Polyboost driver

[Paulostool]

I was having a hard time searching high Vf boost drivers in a compact circular size that would fit in a flashlight body.

At some point I was convinced that I would not find it ready to buy at the size I wanted, and after some tests with the TPS61500 boost controller I finally decided to learn a new skill and design my first real PCB.

This is how Polyboost very slowly came to life over the last months!


Why Polyboost?
- it’s a 7135-less “Nanjg 105c” driver
- that instead of linear, it is a boost driver
- for lots of Vf (OVP at 25v, tested up to ~20v)
- fed by multiple LiPo cells
- with multiple analog dimming modes/levels (Open source FW’s compatible)
- built for multiple projects
- all of them with multiple laser chips in series
- and multipurpose: it’s also a keychain!
- and last but not least: contains a laser shooting bunny, that is also a duck

Very poly characteristics!


What it is not:
- not cool, this thing gets hot!
- not flawless, this is the first PCB design I sent for manufacturing and of course I made mistakes
- not protected against reverse polarity, I messed it up on the design. (Using a schottky for all the current was a simplistic dumb ideia)
- not my original circuit schematics, this project was heavily based on Giannis open source boost driver, TI reference for TPS61500 boost controller and Nanjg 105c schematics
- not a comercial product, I’m just a hobbyist filling all my free time with an obsession


Main features:
- 22mm of diameter
- up to 4 Lipo cells (18v input)
- 2s slow start
- OVP set at 25v
- Multiple modes: 1% to 100% analog dimming
- 1-mode jumper for no thinking, only full blast (MCU and LDO delete)
- Voltage monitoring and over discharge protection (Nanjg 105c FWs, needs appropriate voltage divider for the number of LiPo’s)
- Used FW: Biscuit.c from trebisky/Convoy repo on GitHub


- Tested configs:
- Runs fine at 1A with ~7.4v input and ~17v output (~80% efficiency)
- Tested briefly at ~2A with 16.8V input and ~18V output


It works!

I’m very satisfied with the results, analog dimming works great up to ~1%!
It can shine the Qualas very gently

The extra planning on decoupling the “smart” and “power” sides was totally worth as I was able to test both things separately, always having the option of removing the MCU completely with a single jumper if it didn’t work.

Now it’s time to finish the first build using it!

 

[Ricker]

Great job! Can't wait to see V2! You attaching a heatsink to the chip as well?

 

[Paulostool]

Great job! Can't wait to see V2! You attaching a heatsink to the chip as well?

No heatsink! Why I’m not doing it??

I’m not confident that this will make it handle the full 3A @20v of the Qualas, but it can help!

I’ll be very happy if I get 2.5A at least for a couple of seconds with the extra thermal mass!

 

[Darktron]

For QuaLas arrays specially the dual stack ones I recommend physically splitting the arrays and powering each with their own driver at lower fV but is not an easy task to split the arrays.

 

[SĤ𝕒∂όⓦŁ𝔸ŜєR]

Your first driver? Congratulations, the mini array is also nice. How powerful is it? There are different models, these replace the old brass banks with, say, 8 or 10 diodes with Gball as a collimating lens! @Paulostool

 

[Paulostool]

For QuaLas arrays specially the dual stack ones I recommend physically splitting the arrays and powering each with their own driver at lower fV but is not an easy task to split the arrays.

I was able to use the same hot plate I use for reflowing the driver boards and led emitters on mcpcb’s.

I just transferred the module from the original board and dropped on an already pasted 20mm copper star board for 9090 leds.
Then it went to the hot plate again, centralized by eye and let it cool down before testing.

The other side is still waiting it’s destiny on the original board

 

[Paulostool]

Getting some more ready for the next projects

 

[Paulostool]

My multi-beam RGB collection is complete, all of them using Polyboost driver

More details on the individual posts.

Blue Penta-beam:

P

Thread 'Blue Penta-beam pointer'

Jan 28, 2026

Last year I lost my hopes on getting a GH04C06X9G for a multi-beam blue pointer, so I began looking for a multi-diode solution.

After seeing how close the new Qualas modules have the diodes mounted, I decided to try focusing all of them with a single big long FL lens

So I got a Nubb38t with 2 banks of 5x 455nm LD’s in series. Removed one of the little lens set and put some zoom flashlight lens in the front.
It did work at most, lots of artifacts but it cleaned a little by masking the raw output before the lens!

Next challenge was driving this in the flashlight body of my choice: a...

• Paulostool
• Replies: 8
• Forum: Blue, Yellow, & Other Colored Lasers

• 

Red Octa-beam:

P

Thread 'Is it an Octa-beam? Or a Quad-dual-beam?'

Feb 5, 2026

Of course I would not stop on the Blue Penta-beam after all the effort put into Polyboost!

My Numb12t arrived and the reds beams look really awesome behind a long FL lens
But lots of artifacts to try cleaning out…

Stay tuned for the build.

• Paulostool
• Replies: 3
• Forum: Red Lasers

• 

Green Tri-beam:

P

Thread 'Triple Green Pointer'

Feb 11, 2026

The Numb12t is composed of 2 submodules:
- 4x2 reds (used on the octa-beam)
- 3x 525nm + 2x 465nm

I decided to use the second half on this project with the blues dormant to create a pure green multi-beam.

I was not that excited with just 3 beams and was also expecting the greenies to be the hardest to fit centered on the MCPCB, because of the blues on the side.
But they were hiding a very pleasant WL surprise: 524nm, 528nm and 533nm! In order!!

When driven low, there is a fourth WL!! I re-measured a number of times and consistently got 4 peaks…

To make things even more interesting...

• Paulostool
• Replies: 4
• Forum: Green Lasers

• 

 

[Paulostool]

More things that Polyboost is not:

- Compatible with illuminated tail switches, they get crazy!
Had to change plans and identify the RGB collection with colored buttons.

- Suitable for common cathode setups, it only work with LS current sensing.
I’ll need to work on a variation with HS current sensing for that.

 

[Z80 Lasers]

I would like to test these out at some point, they look very promising!

 

[Paulostool]

One more Polyboost build still using a Convoy Z1 host. Probably the last one of this collection.

This time it’s not exactly a laser but have two visible blue laser diodes aiming at a phosphorus layer:

Convoy Z1 + LEP emitter

After months of planning, I finally put a Kyocera SLD module on a Convoy Z1! This is using my custom Polyboost driver, joining a collection of other 3 Convoy Z1 RGB multi-emitter laser builds. Here it’s putting 1.6A at 9V, using it for consistency with the other builds and because it have a...

budgetlightforum.com

 

[Paulostool]

Some beam shots of the Kyocera SLD module with the Z1 22mm FL lens.

I’m thinking if a shorter focal length could actually increase the “white laser” effect here by having a smaller initial beam diameter even if divergence increases…

I’ll try to get rid of some of the spill with a black gasket