The Buck Power Converter is a complex little device, but its function is somewhat simple. To describe it in layman's terms, it basically takes an energy source and switches it on and off. During the "on" state, the energy is stored in an inductor and during the "off" state, the inductor releases the energy to the LED. The ratio of "on" and "off" time is called the duty-cycle. For example, a 25% duty-cycle would pass to the LED only 3V from a 12V source. All we need to do is control the duty-cycle according to the input voltage and we get constant current feeding our LED.

The Buck Power Converter controller does this by monitoring the current to the LEDs through a current-sense resistor and adjusts the duty cycle either up or down to correct the current in order to match the LED optimal current requirement.

This way we can push the envelope on the brightness of the LEDs without worrying that the source voltage fluctuations will take us past the maximum rated current of the LED and end up with a fried LED cluster.

This looks really great, but there is one last issue to deal with before we get the brightest marine grade LED replacement bulb: the BULB itself, the packaging!

We need to package our clusters in such a way that we achieve the maximum output possible in a real small package while ensuring maximum life expectancy as well. I'm sure at this point you remember HEAT! How can we pack lots of power in a small cluster and yet not overheat the bulb?

Most interior marine lighting applications use a 10W G4 bulb, which is quite compact, so the fixtures tend to be small as well.

The replacement LED cluster bulb must be very small to serve as a retrofit for the original halogen bulb. It also has to produce similar output and color to the original halogen, and still be able to dissipate heat. This ends up being quite a challenge.