Stabilising current driver for high‐voltage light‐emitting diodes

Abstract

High-voltage light-emitting diodes (HV LEDs) possess higher cut-in voltages and works at a high supply voltage. As the specific feature, they can be directly driven via universal utility-line voltages after appropriate rectification. This significantly simplifies the circuit structure and reduces the manufacturing cost. While HV LEDs are driven directly by half-wave rectified DC power source, which is an impure form of DC, their lumen is easily affected by changing the AC voltage source, while only constant current control is insufficient for stable lumen, thus hindering their usefulness in practical applications. This study proposes a simple, however effective, HV LED driver via a proportional and integral current control accompanied with feedforward compensation which is capable of maintaining stable lumen under changing AC voltage sources. Experimental results have demonstrated satisfactory performance in lighting.

Duality approach to the study of switched‐inductor power converters and its higher‐order variations

“…In the three basic current-type of SMPCs [23], the capacitor C is used to regulate the current conversion ratio while the inductor L is the filter of the output terminal. Current-type of SMPCs no longer follow the volt-second balance principle but meets the amperesecond balance of the capacitor C. It means the amount of charge flowing into the capacitor C should be equal to that flowing out of it during one switching cycle, in the steady state.…”

Dimmable flicker‐free power LEDs lighting system based on a SEPIC rectifier using a regenerative snubber

“…To reduce the LEDs current ripple a linear current regulator is sometimes employed [23][24][25][26]. However, to ensure that the regulator losses are not excessive, it is necessary that the difference between its input and output voltages remains as low as possible, preferably on the threshold of regulation.…”

Power quality improvement using bridgeless‐Landsman converter for LED driver

“…There are other requirements for LED drivers as constant current, small form factor, LED junction cooling, high efficiency, efficient dimming, no flicker etc. [3][4][5][6][7][8][9][10]. There are different LED drivers which are proposed to fulfil different requirements [6].…”

“…There are different LED drivers which are proposed to fulfil different requirements [6]. Generally for all LED drivers, PF correction (PFC) and DC-DC converter is common [4,[6][7][8][9][10][11][12].…”