Literally never seen that. If anything, buck drivers are generally regarded as more efficient, and FET drivers more powerful, on average, even though for each of those it depends more on design than anything else. Zebralights use boost drivers and are the most efficient lights around, but in general boost is IMO not implicitly better. Are you thinking of “turbo”? (i.e. a high, thermally unsustainable brightness, often outside the usual levels)
linear drivers are usually constant-current - LEDs receive the same current all the time (which depends on the LEDs, could be between 1 and 12+A), and brightness is controlled through changing the voltage.
I’m more used to opamp-based linears, but as I understand it, the 7135 chip will allow constant-current until the battery is very low, as eventually, as the battery voltage drops, current will increase to compensate, leading to more current to the LED. Too much voltage or current will destroy an LED, so this could theoretically be bad with a fragile LED and too many stacked 7135s.
Not sure what Moon Meteor Storm is, but I’d like to hear more.
Current will not increase to compensate.
Linear drivers such as 7135 always have the same current at the input and the output, unlike boost or buck converters.
As you said, the current is regulated to be constant regardless of battery voltage.
If the led needs 3v at the set current, the excess voltage will be dissipated in the linear driver. That way, the led always receives 3v and constant current.
Moon Meteor Storm is just a flashlight suposedly optimized for bicycles. Now using it with a narrow layered cut-off beam throwy headlight which uses unusually shaped aspheric lens to strech out the beam in a horozontal plane while making upper part to appear as a bright straight line and lower part curved and slightly less bright (originally came with BBSHD motor).
As much as I don’t like marketing lies, It’s not exactly wrong though, most of the time.
With a buck driver in a single cell flashlight (most common) the ouput is limited due to how close the battery voltage is to the LED forward voltage, at some point like with a linear driver the output can’t be regulated anymore and it will decrease as the battery voltage decreases. There are other practical limitations that limit a buck driver output, like the circuit resistance and the maximum current of available buck converter ICs capable of 100% duty cycle, which is 6A as far as I know, higher current buck ICs have max duty cycle limitations, which means higher dropout voltage, for example Convoy’s 8A buck driver only does 8A for a short time when the cell is full.
A boost driver doesn’t have such limitations and higher output can be achieved vs a buck driver, but also vs linear and direct drive when the battery voltage is lower. the most common boost converter IC used in high power single cell flashlight is the MP3431, 21A peak input limit, in practice can be used up to 40W output.
The LED is also something to consider, in a single cell light a boost driver means either multiple LEDs or one/multiple mutli chip LED, which can be driven at higher power and are more efficient.
Well, sure, but the efficiency with equivalent components is virtually the same as with a buck converter, in practice better because of the ICs available. And ofcourse better than linear or direct drive.