Tom E, yes I figured the 150 levels was chosen as a generally good balance between ramp duration and ‘smoothness’. The only time when the ramp is a little less smooth can be in muggle mode where the ramp length is truncated.
The Buck Boost (at least for the FW3x board) is good up to 3 amps - mostly due to PCB constraints and to keep the design cost down. The FET control pin can also be PWMed, so it’s pretty easy to configure the ramp files to extend the ramp to PWM the FET as well. However, the thing about the FET drive is that it’s literally unregulated. If using a combination of FET + regulated, there will be some sort of jump between maximum regulation and some sort of PWMed FET drive, which will vary depending on the LED and battery used. The same applies to 7135 + PWMed FET.
The idea of unregulated FET drive still is concerning to me from an EE point of view, so I thought it would be best to leave it as a single turbo level. Regardless, this is easily adjusted in the cfg file, so you can certainly transition from max regulated level to some sort of PWMed FET ramp. I have experimented with using a 8bit 15.6kHz PWM and a 10bit 3.9kHz PWM for the Buck Boost (and also for the FET), and I think I prefer the 10bit 3.9kHz PWM – note this does not translate to PWM for regulated output (there’s a caveat for the low moon modes but that’s a different thing), and I think 3.9kHz for most purposes is just fine (only if using FET in PWM mode). This can also be changed in the hwdef file. I’m really not sure what people will prefer, I guess.
Oh and I should mention, the Attiny needs to be able to support >8bit PWM if you want to have 10bit PWM of course... IIRC, the Attiny85 only has 8bit TCPWM blocks, while the 1634 adds a 16bit PWM block. This is why most other drivers have only 255 levels of PWM resolution for their 7135s. I suspect going forward with more 1634s in drivers, we may see more 1023-level PWMs, but potentially at the cost of lower PWM frequency - can be mitigated with a faster external clock, though..
If I had more board space, it’ll be easy to scale up the buck boost (or just use a buck or a boost, quite easily done for very high power levels) and we should be able to get full regulated output with much higher power handling capability. I built a buck converter for one of my high voltage projects which handles about 52kW peak, for example, but that’s another story. I’m not familiar with the Q8 though, and I’m not sure if I have plans to work on that just yet. The 100W boost driver is working, but it's very expensive. The GaN FETs used are $7+ per piece in 1x quantity, and you need 2 of them, plus the rest of the BOM cost. I'm not sure if it's worth it for most people. I had to bypass the entire flashlight body with a copper ribbon from a Samsung 30T cell. The general point of the GXB drivers was to boost from a single cell at very high power levels. If the flashlight was 2S or more, there are a lot more practical, less silly designs, and much cheaper designs that can be done .