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.

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 Step-Up Series Resonant DC–DC Converter with Bidirectional-Switch-Based Boost Rectifier for Wide Input Voltage Range Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3747 ◽  
Author(s):  
Abualkasim Bakeer ◽  
Andrii Chub ◽  
Dmitri Vinnikov
Keyword(s):  
Theoretical Analysis ◽  
Duty Cycle ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Switching Frequency ◽  
Voltage Gain ◽  
Voltage Range ◽  
Dc Voltage ◽  
Wide Range ◽  
Series Resonant

This paper proposes a high gain DC–DC converter based on the series resonant converter (SRC) for photovoltaic (PV) applications. This study considers low power applications, where the resonant inductance is usually relatively small to reduce the cost of the converter realization, which results in low-quality factor values. On the other hand, these SRCs can be controlled at a fixed switching frequency. The proposed topology utilizes a bidirectional switch (AC switch) to regulate the input voltage in a wide range. This study shows that the existing topology with a bidirectional switch has a limited input voltage regulation range. To avoid this issue, the resonant tank is rearranged in the proposed converter to the resonance capacitor before the bidirectional switch. By this rearrangement, the dependence of the DC voltage gain on the duty cycle is changed, so the proposed converter requires a smaller duty cycle than that of the existing counterpart at the same gain. Theoretical analysis shows that the input voltage regulation range is extended to the region of high DC voltage gain values at the maximum input current. Contrary to the existing counterpart, the proposed converter can be realized with a wide range of the resonant inductance values without compromising the input voltage regulation range. Nevertheless, the proposed converter maintains advantages of the SRC, such as zero voltage switching (ZVS) turn-on of the primary-side semiconductor switches. In addition, the output-side diodes are turned off at zero current. The proposed converter is analyzed and compared with the existing counterpart theoretically and experimentally. A 300 W experimental prototype is used to validate the theoretical analysis of the proposed converter. The peak efficiency of the converter is 96.5%.

scholarly journals Desain dan Simulasi Dual Input Single Output Buck Converter dengan Kontrol Fuzzy

2021 ◽  
Vol 10 (1) ◽  
pp. 63-70
Author(s):  
Abdul Rahman Wachid ◽  
Endro Wahjono ◽  
Syechu Dwitya Nugraha Nugraha
Keyword(s):  
Duty Cycle ◽  
Buck Converter ◽  
Set Point ◽  
Single Output

Dalam makalah ini didesain dan disimulasikan dual input single output buck converter dengan kontrol fuzzy untuk suplai beban DC dengan menggunakan software PSIM. Dual input single output converter dapat bekerja dengan dua sumber yang berbeda. Penggunaan dua sumber dari panel surya dan turbin angin adalah cara alternatif untuk mendapatkan nilai daya output yang lebih besar untuk suplai beban DC. Sumber dari panel surya dan turbin angin akan masuk ke dalam sistem rangkaian dual input buck converter secara bersamaan dengan kondisi sumber terpasang secara seri. Agar kedua sumber dapat bekerja secara bersamaan, duty cycle diatur menggunakan kontrol fuzzy sehingga tegangan output sesuai dengan yang diinginkan. Simulasi dilakukan dengan kondisi panel surya yang memiliki nilai iradiasi dan temperatur berubah-ubah serta turbin angin yang juga terkena angin dengan kecepatan tidak tetap, yaitu antara 4-8 m/s. Hasil simulasi menunjukkan bahwa dual input single output buck converter dapat bekerja dalam keadaan disuplai oleh dua sumber yang berbeda dengan tegangan output converter yang stabil di set point, yaitu 14,4 volt.

scholarly journals Proof-of-Concept Simulasi Kadar Saturasi Oksigen untuk Evaluasi Pulse Oximeter

2018 ◽  
Vol 6 (1) ◽  
pp. 110
Author(s):  
FUAD UGHI
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximeter ◽  
Light Emitting Diode ◽  
System Level ◽  
Proof Of Concept ◽  
Led Driver ◽  
Digital To Analog Converter ◽  
Light Emitting ◽  
Analog Converter ◽  
Digital To Analog

