Shared projects

46mm LDO - SRK Texas Avenger

by Texas_Ace.

2 layer board of 1.82x1.82 inches (46.15x46.15 mm).
Shared on June 15th, 2017 19:23.

TA46 LDO - 46mm Skyray driver that has an LDO setup with a single contact*

This driver is basically the same as the TA46 LDO 2s or 4S except it has a single contact pad. This means that you will need to use a cell carrier to get the input voltage setup for 2s or 4s. It can accept and work with 1s, 2s, 3s, or 4s input voltages as long as the output LED setup matches the input (aka, 6v LED for 2S cells ect).

It is exactly the same layout and driver as the one above except for the contact on the bottom.

OThread link:

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17mm V2 Texas Commander Tiny85

by Texas_Ace.

2 layer board of 0.68x0.68 inches (17.15x17.15 mm).
Shared on March 30th, 2017 14:17.

Ok, I don’t have time for my normal long post explaining every little detail of this driver. Plus with all the advancements coming down the line in driver tech I see bigger and better things coming out this year anyways.

Still this is a good concept and works great so it is worth posting it up.

Basically while this was not the goal, this is an open source LD-3 driver. The difference being that the LD-3 has a better 4 layer PCB and can handle a bit more heat then this driver. The features and basic setup are similar though. This driver also offers the ability to run bistro, which was the biggest reason for making it.

If you like the LD-3 firmware, just buy that and save yourself the time of building a driver by hand.

The credit design of the driver goes to DEL, he did all the technical design work, I just crammed it onto a 17mm driver and made his life harder by demanding every possible option be included. ^:)

So lets start off with the features of this driver:

It offers true constant current regulation without PWM It has a very low dropout voltage, which means it will maintain regulation as long as possible It is very low resistance, offering max power in turbo mode The regulated output can be overridden with a direct FET drive channel. Allowing for normal turbo modes like we are used to. It offers a moon mode and/or indictor LED channel if the firmware supports it. It can be used with either e-switch or clicky firmware It is setup for the new OTSM firmware that flintrock has been working on to remove all the OTC issues It has a large 1206 C2 cap for the OTSM

Now for the limits of the driver:

The short of it is that it gets hot and there is no effective way to cool it with low Vf LED’s. On older LED’s it should work fine.

The longer version is this drive being a linear driver means that it burns off all excess voltage as heat. When you boil it down, linear drivers are basically variable resistors (this applies equally to 7135’s the LD-3 ect). In this case that heat is produced in the FET and has to be dissipated in some way or things will start melting.

Due to the FET not having any way to thermally connect it to the body of the flashlight we are limited to passive cooling via the air and PCB. This is limited to around 2W of heat dissipation. If you fill the driver with thermal cube or pot the driver it could handle more but still 3W would be pushing things.

Now 2W is fine for pretty much all the “last gen” 3V LED’s. They will at most need about 1.5-2W dissipated due to the higher Vf. 6V LED’s could also ok if you avoided mode in the 30-70% range where the FET is hottest.

With modern low Vf LED’s things are very different. Even a single 219C could need as much as 4-5W of heat dissipated to maintain the correct output. Triples or 6v LED’s are even worse. It is simply too much for the FET to handle and it will overheat.

So if you are planning on using this driver, be sure you figure out how much heat it will have to dissipate. You can limit the regulated current to reduce the heat and then use the turbo mode with PWM for higher power outputs, this works fine even for low Vf LED’s but is also not that much of an upgrade over a normal FET+1.

Firmware options:

It is setup around the pinout of bistro. Bistro does work with it as is if you install an OTC on the SW pad. The flintrock version of bistro with OTSM should work on it as well but it is not tested.

Parts list:

The part list is included in an excel file in the oshpark download here : “Texas Commander 17mm download”:

Here is a screen shot of that list, there is also a calculator to figure out the resistors needed for your desired current. This file was put together by DEL.


So now for the driver itself:

Here is the oshpark link :

It uses an opamp for the regulation circut. It gets a PWM signal through a DAC as the input and then regulated the output without PWM according to this input.

It has a separate channel for moon mode via a resistor, it will need firmware with voltage compensation to keep moon modes somewhat stable but you can also get ultra low moon modes.

Another channel is for the direct FET control for normal PWM control of the LED.

It has been tested by both me and DEL and appears to work great, it regulated the current fantastic. Just make sure you try to stay under ~2W of heat max, 1.5W is better. You can do this by lowering the amount of current it regulates and taking care of higher modes with PWM via the FET directly.

*Here is the schematic: *


Here is the driver mostly populated:

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Here is the driver empty:

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Light saber 4 channel 25.4mm 7135 driver

by Texas_Ace.

