Hello, I’ve been working on this for quite some time, I wanted a boost driver compatible with Anduril and proper moonlight modes but there was none available so I started to learn about electronics and PCB design to make one myself, while browsing boost ICs I stumbled upon the the new TPS61288 which looked really nice for flashlights : small footprint and 15A switch limit, plenty enough for me. I thought of a technique for moonlight too so I got to work. Then Loneoceans showcased his boost driver with basically the same hardware and features so I hesitated to continue working on mine, but I decided to carry on with it as I wasn’t sure he was going to publish a standard sized driver rather than one specific to a flashlight.
Specs :
- 20-22mm (or larger) with components within 18mm, max component height between 2 and 7mm depending on the chosen inductor.
- Single cell input with up to 5A at 6V or 2.5A at 12V outpout.
- Attiny1616 : 3 wires flashing and calibrated temp sensor
- E-switch with Anduril
- High resolution dimming : at least 1:65000, something like a 0.05 lumens moonlight when configured for max power.
- Reverse polarity protection
- RGB AUX LEDs
I tried to pay attention a lot to physical compatibility as to make it as universal as possible, not without some headaches, especially with the large spring pad (10mm) which made routing a bit complicated, going with 4 layers would have probably made it easier. (Also maybe because it’s just second PCB I design)
The largest inductor it can fit is a XAL7070 (7.5x7.2x7mm) for maximum efficiency, in the render it’s a 7030 (7.5x7.2x3), but a smaller one can be used if there is not enough space in the driver cavity or simply if less power is needed, the pads will fit down to XGL/XEL5020 (or other brand parts of the same size) and are away from the center to give more space to the wires if necessary.
The components on the back should be hand solderable (but there are some 0402 passives that I should try to change to 0603), allowing to build it with just a hot plate/frying pan.
High resolution dimming :
To achieve a higher range than the usual 8 or 10bit i.e 1:255 or 1:1023, I use a second current sense resistor allowing to regulate very low currents, I described it in more details here, I haven’t tested this yet but after disassembling a Zebralight I saw they use the same technique, Loneoceans too on the LumeX1 apparently.
So now I need to receive the parts, build it and test it, hopefully it will work
And if you have suggestions I’m all ears.