journals LLC LED Driver with Current-Sharing Capacitor Having Low Voltage Stress

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 112
Author(s):  
Wen-Zhuang Jiang ◽  
Kuo-Ing Hwu ◽  
Jenn-Jong Shieh
Keyword(s):  
Low Voltage ◽  
Light Emitting Diode ◽  
Input Voltage ◽  
Current Control ◽  
Constant Current ◽  
Resistive Load ◽  
Led Driver ◽  
Current Sharing ◽  
Voltage Stress ◽  
The Difference

In this paper, an LLC light-emitting diode (LLC LED) driver based on the current-sharing capacitor is presented. In the proposed LED driver, the LLC resonant converter is used to step down the high input voltage, to provide galvanic isolation, to offer a constant current for LEDs. Moreover, the current-sharing capacitor connected to the central-tapped point of the secondary-side winding is used to balance the currents in two LED strings. By doing so, the voltage stress on this capacitor is quite low. Above all, the equivalent forward voltages of the two LED strings are generally influenced by the temperature and the LED current, and this does not affect the current-sharing performance, as will be demonstrated by experiment on the difference in number of LEDs between the two LED strings. In addition, only the current in one LED string is sensed and controlled by negative feedback control, while the current in the other LED string is determined by the current-sharing capacitor. Moreover, this makes the current control so easy. Afterwards, the basic operating principles and analyses are given, particularly for how to derive the effective resistive load from the LED string. Eventually, some experimental results are provided to validate the effectiveness of the proposed LED driver.

scholarly journals Implementation of a Dimmable LED Driver with Extendable Parallel Structure and Capacitive Current Sharing

2019 ◽  
Vol 9 (23) ◽  
pp. 5177 ◽  
Author(s):  
Hwu ◽  
Tai ◽  
Tu
Keyword(s):  
Output Voltage ◽  
Current Control ◽  
Parallel Structure ◽  
Current Sensor ◽  
Led Driver ◽  
Capacitive Current ◽  
Current Sharing ◽  
Voltage Stress ◽  
Basic Operating ◽  
Field Programmable

A dimmable LED driver along with an extendable series structure and interleaved capacitive current sharing is presented herein, the LED connection of which is changed from the traditional series structure to the proposed parallel structure. The number of LED strings can be extended. As the number of LED strings is increased, the output voltage of this LED driver and the voltage stress on the main switch are ideally not influenced. Moreover, only one current sensor is needed to achieve current control and dimming. In this paper, the basic operating principle of the proposed LED driver is described and analyzed. Finally, the effectiveness of this LED driver is demonstrated by experiment based on the field-programmable gate array (FPGA).

scholarly journals High Voltage, Low Current High-Power Multichannel LEDs LLC Driver by Stacking Single-Ended Rectifiers with Balancing Capacitors

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 529
Author(s):  
Kang Hyun Yi
Keyword(s):  
High Voltage ◽  
High Power ◽  
Low Voltage ◽  
Driving Voltage ◽  
Led Driver ◽  
Leakage Inductance ◽  
Voltage Stress ◽  
Driver Circuit ◽  
In Series ◽  
The Difference

In this paper, a new LLC converter for series-connected, high-voltage LEDs is proposed. The proposed LLC converter consists of two stacked, single-ended rectifiers and one balancing capacitor, to compensate for the current deviation of two individual LED strings. The proposed LLC LED driver can use a diode with low voltage stress, even if the secondary LED is connected in series to have a high driving voltage. In addition, even if several series-connected LEDs are changed into two-stacked structures, the balancing capacitor can compensate for the current deviation of the two separated LEDs, as well as the difference in leakage inductance of the two stacked single-ended rectifiers. The balancing capacitor can be made equal to the voltage tolerance of the stacked, single-ended rectifier diodes. The proposed circuit can be easily extended to a series channel LED driver circuit, without increasing the voltage stress. To verify the characteristics and operation of the proposed LLC LED driver, a 260W high-power LED driver is implemented.

scholarly journals Development of Four-Channel Buck-Type LED Driver with Automatic Current Sharing

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7844
Author(s):  
Yeu-Torng Yau ◽  
Kuo-Ing Hwu ◽  
Yao-De Tsai
Keyword(s):  
Duty Cycle ◽  
Light Emitting Diode ◽  
Input Voltage ◽  
Buck Converter ◽  
Led Driver ◽  
Voltage Range ◽  
Light Emitting ◽  
Single Output ◽  
Current Sharing ◽  
Single Input

A buck-type light-emitting diode (LED) driver is proposed herein. The proposed LED driver automatically possesses current sharing and high step-down voltage gain. Without complex control, the proposed LED driver, with a single input and multiple outputs, can achieve automatic current sharing of four-channel LED strings, even under the different number of LEDs of each LED string. Furthermore, as compared with the traditional four-phase interleaved buck converter with a single input and a single output having current sharing required, the proposed circuit has the duty cycle up to 0.5, not 0.25, meaning that under the same input voltage the latter has a wider output voltage range than that of the former. Above all, if the proposed circuit with N outputs, then it still has the duty cycle up to 0.5, not one over N as shown traditionally. Moreover, as compared with the current sharing based on the differential-mode transformer, the proposed circuit has no magnetic resetting loop required. In this paper, the operating principles and design considerations of the proposed converter are discussed. Finally, the theoretical analyses and performances of the proposed LED driver are verified by simulation and experiment.

Implementation of Single-Phase Two-Switch Midpoint Unidirectional Multilevel Converter System

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Open Loop ◽  
Current Control ◽  
Control Technique ◽  
Control Scheme

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.

A Single-Stage LED Driver Based on Flyback and Modified Class-E Resonant Converters With Low-Voltage Stress

2019 ◽  
Vol 66 (11) ◽  
pp. 8463-8473 ◽  
Author(s):  
Yijie Wang ◽  
Fang Li ◽  
Yuping Qiu ◽  
Shanshan Gao ◽  
Yueshi Guan ◽  
...  
Keyword(s):  
Low Voltage ◽  
Single Stage ◽  
Resonant Converters ◽  
Led Driver ◽  
Voltage Stress ◽  
Class E

scholarly journals Decentralized Control Method of ISOP Converter for Input Voltage Sharing and Output Current Sharing in Current Control Loop

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1114
Author(s):  
Sung-Hun Kim ◽  
Bum-Jun Kim ◽  
Jung-Min Park ◽  
Chung-Yuen Won
Keyword(s):  
Decentralized Control ◽  
Control Method ◽  
Input Voltage ◽  
Current Control ◽  
Control Loop ◽  
Output Current ◽  
Signal Model ◽  
Control Loops ◽  
Current Sharing ◽  
Small Signal Model

Input-Series-Output-Parallel (ISOP) converters, a kind of modular converter, are used in high-input voltage and high-output current applications. In ISOP converters, Input Voltage Sharing (IVS) and Output Current Sharing (OCS) should be implemented for stable operation. In order to solve this problem, this paper proposes a decentralized control method. In the proposed control, output current reference is changed according to the decentralized control characteristic in individual current control loops. In this way, the proposed control method is able to implement IVS and OCS without communication. Also, this method can be easily used in current control loops and has high reliability compared to conventional control methods that require communication. In this paper, the operation principle is described to elucidate the proposed control and a small signal model of an ISOP converter is also implemented. Based on the small signal model, IVS stability analysis is performed using pole-zero maps with varying coefficients and control gains. In addition, the current control loop is designed in a stable region. In order to demonstrate the proposed control method, a prototype ISOP converter is configured using full-bridge converters. The performance of IVS and OCS in an ISOP converter is verified by experimental result.

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