High-Precision Digital Constant Current Controller with Demagnetization-Time Compensation for Primary-Side Regulation Flyback Converter

2016 ◽  
Vol 25 (08) ◽  
pp. 1650095 ◽  
Author(s):  
Changyuan Chang ◽  
Xiaomin Huang ◽  
Yuanye Li ◽  
Yao Chen
Keyword(s):  
Constant Current ◽  
Output Current ◽  
Side Peak ◽  
Load Range ◽  
Current Output ◽  
Flyback Converter ◽  
Current Controller ◽  
Wide Range ◽  
Hardware Description ◽  
Constant Output

A novel digital constant output current controller with demagnetization-time compensation for flyback converter is proposed in this paper. The secondary winding demagnetization time [Formula: see text] is sampled from the comparison module output signal by output voltage sampling state machine. The ratio between [Formula: see text] and switching period [Formula: see text] is kept constant by bidirectional counter module to achieve constant output current based on invariable primary-side peak-current. Meanwhile, demagnetization-time compensation is proposed in order to enhance load regulation ratio. The compensation [Formula: see text] acquired from a look-up table, is utilized to compensate the impacts caused by the delay [Formula: see text] from the process of sampling the signal of [Formula: see text]. The digital controller (DC) is implemented by hardware description language Verilog HDL. Experimental results of the proposed 2A constant current output flyback converter based on FPGA(EP2C8Q208C8N) indicate that the constant current precision is within [Formula: see text]1% in a wide range of universal-input AC voltage from 110[Formula: see text]V to 240[Formula: see text]V and the voltage load range between 2[Formula: see text]V and 8[Formula: see text]V.

scholarly journals Dimmable High Power LED Driver Using Fuzzy Logic Controller

2021 ◽  
Vol 5 (2) ◽  
pp. 45
Author(s):  
Rizky Fatur Rochman ◽  
Eka Prasetyono ◽  
Rachma Prilian Eviningsih
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Constant Current ◽  
Led Driver ◽  
Flyback Converter ◽  
Compact Size ◽  
Wide Range ◽  
Driver Circuit ◽  
Converter Topology ◽  
Lighting Loads

The use of lighting loads is one of the crucial matters which increases every year. The increasing use then leads to the development of brighter and longer-lasting sources. In addition, the conventional use of lighting loads today, which only emit light at its maximum intensity, does not allow the consumers to adjust the brightness level as needed. Consequently, this condition may cause energy wastage. The LED lighting system is gaining popularity as it is widely used in a wide range of applications. The advantages of LEDs, such as its compact size and varied lamp colors, replace conventional lighting sources. The linear setting of the driver topology using the flyback converter was aimed to control the LEDs with a constant current in order to adjust the variation of the LED light intensity. The closed-loop driver circuit with flyback converter topology was designed as an LED driver with a given load specification from the LED string. A dimmable feature was included for adjusting the intensity of the light produced by the LEDs. Eventually, the fuzzy logic controller (FLC) method was applied to the integrated change setting to obtain a dynamic response.

Design of Constant Current Source Based on Pulse Width Modulation

2013 ◽  
Vol 645 ◽  
pp. 418-421
Author(s):  
Li Hui Sun ◽  
Shu Jing Wang ◽  
Wei Chen
Keyword(s):  
High Precision ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Current Source ◽  
Constant Current ◽  
Output Current ◽  
Constant Current Source ◽  
Current Output ◽  
High Conversion Efficiency ◽  
Working Principle

Design of the constant current source based on pulse width modulation, and its working principle are discussed. The design can adjust the output current through pulse width modulation (PWM), and realize micro regulation by feedback output which stabilizes current output. The constant current source has some advantages of high precision, stable work, high conversion efficiency.

Scanning tunneling microscopy of polymers: A status report

1989 ◽  
Vol 47 ◽  
pp. 330-331
Author(s):  
P.E. Russell ◽  
I.H. Musselman
Keyword(s):  
High Resolution ◽  
Scanning Tunneling Microscopy ◽  
Sample Surface ◽  
Atomic Scale ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Status Report ◽  
Tunneling Microscopy ◽  
Research Issues ◽  
Wide Range

Scanning tunneling microscopy (STM) has evolved rapidly in the past few years. Major developments have occurred in instrumentation, theory, and in a wide range of applications. In this paper, an overview of the application of STM and related techniques to polymers will be given, followed by a discussion of current research issues and prospects for future developments. The application of STM to polymers can be conveniently divided into the following subject areas: atomic scale imaging of uncoated polymer structures; topographic imaging and metrology of man-made polymer structures; and modification of polymer structures. Since many polymers are poor electrical conductors and hence unsuitable for use as a tunneling electrode, the related atomic force microscopy (AFM) technique which is capable of imaging both conductors and insulators has also been applied to polymers.The STM is well known for its high resolution capabilities in the x, y and z axes (Å in x andy and sub-Å in z). In addition to high resolution capabilities, the STM technique provides true three dimensional information in the constant current mode. In this mode, the STM tip is held at a fixed tunneling current (and a fixed bias voltage) and hence a fixed height above the sample surface while scanning across the sample surface.

scholarly journals A Graphical Design Methodology Based on Ideal Gyrator and Transformer for Compensation Topology with Load-Independent Output in Inductive Power Transfer System

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 575
Author(s):  
Qian Su ◽  
Xin Liu ◽  
Yan Li ◽  
Xiaosong Wang ◽  
Zhiqiang Wang ◽  
...  
Keyword(s):  
Phase Angle ◽  
Design Methodology ◽  
Constant Current ◽  
Current Gain ◽  
Transfer System ◽  
Power Transfer ◽  
Current Output ◽  
Inductive Power Transfer ◽  
Zero Phase ◽  
Inductive Power

Compensation is crucial in the inductive power transfer system to achieve load-independent constant voltage or constant current output, near-zero reactive power, higher design freedom, and zero-voltage switching of the driver circuit. This article proposes a simple, comprehensive, and innovative graphic design methodology for compensation topology to realize load-independent output at zero-phase-angle frequencies. Four types of graphical models of the loosely coupled transformer that utilize the ideal transformer and gyrator are presented. The combination of four types of models with the source-side/load-side conversion model can realize the load-independent output from the source to load. Instead of previous design methods of solving the equations derived from the circuits, the load-independent frequency, zero-phase angle (ZPA) conditions, and source-to-load voltage/current gain of the compensation topology can be intuitively obtained using the circuit model given in this paper. In addition, not limited to only research of the existing compensation topology, based on the design methodology in this paper, 12 novel compensation topologies that are free from the constraints of transformer parameters and independent of load variations are stated and verified by simulations. In addition, a novel prototype of primary-series inductor–capacitance–capacitance (S/LCC) topology is constructed to demonstrate the proposed design approach. The simulation and experimental results are consistent with the theory, indicating the correctness of the design method.

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