Texas Avenger "TA" Driver series - Triple channel + Bistro or Narsil + Clicky or E-switch - The Ultimate open source driver!

Dr jones uses four PWM channels for his rgbw drivers. He uses the tiny85 though. He hasn’t been around for a while. I’ve been looking for another good firmware for rgbw but there is nothing lik3 his. I hope he stops by and is willing to sell me a few more of his driver.

Yep, that should be entirely possible and would be a good addition to the Q8 if it is not too late for that.

Yep, that was the one I saw doing it. I would love to copy the 4 channels like his in these drivers if TK / someone was up to making the firmware for it. The changes to the drivers would not be that hard, simply move one of the 7135’s to the reset pin.

I am in the process of putting together a 4S driver for the SRK. I have a few projects that would need/use 2s/4s design so figure might as well go 4s since all the XHP’s can be run in both 6v or 12v mode.

I am laying out the Schematic, but having a hard time figuring out how the R5 and C2 components should be placed with the LDO.

The LDO needs a 2.2uf+ cap on the output wire anyways, could I simply replace C2 with a larger value and it do the duty of both the LDO and C2? If I add a second cap would it interfere with C2? I figure we would use a 10uf cap for the LDO, would the extra size negatively effect the role of C2?

I assume the R5 should remain as the first thing in the + side of the circuit.

DEL, any comments?

Yea, Dr J can save an I/O pin by not using the voltage divider resistors and using the internal 1.1v source instead. Neat trick, and I/O pins are in very short supply... Could be then 4 pins can support PWM. yea, look'n over the datasheet, I see a 4th possible PWM channel.

TK uses Timer/Counter 0 for pins #5 and #6, and Timer/Counter 1 channel B for pin #3, and it looks like it can support another channel (A) for PWM.

46mm Skyray King 4S 12V XHP Driver

This one is not a Texas Avenger series of driver simply because at these voltages the 7135 would not be good for anything but moon mode. But it has the same basic setup and I am putting it here anyways lol.

It is a classic SRK driver but setup for 4S 12V LED’s (or 4 LED’s in series). So this is what you want for an XHP35 / XHP50 conversion. It is pretty basic and sparse on the board, if anyone has something creative/funny to put on the silk screen feel free to let me know, got lots of room on the silk left.

Parts list is the same as above except the C2 change along with the LDO addition.

R1 : 220k
R2 : 47k
R3 : 100 k
R4 : 47 ohm
R5 : 4.7 ohm
R6 & R7 : Unused at this time, installed for future expansion options.

C1 : 10 uF
C2 : 10 uF

E-Switch : Momentary switch

LDO : SOT-23-5 form factor 5V LDO of choice, designed around MIC5235-5.0BM5
U1 : Attiny85 for Narsil, Attiny13A for Star momentary
U2 : LFPAK56 MOSFET (mosfet is the technical name, we call them FET around here)

The resisters are all 0603 package.

The caps are 0805 form factor.

Oshpark link : Removed




That was another thing I was curious about, it would make these drivers in particular WAY easier to fit without having the external voltage devider but I assume without the external divider it would be limited to a 1s setup correct?

Just a amateur hack here, so please don’t take my statements to follow as fact. I would think the LDO will drastically change the situation. Check out the data sheet for your LDO. I’m fond of using the LM2936 and it recommends a 10uF Cap on the output pin. Check out this diagram from it’s data sheet:

The LM2936 data sheet has no limitation on the cap size, just a minimum. It also recommends a certain ESR. A .5 to 1 ohm resistor in series with a typical SMD Cap will accomplish that for the LM2936. Here you can see I have 20uF in caps a 4.7uF resistor (Way to high, was just trying it out) on DD driver for 4S cells. I used 47K (R1) and 4.7K ohm (R2) resistors on the voltage divider.

The LM2936 is way too big for our drivers (can handle 40v on input). Just giving a for example case for you to think about.

I figured it would effect things a fair amount but I am not sure how exactly. I guess one thing I didn’t take into account is the 5V output will change things a bit.

I figure a 10uf cap in the place of C2 will accomplish the cap needed for the LDO along with the C2. I have no facts to back that up though.

I obviously have plenty of room to add a resistor to the C2 cap if needed, I can add the pads easy enough and test later of course.

Any other suggestions? I just tossed this together real quick cause I was bored and didn’t want to spend a lot of time on it.

TA, keep the small resistor in front of the first capacitor. I would guess a 10 ohm or so would be ideal. You may even go higher since you have voltage to spare with a multi-S setup. The active regulator does change things, but I expect the ringing to be still there without this R.