ABSTRAKSimulator SpO2 yang mengemulasikan sinyal yang ekuivalen dengan saturasi oksigen pada manusia, dapat digunakan untuk evaluasi repeatibility pulse oximeter. Simulator ini tersedia di pasaran dengan harga yang cukup mahal di Indonesia, di kisaran 80-100 juta rupiah. Studi ini bertujuan untuk mengembangkan simulator SpO2 dengan biaya rendah, menggunakan komponen elektronika umum yang ada di pasaran. Karakteristik simulasi mengacu kepada referensi yang diambil dari simulator komersial dengan menggunakan sistem akuisisi data berbasis LabVIEW. Kadar saturasi oksigen disimulasikan dengan mengatur intensitas cahaya light emitting diode (LED), untuk meniru penyerapan cahaya oleh darah pada pembuluh arteri. Digital to analog converter digunakan sebagai LED driver, untuk mengatur besar tegangan ke LED yang berbanding lurus dengan intensitas cahaya. Sebagai pembuktian konsep, studi ini berhasil menyimulasikan kadar saturasi oksigen 80% dengan galat mencapai 11.25%, dan 80 denyut jantung per menit dengan galat 6.25%. Hasil simulasi belum bisa dibandingkan dengan simulator komersial, karena hasil yang belum stabil. Total biaya untuk komponen perangkat keras, mencapai satu juta rupiah.Kata kunci: simulator, saturasi oksigen, pulse oximeter, digital to analog converter, light emitting diode ABSTRACTSpO2 simulator, which emulates signal that equivalent to oxygen saturation level of human, can be used to evaluate repeatibility of pulse oximeter. SpO2 simulators are available in Indonesia, but the price is quite expensive, in range of 80-100 million rupiah. The study aims to develop low-cost SpO2 simulator, using common electronic components. Characteristic of simulation refer to reference data, which taken from commercial simulator using LabVIEW based data acquisition system. Level of oxygen saturation is simulated by adjusting beam intensity of light emitting diode (LED), to imitate light absorbance by arterial blood. Digital to analog converter is used as LED driver, to control voltage to LED that directly proportional to light intensity. As a proof of concept, SpO2 simulation has been successfully performed at level 80% with error reaches 11.25% deviation, and heart rate 80 beat per minute with error reaches 6.25%. The simulation result had not compared yet to a commercial simulator, due to the unstable result. Total cost for hardware components of the prototype is around one million rupiah.Keywords: simulator, oxygen saturation, pulse oximeter, digital to analog converter, light emitting diode

scholarly journals A High-Input Voltage Two-Phase Series-Capacitor DC-DC Buck Converter

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Salahaldein Ahmed Rmila ◽  
Simon S. Ang
Keyword(s):  
Input Voltage ◽  
Buck Converter ◽  
External Control ◽  
Storage Capacitor ◽  
High Input ◽  
Two Phase ◽  
Current Sensing ◽  
Current Sharing ◽  
Capacitor Voltage ◽  
Series Capacitor

A high-input voltage 2-phase series-capacitor (2-pscB) DC-DC buck converter is theoretically analyzed, designed, and implemented. A new design approach for an automatic current sharing scheme was presented for a 2-phase series-capacitor synchronous buck converter. The series-capacitor voltage is used to achieve current sharing between phases without a current sensing circuit or external control loop as each phase inductor charges and discharges the series capacitor to maintain its average capacitor voltage constant. A novel isolated gate driver circuit to accommodate an energy storage capacitor is proposed to deliver isolated gate voltages to the switching transistors. An I2 control scheme that uses only one feedback path control for the four gate drivers is proposed to enable higher voltage conversion. An experimental 110-12 V 6 A load prototype converter was designed, and its current sharing characteristics were experimentally verified.

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