I’m a huge efficiency geek. Especially in powerful lights - because then efficiency improves not just runtime but also sustained performance.
I’ve been a big fan of buck, boost, buck-boost drivers.
I’ve been a huge fan of XHP35 HI.
It was hard for me to pick a lower efficiency option….but I believe that for A-lights it just just better.
Why?
- Linear drivers use fewer components…and smaller ones
- Driving even a single XHP35 to the max requires a large inductor, interfering with optics
- the sheer amount of board space required is large…A1S should be possible, A4S - maybe, but the smaller variant surely not
- Cost
- Buck, boost drivers are costly, especially the high powered ones
- XHP35 is costly, especially when you want several
- efficiency difference…it’s not so simple
- high power boost drivers are not very efficient, we’ve seen under 90% when boosting a 6V LED (expect less when boosting to 12V)
- linear can exceed that at high power levels, at the cost of falling out of regulation when battery voltage drops too low
- at moderate power levels boost would win, at super-low there’s there’s nothing like resistor…possible with linear, not with boost
- high power buck drivers should be more efficient than linear, though they would fall out of regulation even quicker
- XHP35 is more efficient than any other LED with comparable throw and this is more important than any difference in drivers
- Q8WP is throwier than XHP35, so it deserves to be used as well. But it needs a buck driver. That would be more efficient
- high power boost drivers are not very efficient, we’ve seen under 90% when boosting a 6V LED (expect less when boosting to 12V)
So it boils down mostly to price and size. But efficiency gains are not superb either.