You are OK with only the Cout of the LDO, depending on how close to the MCU it ends up. If you do have the space, a 0.1 to 1 uF C2 would be a nice to have.

You may need to bump up Cin to at least 2.2 uF, to prevent the LDO from seeing the FET turn-off spikes. This is where a resistor larger than 10 ohms can help.

I’m not recommending you put a resistor in front of C2. That will depend on your LDO. For the LM2936, it is critical. What LDO do you plan on using?

Whoah!!! I just saw this build and link on OSHPark…

HOLY SMOKES that’s awesome!!!

17 (covered), 20, 22mm variants are “the norm”
Man…so awesome!

It actually hit me this morning a FAR simpler and more efficient way of doing a 2s or 4s setup in a SRK. Kinda hard to explain but I will knock out a prototype setup and see what people think.

Thanks! been wanting to do this for a long time but just never had the time.

If TomE decides to make a Narsil for this type of driver that would truly complete my goal for these save for adding a 4th channel to the reset pin if that is even possible.

Yep, got all those sizes take care of along with a few variations of them as well. Also a 26mm that can be sanded down to ~23mm or so if needed.

I might measure the S70 and L6 drivers along with the DO1 and knock out some in those sizes as well just in case someone wants to swap those out as well, but those would need new firmware to be able to use the e-switch.

This leaves me with the second “issue” for a 4S SRK driver. I would really prefer NOT use an FET with a multi-cell setup. You loose so much efficiency doing that I just find it a waste, plus it is real hard to control current to what you want.

What I really want is a buck driver. I have done exactly zero research into buck drivers for flashlight use.

I know the RMM has a nice buck driver with good specs, a single coil would not hack it but using them either in parallel or multiples of them with each feeding a single LED would work.

Anyone have any good suggestions on components for a 2S & 4S (would prefer to use components that can do either with resistor swaps ect) driver?

Maybe pull the power for the MCU at 4.2v before the series connection?

Yeah, controlling current is a down side if you want less than the cells can deliver to the emitters, but I would think a FET driver would be pretty efficient. Well, other than driving emitters at a high level that is inefficient (due to the emitter’s design) when the cells are fully charged. Maybe you’re thinking about the inefficiency of the 7135 linear regulators when the cells are full?

A typical buck regulator like we use is about 80% efficient when driven hard. Almost all our buck drivers use the same Chinese buck converter (forget name at the moment). These buck converters are fine driving with 2S, 3S, and 4S cells. They will work with 1S cells, but not deliver much current due to lack of voltage overhead. Same with driving 6v of emitters with 2S cells or a 12v of emitters with 4S. Probably will not get much if any regulated run time.

A buck will work nicely for driving a 6v of emitters with 4S or 3v of emitters with 2S or 4S. Then you enough voltage overhead for decent regulated run time.

The HX-1175b driver is cheap enough to be a good donner for components. It has terrible parasitic drain though.

Ding Ding Ding. We have a winner!

This seems like the easiest method for a side by side cell setup by far. No worries about any of the LDO’s, zeners ect.

Here is a quick proto-type I knocked out to visualize it.

The ring on the outside is connected to the 1st cell to give you 4.2V to anything connected to that ground plane.

The FET / 7135 / Buck driver grounds to the 4S negative terminal. Thus giving the LED 16.8V.


More I think about, it seems quite easy to update Narsil to support this triple output. Between what I know, and code, in bistro_tripledown to enable the 3 PWM channels, and TK's level_calc utility for generating the ramping table, that seems to support 3 outputs, I should be able to come up with a pretty good smooth ramping, then the fixed modes look pretty easy to update.

For ramping, it will be different tables, depending on 350 or 380 7135's. I prefer a 350 for the single because of it's lower moon mode, but for the 6 7135 bank, it doesn't matter, but will need to know (I think) what they are when the table is generated. You can also easily tell it how big you want the ramping table assuming a 16 msec update rate. So if you want a full ramp to take 1.5 secs, or 2.5 secs, you can control that via how many entries to spec when you run level_calc, then it's easy to confogure Narsil to match it. I experimented a lot with different table generations til I got, what I felt, looked real good -- this would take a lot of time again, I'm sure, but might go quicker for me now, knowing it a bit better.

I think it’s worth your time, Tom. As long as you don’t mind giving up your indicator LED.

Having a Medium/High/whatever you call it mode that is a consistent pwm-less level no matter the state of charge is really nice. It always annoyed me that my medium modes (the ones I use most) would “droop” so much as my battery wears down when using the FET.