Both of you are right, although a linear driver for 2S voltages would be very inefficient and would be at risk of overheating.
Depending on the size of the driver there are already buck drivers for the xhp70 that do what you want. The FX30 in the convoy L6 does 5A from the factory, same for the driver in the S70 but those are both 30mm drivers.
I am looking for something in the 17 to 19mm range for my convoy M1 (MT-G2) and Nightfighter (XHP50.2) that will deliver more with out getting stupid with a full on FET.
6V LEDs use closer to 7 or 8v especially when driven at higher currents, so you won’t get stable output for very long using a 2S battery unless you had a special buck+boost driver that will keep a constant current even when the battery voltage drops below the LED voltage.
A buck driver would be something like 3S or 4S to 6v LED, 2S+ to 3v LED, or 4S+ to 12v LED.
Right now i would like to have boost driver with 2S input and output of about 100-150W and output voltage for 6 x XM-L2 in series, or maybe 12 in series. I have that 12xXM-L monster but can’t find good driver for that. Leds are now 3S2P x 2 and 2S input with FET just won’t work.
A good 1S driver to drive a 6 Volts LED would certainly sell.
Nearly ordered a H1-A from Kaidomain, but it has PWM at a clearly audible 3.6 kHz.
I don’t want PWM at all actually…
I now made a PCB for a 1S 2A max buck-boost converter, but somebody needs to write some code for it. It works pretty similar to loneocean’s gxb20: Oshpark Link
Current range is from 14mA to 2A. Regulator IC is TPS63027, MCU is an ATTiny1634. To build the driver, you need a hot air soldering station or an oven, because the regulator IC is a BGA chip.
This is why I have not pursued making any next gen drivers. We don’t have any firmware for the latest MCU’s. Until a new MCU is selected and firmware is ported over to it, we can’t really improve past what we have been ding sadly. The Attiny’s we have been using are simply too large.
Once some firmware for the 1617 or 1616 mcu comes out, then we can really start moving things forward.
So the real discussion should be what ia the best MCU to adopt?
If people like Mike C, Tom E and Toykeeper can come to a MCU to use with more pins then the AT85 this opens the way for next gen schematics right?
From my non technical and non programmer way of looking at things I hope the costs and availability of the MCU can weigh in for it will make it easier to implement in BLF specials if it is good to source and affordable, each cent helps here.