Electrolytic Capacitorless AC/DC LED Driver

2019 ◽  
Vol 28 (12) ◽  
pp. 1950200
Author(s):  
Changyuan Chang ◽  
Xiong Han ◽  
Menglin Wu ◽  
Dadi Zhao ◽  
Hongliang Xu
Keyword(s):  
Input Voltage ◽  
Buck Converter ◽  
Electrolytic Capacitor ◽  
Conduction Time ◽  
Test Results ◽  
Led Driver ◽  
Power Difference ◽  
Load Regulation ◽  
Constant Output ◽  
Conduction Mode

This paper presents electrolytic capacitorless AC/DC LED driver. It adopts Boost–Buck topology, through modulation of the conduction time [Formula: see text] and the change of input current reference, to reduce the instantaneous input and output power difference, so a smaller film capacitor can be used instead of the electrolytic capacitor. Therefore, LED driver power life has been effectively improved. The Buck converter operates in the inductor current discontinuous conduction mode to achieve constant output current by controlling the peak current. The control IC is fabricated in TSMC 0.35-[Formula: see text]m 5-V/650-V CMOS/LDMOS process, and verified in a 72-V/150-mA circuit prototype. The test results show that when the range of input voltage is 175–264 Vac, the efficiency of the system is 83%, the voltage linear regulation is [Formula: see text]%, the load regulation is [Formula: see text]%, and the electrolytic capacitor is replaced by 470-nF CBB capacitor under the condition that the power factor is above 0.7. Therefore, the design of the control chip in the LED driver has a very good application prospect.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

COMPLEX DYNAMICS AND FAST-SLOW SCALE INSTABILITY IN CURRENT-MODE CONTROLLED BUCK CONVERTER WITH CONSTANT CURRENT LOAD

2013 ◽  
Vol 23 (04) ◽  
pp. 1350062 ◽  
Author(s):  
GUOHUA ZHOU ◽  
BOCHENG BAO ◽  
JIANPING XU
Keyword(s):  
Complex Dynamics ◽  
Period Doubling ◽  
Current Mode ◽  
Input Voltage ◽  
Second Order ◽  
Buck Converter ◽  
Constant Current ◽  
Current Load ◽  
Time Model ◽  
Conduction Mode

The complex dynamics and coexisting fast-slow scale instability in current-mode controlled buck converter with constant current load (CCL), operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), are investigated in this paper. Via cycle-by-cycle computer simulation and experimental measurement of current-mode controlled buck converter with CCL, it is found that a unique fast-slow scale instability exists in the second-order switching converter. It is also found that a unique period-doubling accompanied by Neimark–Sacker bifurcation exists in this simple second-order converter, which is different from period-doubling or Neimark–Sacker bifurcations reported previously. Based on a nonlinear discrete-time model and the corresponding Jacobian, the effects of CCL and input voltage on the dynamics of current-mode controlled buck converter are investigated and verified theoretically. Fixed point analysis for slow-scale low-frequency oscillation is also given to verify the dynamics and the coexisting fast-slow scale instability.

scholarly journals ESR Estimation Schemes of Output Capacitor for Buck Converter from Capacitor Perspective

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1596
Author(s):  
Lei Ren ◽  
Lei Zhang ◽  
Chunying Gong
Keyword(s):  
Buck Converter ◽  
Electrolytic Capacitor ◽  
Equivalent Series Resistance ◽  
Power Electronic Converters ◽  
Aluminum Electrolytic Capacitor ◽  
Advantages And Disadvantages ◽  
Optimal Period ◽  
Current Characteristics ◽  
Output Capacitor ◽  
Conduction Mode

The aluminum electrolytic capacitor (AEC) is one of the most vulnerable parts in power electronic converters and its reliability is crucial to the whole system. With the growth of service time, the equivalent series resistance (ESR) increases and the capacitance (C) decreases due to the loss of electrolytes, which will result in extra power loss and even damage to transistors. To prevent significant damages, the AEC must be replaced at an optimal period and online health monitoring is indispensable. Through the analysis of degradation parameters (ESR and C), ESR is proved to be a better health indicator and therefore is determined as the monitoring parameter for AEC. From the capacitor perspective, ESR estimation schemes of output capacitors for a Buck converter are studied. Based on the voltage–current characteristics, two ESR calculation models are proposed, which are applicable for both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). From the point of implementation view, the advantages and disadvantages of the two estimation schemes are pointed out, respectively. A Buck prototype is built and tested, and simulation and experimental results are provided to validate the proposed ESR estimation schemes.

scholarly journals Dynamic analysis of the input-controlled buck converter fed by a photovoltaic array

