Effects of the traditional model of LED's over the output capacitance of the drivers feeding the LED

What is it about?

The paper deals about the effect of light-emitting diode (LED) modelling in the design of offline drives. The authors use the well-known model of a source voltage and resistance model (SVRM) to analize the effect of this model in the output capacitance of drivers feeding LED's. The offline drive used for the analysis is the flyback converter operating in discontinuous conduction mode. The equivalent circuit is analysed by superposition and the AC circuit is analysed with phasors. The analysis has proven that the flyback converter can be modelled as a current source feeding the output capacitor in parallel with the load. Likewise, the analysis demonstrated that the current ripple is always greater than the voltage ripple when an LED is used as a load. In order to validate the theoretical analysis, a design methodology for the flyback converter with the SVRM as a load was developed.

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Why is it important?

In many drivers for LEDS, the Achilles heel of the drivers is the output capacitance. Since, it is usually an electrolytic capacitor with a short useful life, the use of the appropriate model of the LED helps to reduce the value of said capacitance, increasing the useful life of the driver. without any additional cost

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