comfychair-inspired quick+cheap+lazy single-sided 17DD FET-driver (poor man's nanjg92)

It is not that I know for real that these ebay FET's work, they are mentioned by Rbd in wight's 17DD thread as perhaps being suitable as well, wight could not see anything wrong with it. So if you could report that they work and work well, that would be helpful. (anyone else used this FET?)

Thanks for adding extra information on this nice Nanjg92 mod djozz. The main problem seems to be getting these high current capable FET’s.

Does anyone know why comfychair quit BLF all in a sudden? He is one of the great contributors in this forum and I hope he is fine.

While waiting for the ebay FETs from china,
.
http://www.ebay.com/itm/PH4030AL-NXP-Trans-MOSFET-N-CH-30V-100A-5-Pin-4-Tab-LFPAK-10PCS-LOT-/271786806429?pt=LH_DefaultDomain_0&hash=item3f47c18c9d.
.
Ph4030 PDF
.
I ordered one of these from ebay uk, it arrived today,
.
NXP 1R2-30YLD
.
PDF
.
A quick test shows it has very low resistance only 1.55mOhm @ 3.5v Vgs. But it has twice the gate charge, at 32nC, of the fet in the OP, so it may cause problems with the ATtiny. I’ll fit it to a driver next week and report back. My first DD driver is imminent!
.
Oh and this fet is really thin and tiny they say it can switch 100amps that is crazy crazy for something so small.
.

The emphasis of this thread was cheap, right? I was browsing over some old dx-pages, and came across the NANJG ak-47 even cheaper: 2 boards for $2.89 . That makes this driver $2.15 :-)

http://www.dx.com/p/3-6v-5-mode-3w-circuit-board-for-flashlights-1000mah-3-7v-output-7426#.VPuQSoVDtPM

Thanks for the link djozz. I am gonna order some of these and the only uncertainty is about the FET though.

Major has the 'ebayFETs' on order and I ordered them as well. I will make one of these and test :-)

I received the FETS from Ebay (link again, they are 90 dollarcents a piece when sent to the Netherlands ) and tried one out on a AK-47 driver, soldered like in the OP. It gives proper modes and a protected NCR18650B (not a high-drain battery) on an old-gen XM-L bare on an aluminium non-dtp board gives 900+ led-lumens at start up in the sphere. Sounds at least close to direct drive to me :-) I will have to confirm the FET's quality with a proper mod and current and output measurements, but it looks promising.

If it’s good then I am gonna order a bunch of them. Thanks for the effort djozz!

Ebay ph4030 FETs arrived today. Only 8days from Hong Kong! Preliminary test looks good.
.
On paper they appear the same as the Vishay 70n02 fet that was popular. I measured Drain Source resistance 5.1mOhm at 3.5v gate voltage. Not as low as 1.55mOhm of more expensive NXP 1R2-30YLD, but still low. Gate charge is low and they are Cheap and Easily available, and fit well along side the attiny13.
.
Thanks djozz ordered a handful of the DX drivers.

Thanks for the info, Major.

I'm actually surprised that this thread does not attract more attention. It is not that I invented the wheel (comfychair did), but this easy single-sided driver version has everything that wight's beautiful 17DD single-sided driver has (single-sided, DD, low voltage protection, reverse polarity protection, great direct electrical connections from battery to ledwires -better than a 105C-, programmable MCU) but it comes with extra's:

-dead cheap

-only two parts have to be sourced which are available for everyone around the globe

-you can flash new firmware, but if you don't it comes ready with NANJG stock firmware which is not the worst of UI's (high freq.PWM, alright mode groups)

-if you keep the stock firmware it is an easy three minutes build with just a solder iron

But I admit it does not look as handsome as a wight-design on an Oshpark board ;-)

At least it DOES attract my attention. :slight_smile: I know what these things can do, simple yet effective and thanks for helping us to document these information here again.

The only “problem” for me is I am not sure which FET has the low resistance which I can access to. Thank you Major for reporting this to us and I am going to order some of these later.

You got my attention - but as I'm new to modding and electronics, I don't understand half of it :-P

I sometimes start reading topics as they sound interesting, but quickly have to give up because of a lot of technical stuff, and a lot of abbreviations ;-)

Yes, sorry, I'm guilty of abbreviations as well, makes the writing easier and the reading tougher :-(

Perhaps it is nice if someone would write a short history of how the different BLF-drivers have evolved.

NP (No Problem) It just mean a bit more googling. Didn't mean to bring the thread OT (Off Topic)

;-)

Actually no problem at all. I think it's "healthy" having to google some stuff. Takes a little extra time - but the stuff you learn by searcing yourself, rather than having it served, sticks better to memory. I actually hate when people expect to have everything served. So no problem! Alread learned a ton from BLF.

Back to topic :-)

Im sure you have the attention of many others, including me. :bigsmile: Thank you for posting such a great inexpensive mod. This is something that almost anyone can accomplish.

Quick update, I'm excited about this driver mod it's so easy and cheap.

I modded an old knackered ak47 driver last night and the PH4030 mosfet fits easily, it's so tiny it's incredible, it's thinner than the attiny13, I was worried about losing it in the weave of the carpet! The solder pads line up perfectly.

At five amps output it was running cold and had modes. Voltage drop across the mosfet was a lowly 25mV in high mode.

Winner winner chicken dinner.

Im looking for some for duel channel firmware to try this is begging to have a AMC7135 fitted.

Great to hear that the voltage drop over the FET is only 25mV@5A, that is nothing to worry about: the average steel spring has a voltage drop of 250mV at 5A!

I had not thought about that possibility. You can keep the 7135 'around the corner' for that, but you will have to cut the trace to the MCU and air wire it to a different pin I guess (I have not looked into the pin-layout of Toykeeper's dual firmware for the EE A6 group buy driver)

Thanks djozz and comfychairs. I am going to try this driver mod.

Back in 2012 I posted This thread about an alternative way to use attiny 13A/7135 drivers with higher voltage series cells for series LEDs. At that time a few others were doing Zener mods and none of the Oshpark boards had been done yet.

In 2013 I asked Mattaus to design a 10mm driver using the Attiny13A and one 7135. He had created other boards by then and so had others so the Oshpark projects thread was born.

A bit later Brian(WarhawkAVG) asked me to collaborate with Mattaus and Comfychair on another board that combined the Attiny13A with an FET and the BLF DD family of drivers was born. I hadn’t really contributed much in the design of them but I did suggest using the LFPAK56 for its small size and high current capability. We ended up going with the larger FET because Comfychair who was doing the lions share of the testing had a lot of them to work with.

With the concept proven wight began developing designs that took advantage of the smaller FET size to make single sided drivers and that has now progressed to multi-channel drivers.

All throughout this time a bunch of truly inspired people(literally a who’s who of BLF) have been developing and tweaking the code for the 13A mcu to take better advantage of the new board designs.

We now have a member who (RMM, Mtnelectronics) who has set up shop and along with much of what one needs for modding sells many of these designs as well as coming up with new boards on his own.

DrJones, TomE, ToyKeeper, I can’t keep track of all the people writing and developing code and there are a slew of people now with more joining in adding their 2 cents. I didn’t start this but it sure has been fun to be a part of.

Edit- this post is not about claiming any credit, that all goes to Matt, CC, Alex, Brian, and all the others that pushed to get where we are now. It is just how I came to be involved and my perspective on the process.