2008 ◽  
Vol 19 (4) ◽  
pp. 463-474 ◽  
Author(s):  
Marcelo Gradella Villalva ◽  
Ernesto Ruppert Filho
Keyword(s):  
Dynamic Analysis ◽  
Output Voltage ◽  
Input Voltage ◽  
Buck Converter ◽  
Special Situation ◽  
Photovoltaic Array ◽  
Photovoltaic Applications ◽  
Constant Output

The control of the input voltage of DC-DC converters is frequently required in photovoltaic applications. In this special situation, unlike conventional converters, the output voltage is constant and the input voltage is controlled. This paper deals with the analysis and the control of the buck converter with constant output voltage and variable input.

scholarly journals Analysis and Control of Electrolytic Capacitor-Less LED Driver Based on Harmonic Injection Technique

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3030 ◽  
Author(s):  
Mahmoud Nassary ◽  
Mohamed Orabi ◽  
Manuel Arias ◽  
Emad Ahmed ◽  
El-Sayed Hasaneen
Keyword(s):  
Power Factor ◽  
Low Frequency ◽  
Buck Converter ◽  
Electrolytic Capacitor ◽  
Injection Technique ◽  
Led Driver ◽  
Harmonic Injection ◽  
Output Capacitor ◽  
And Control ◽  
Led Drivers

AC-DC LED drivers may have a lifespan shorter than the lifespan of LED chips if electrolytic capacitors are used in their construction. Using film capacitors solves this problem but, as their capacitance is considerably lower, the low-frequency ripple will increase. Solving this problem by limiting the output ripple to safe values is possible by distorting the input current using harmonic injection technique, as long as these harmonics still complies with Power Factor Regulations (Energy Star). This harmonic injection alleviates the requirements imposed to the output capacitor in order to limit the low-frequency ripple in the output. This idea is based on the fact that LEDs can be driven by pulsating current with a limited Peak-To-Average Ratio (PTAR) without affecting their performance. By considering the accurate model of LEDs, instead of the typical equivalent resistance, this paper presents an improved and more reliable calculation of the intended harmonic injection. Wherein, its orders and values can be determined for each input/output voltage to obtain the specified PTAR and Power Factor (PF). Also, this harmonic injection can be simply implemented using a single feedback loop, its control circuit has features of wide bandwidth, simple, single-loop and lower cost. A 21W AC-DC buck converter is built to validate the proposed circuit and the derived mathematical model and it complies with IEC61000 3-2 class D standard.

scholarly journals Parametric Analysis of Automotive Grade Buck Converters

2021 ◽  
Vol 23 (06) ◽  
pp. 395-401
Author(s):  
Vajra R Singh ◽  
◽  
Sindhu Rajendran ◽  
Keyword(s):  
Power Systems ◽  
Parametric Analysis ◽  
Input Voltage ◽  
Buck Converter ◽  
Buck Converters ◽  
Output Current ◽  
System A ◽  
Constant Output ◽  
Design Characteristics ◽  
Lower Voltage

The current power system design in electric automobiles has become increasingly complicated due to innumerable electronics which are required to be integrated for the effective functioning of the system. A DC/DC buck converter is primarily used in order to control and regulate the working of peripheral systems in an automotive, the voltage from the battery is stepped down in order to power systems like the USB ports and the dashboard interfaces. There are multiple regulators available but in order to assess the feasibility of the available IC’s to the interface, the design characteristics and specifications require stepping down the input voltage from a higher voltage to produce a requirement specific lower voltage and constant output current in amperes. A comprehensive parametric analysis of LM23625 and LM23630 is performed by simulating buck regulators operating at respective switching frequencies.

scholarly journals Bridgeless Buck-Boost PFC Rectifier with Positive Output Voltage

2019 ◽  
Vol 9 (17) ◽  
pp. 3483 ◽  
Author(s):  
Kuo-Ing Hwu ◽  
Yu-Kun Tai ◽  
Yu-Ping He
Keyword(s):  
Power Factor ◽  
Output Voltage ◽  
Power Factor Correction ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Experimental Results ◽  
Control Force ◽  
Led Driver ◽  
Voltage Follower ◽  
Conduction Mode

A bridgeless buck-boost power-factor-correction (PFC) rectifier with positive output voltage is proposed herein. This PFC rectifier operates in the discontinuous conduction mode (DCM). Owing to the DCM, a good performance on PF is easily achieved as well as no reverse recovery currents being generated from the diodes. By means of output voltage sensing along with the traditional voltage-follower control, a proper control force is created to drive the switches. By doing so, not only the output voltage is stably controlled at a given value, but also the input current tracks the input voltage as tightly as possible. In addition, the accompanying harmonic distortion meets the requirements of the IEC6100-3-2 Class C harmonics standard, and accordingly, the proposed rectifier is suitable for the AC-DC LED driver. Finally, via mathematical deductions and experimental results, the effectiveness of the proposed bridgeless buck-boost PFC rectifier is verified.

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