This keeps most of the levels pretty stable and reasonably efficient, as far as linear drivers go. But it still has a direct drive circuit for turbo.
In a totally non-scientific qualitative manner, the overall efficiency curve compared to a constant current linear driver looks something like this:
LEDs also change tint according to the power level. This driver attempts to minimize that effect by blending power channels, but it may still be noticeable. The curve for that looks roughly like this:
If I remember to, I suppose I should probably put this info in the first post somewhere.
The color can be effected due to the power delivery. The FET is full power, many amps, and uses PWM which pulses the full power to create the lower brightness levels.
The 7135 limits current, it only allows 0.35A through. So when it’s using 1 or all the 7135 chips fully, there is no pulsing or PWM and the color is slightly different.
It’s a bit complicated for me to follow, but the tint does shift slightly based on the type of power delivery to the led.
Joking aside, my experience is large suppliers like this can usually provide quotes on items they deal with regularly in hours to a day or two during their regular hours, and if they have to work directly with a manufacturer on a special order of something that requires a little bit of special effort, it’s usually not more than a week.
Being that its a Linear + Fet Driver, it should be more efficient with a high Vf LED correct?
The LH351D has a higher Vf than your typical Nichia so it shouldn’t heat up as much right at an equivalent output right?
Last but not least, does this light have a mechanical switch or an electronic switch?
If you define efficiency by led-watts/input-watts then a higher Vf would be better. However I would argue that the most important efficiency is lumens/watt-input and in that scenario you want the LED with the most lumens/amp where the VF doesn’t matter as long as it’s low enough for the circuit to work.
I could have shaved another few millimetres off the length of the light but wanted a decently thick copper heatsink, magnetic tail and tritium vial in the momemtary switch button, still managed to keep it below 100mm.