Custom SkyRay King SRK Driver

It will probably be 2.8A, the 380 mA regulators just are not available at cost effective prices. To boost the current to 3A you would need to add another regulator chip to each channel.

I’m sorry for the silly question but being the inept person I am when it comes to electronics l have to ask. This driver I think is designed for an electronic switch? Will it work with a normal on off tailcap switch?

Nope…

*gives you money to build me one!

Thanks TP. Now I have to learn about electronic switches. I reckon your driver would be a killer in a custom built 3 led light.

It's just a momentary pushbutton, non-latching. Like on a TV remote. The switch grounds a pin and the driver does whatever it's programmed to do until the switch is pressed again.

Thats simple enough. Thanks. I’m interested in the driver as well.

If it works in the SP03 I am definitely in for one. This work is way beyond me, so I would have no idea how it works or why. But it sounds good.

Great driver!! I would get 1 or 2 when they are available!

I got in some new rev PC boards (that did not have the solder mask screwups that OSHPARK’s board fabricators did on the first ones… they monkeyed with several people’s boards on that panel). I built one up with some 350 mA driver chips from Fastech. Seems to work well. You lose about 60 lumens per LED going from 2.8A to 3.05A per LED…

I got a better measurement of the parasitic drain… it averages around 6 microamps… about 666 times less than the stock SRK driver (over 4 milliamps). Should drain 4 x 2600 mAh cells in around 200 years. The stock SRK will drain the cells in around 3 months.

Sounds like you have been busy getting this figured out.

Thanks for all you work :slight_smile:

That is awesome! Weren't 7135s supposed to leak some current when not switched on? Is that not the case, or did you add some type of switch in between the battery and 7135s?

Biggest disadvantage of this driver is that it didn’t show up about 3-4 months ago, in the golden age of SRK :smiley:
Now, with Supfire M6 and Solarstorm/FandyFire Warrior, SRK is fading away…

It looks like only some versions of the chip do that, or perhaps only chips that have been abused in some way?

I've come to the same conclusion. The chips I've gotten from FastTech and gently soldered have been fine.

PPtk

I have noticed that the lead frames on ’7135 chips are particularly fragile. I’ve left behind lots of them when trying to unsolder them. Also broken them when bending the leads down.

The behavior of the chips is not specified under the conditions of having the Vdd pin pulled to ground. Something tells me there is no pulldown on the output FET gate. Without the Vdd circuit being powered on, the gate might be floating. I suspect it is only an issue with chips from some manufacturers.

That could be the Quiescent Current specs they have at 170-200uA?
That is around 2mA for 10x or 4mA for 20x AMC7135?
:beer:

That spec is a boiler plate typical spec manufacturers use when they don’t want to measure the actual value. It takes a lot of megabuck tester time to measure those low currents.

For the AMC7135, it also applies when the Vdd pin is being driven high. The current the chips draw when being operated with Vdd low (assuming the chip is not leaking current through the output pin) is actually in the nanoamps. Going from 1 chip to 24 chips the board current increased less than 0.5 microamps. If the chip is leaking current, it may be a couple of milliamps. Designing a product that depends upon unspecified chip operation is a no-no, but sometimes you gotta do what you gotta do with the parts that are available, and maybe have to live with the consequences of what you actually get.

The same thing applies to things like AVR chip ADC inputs. They spec them at microamps, but I have never seen one draw more than a few nanoamps.

I just got my new XM-L2 U2 SRK from CNQG a few days ago and the parasitic drain is only 1.42mA. Tailcap current on HIGH is only 1.52A, and only 160mA on low. This is the brightest light I have ever had, with Low mode being just a tad dimmer than my previous “bright” LED light. The driver board appears to be glued down so I may order another one when it comes time to put one of your drivers in it; I like this one too much to risk ruining it. I was going to resistor mod this one but not going to chance snapping the board. I was expecting a much higher tail current, not sure what is up.

1.42mA parasitic current is actually pretty darn high. That will essentially discharge a 2900mAh 18650 in 85 days. In just a month, you'll be down to 60% of the runtime you'd expect.