2 layer board of 1.00x1.00 inches (25.50x25.50 mm).
Shared on February 19th, 2017 16:46.

This is a prototype 7135 based driver for a light saber. It supports 4 channels with a tiny25 MCU

The resistors are 0805 footprint, the diode is SOD323. The parts list is the same setup as the Texas Avenger driver series.

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17mm V1 Texas Commander Tiny25

by Texas_Ace.

2 layer board of 0.68x0.68 inches (17.15x17.15 mm).
Shared on January 11th, 2017 15:41.

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17mm LDO Texas Avenger Driver

by Texas_Ace.

2 layer board of 0.68x0.68 inches (17.15x17.15 mm).
Shared on November 30th, 2016 16:17.

Info thread for this driver is here:

Ok, the idea with these drivers is that I can order them from OSHpark and keep them on hand for any build I may desire.

The real key feature is the 3 channels combined with bistro and Narsil firmware to give you nearly endless options when it comes to UI.

I find that the single 7135 is a great regulated low mode, even for high powered triples. Also a must for truly low moon modes.

The FET is obviously for turbo and works great at getting the most lumens possible.

The bank of 6-8 7135’s is where things change from your normal FET+1 setup. This bank allows for a great non-PWM, regulated high mode on most lights and you can simply leave some 7135’s off to adjust it to your exact liking. Or if you need the space leave them all off and you can then clear any retaining ring you may desire.

Here is a feature list

  • The latest FET + 7135 circuit that DEL scoped out and improved
  • Full copper pour over the board to improve heatsinking of all the components
  • 3 fully PWM channels, 1 to a LFPAK56 FET, 1 to a single 7135 on the top of the board and the last goes to a bank of 7135’s on the bottom of the board.
  • Lots of edge clearance on the large drivers
  • Large LED+ wire pass through, suitable for 20-18 gauge silicone wire, even larger if teflon coated wire.
  • Bleeder resistor for lighted tailcaps
  • Zener pads for higher voltage applications
  • Attiny85 ready for all but the 17-19mm versions.
  • Toykeepers amazing Bistro firmware :
  • Thermal management with the bistro firmware!

So now to the Drivers themselves, they are designed around the parts list from DEL.

R1 : 22 k (or 220 k for e-switch lights, like you have been using) R2 : 4.7 k (or 47 k for e-switch lights) R3 : 100 k R4 : 47 ohm R5 : 4.7 ohm BR : 450-650ohm (optional, only for lighted tailcaps)

C1 : 10 uF C2 : 10 uF

Switch: pads for momentary e-switch

U1 : SOIC-8 for the Attiny85, the 13, 25 & 45 also fit on them U2 : LFPAK56 MOSFET (aka, “FET”). PSMN3R0-30YLDX is a popular cheap option, the SIR800DP is better but costs more.

LDO : designed around the LT3009EDC-5 or LT3009IDC-5

7135 : Standard 350ma or 380ma 7135’s can be installed on these pads. I prefer 350ma myself. You will need to clip the center pin of the top side 7135 if you plan to use a bleeder resistor. The 7135’s can be purchased from or

The resisters are all 0603 package (but you can use 0805 if you desire, just have to be more careful when building the driver).

Diode and Zener are both SOD-323 package.

The C1 cap is 0805 in all cases. C2 is 0603 in all cases (0805 could be used). The OTC is 0603 in the 17mm version and 0805 in the others, this is to make e-switch conversions easier.

You can fit 0805 on the 0603 pads if you are careful but if ordering new components, might as well go with 0603. The same can be done in reverse, you can put 0603 on the 0805 pads.

Here is a DigiKey shopping cart with the components I used, there are both better and also cheaper options available if you want to pick out your own, so this is just for reference I like getting a bit tighter tolerance OTC as it can help when things get hot for example).

The items with a quantity of 1 have multiple options that you will need to pick from in the cart. These are the FET’s and MCU. The SIR404 is the better FET but costs over twice the price, the NXP works just fine for most things. The other are the Attiny version that you want. As it stands right now you need the Attiny25 for Bistro and the Attiny85 for Narsil (aka, e-switch). You can also get the MCU/FET from RMM as well for a bit less money.

Also note that the cart includes both 0805 and 0603 OTC caps, you can remove one if you desire. The 7135’s are not included in this shopping cart as I don’t think digikey sells them, they are best ordered from links above.

The firmware that can be used with this driver is the Bistro Tripledown variation which can be found here:

The downloads from OSHpark includes the source files for diptrace for anyone that wants to play around with it, along with pictures of the drivers assembled from diptrace to make assembly easier and a schematic for each one.

Here is the schematic that is used for all of them (save for the number of 7135’s of course).

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