Oshpark Projects

1808 posts / 0 new
Last post
wight
Offline
Last seen: 1 year 7 months ago
Joined: 11/27/2013 - 16:40
Posts: 4969
Location: Virginia, USA

comfychair wrote:

Hang on… can I just jumper something like 6v onto the gate pin from 2x CR123s, using the normal 18650s to the LEDs? With the MCU ‘off’?

For the purpose of measuring Vdrop at 100% duty cycle? Good idea, but that will exceed the absolute maximum rating for “Voltage on any Pin except RESET with respect to Ground”: -0.5V to VCC+0.5V

So now that I think about it, here’s what you can achieve with jumpers if you are so inclined:

  1. jumper the protection diode to pickup 0.2v
  2. then jumper VCC to the PWM pin to pickup another 0.7v-1.0v on top of that

And that’s not nothin’. Smile

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

wight
Offline
Last seen: 1 year 7 months ago
Joined: 11/27/2013 - 16:40
Posts: 4969
Location: Virginia, USA

Thinking about it a little more, let’s go for a bonus round. Instead of doing both jumpers, just stick your DMM on the protection diode and confirm that it’s dropping <0.5v. If so you are good to go on jumpering directly from BAT+ (which would be Vcc minus <0.5v) over onto the PWM pin / gate pin.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

djozz
djozz's picture
Offline
Last seen: 12 hours 46 min ago
Joined: 09/07/2012 - 17:04
Posts: 17993
Location: Amsterdam

wight wrote:
scottyhazzard wrote:
djozz wrote:

Talking about a 17mm DD family.....

As an end user of driver boards without experience on designing board lay-outs or the ability or will to program MCU's, but with a lot of enthousiasm for using the DD-boards....

for the small light mods I usually do, it would be really nice to have a 17mm (and 15mm) DD board with no components on the battery side (even not a few tiny resistors)

My sentiments almost exactly. I am willing to sacrifice some beauty for functionality. We are the only ones that will look at the positive terminal and see the presence or absence of chips and have an opinion. I suppose it is analogous to a woman in pretty matching underclothes- perhaps no one will see them but she knows that they are there and it makes her feel happy. I would like to take this opportunity to thank you guys again for all the work you are doing for these projects. I only understand a fraction of what you say but I enjoy the progress you have all made and shared with all of us. Thanks.
My latest driver project can be used that way. With just an FET you can ignore all the warnings about needing a custom firmware... just pay attention to the warnings about how hard to build it will be. As I say in the thread, it should not be quite as difficult as it looks - but it's close. It does use all 0805 sized components, so you can use what you rob from the Nanjg 105c, but since I bypass the protection diode you'll want to use a different value for R1. Pads are available for either DPAK or LFPAK56 MOSFETs. "+17mm DD+7135 -- linear regulated driver w/ FET turbo+":http://budgetlightforum.com/node/32318 As you can see, there are nothing but 7135's on the bottom. The entire bottom of that board could just be deleted and replaced with one big BAT+ pad. For the extra 0805 components (R1, gate resistor, gate pulldown resistor) you can just get them from Chinese eBay vendors 100x for a buck or whatever.

I did see your project but did not realise that the board could be used like this Smile Sooo, if you replace the bottom by a big +pad and a fat -ring, the one-sided 17mmDD board would be almost there, but the reverse polarity protection would be lost because there is no space for the diode?  But reverse polarity protection is a very useful feature (I do insert batteries the wrong way every now and then), I am not sure I would like the board without it.

(always complaining Tongue Out)

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

That board has only 7135’s on the bottom. D1 is on top between the mcu and the FET.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

djozz
djozz's picture
Offline
Last seen: 12 hours 46 min ago
Joined: 09/07/2012 - 17:04
Posts: 17993
Location: Amsterdam

Rufusbduck wrote:
That board has only 7135's on the bottom. D1 is on top between the mcu and the FET.

Ok, sorry, I switched on my brain and dived a bit into the board, now I see: the protection diode is there. So do I understand correctly that the place where the trace starts that the MCU uses for the voltage measurement for LVP is different from the 105C, namely on the other side of the diode, and this must be compensated either by the firmware or otherwise by using a different R1? Can this also be solved by cutting that trace and make a bridge from the trace to the other side of the diode? 

wight
Offline
Last seen: 1 year 7 months ago
Joined: 11/27/2013 - 16:40
Posts: 4969
Location: Virginia, USA

djozz wrote:

Rufusbduck wrote:
That board has only 7135’s on the bottom. D1 is on top between the mcu and the FET.

Ok, sorry, I switched on my brain and dived a bit into the board, now I see: the protection diode is there. So do I understand correctly that the place where the trace starts that the MCU uses for the voltage measurement for LVP is different from the 105C, namely on the other side of the diode, and this must be compensated either by the firmware or otherwise by using a different R1? Can this also be solved by cutting that trace and make a bridge from the trace to the other side of the diode? 

Yes, you understand correctly.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

djozz wrote:

Rufusbduck wrote:
That board has only 7135’s on the bottom. D1 is on top between the mcu and the FET.

Ok, sorry, I switched on my brain and dived a bit into the board, now I see: the protection diode is there. So do I understand correctly that the place where the trace starts that the MCU uses for the voltage measurement for LVP is different from the 105C, namely on the other side of the diode, and this must be compensated either by the firmware or otherwise by using a different R1? Can this also be solved by cutting that trace and make a bridge from the trace to the other side of the diode? 


That change in the trace layout was to allow the voltage divider to see the full battery voltage even after a Zener mod so that lvp could be made to work again with just a change in R1. It means that the 19.1k value for R1 isn’t quite right for single cell operation though.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

Tom E
Tom E's picture
Offline
Last seen: 5 hours 50 min ago
Joined: 08/19/2012 - 08:23
Posts: 14685
Location: LI NY

I assume the BLF15DD V3.0 OSHPark listing here: https://oshpark.com/shared_projects/lQUEtZcJ, has the wrong value for the R4 resistor? Says 100 ohm, should be 130 ohm? Can Mattaus correct that?

So the "Revision 2" has no limiting resistor while the V3.0 does. This is a little confusing between V3.0 and Rev 2 - different nomenclature - I'm not even sure if the rev # pertains, because one version has an option while the other doesn't. I wish rev #'s could be put on the silk screening somewhere, because I have mutiple board rev's all over the place... Are there any recomendations for R3 values if we want to limit current? Is anyone doing that? There's no BLF15DD discussion thread, so no source of info on this board.

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

The limiting resistor is just a resistor that goes between the FET and ground. Knocks the current down a little or a lot, depending on... everything. The idea was stolen from the generic little drivers like these:

http://75.65.123.78/driverhacks/Dsc07643.jpg

R300 is the limiting resistor, 0.3ohm. Most of the time you'll just replace it with a jumper anyway. It's still direct drive, meaning the output is determined by the input voltage and the LED's Vf, the resistor just reduces current across the board. You could do the same by using a PWM value of less than 100% (and scaling the other modes down to match).

The value for the gate resistor at R4 should be the minimum value that lets the mode changing happen like it's supposed to, whatever that number turns out to be (that goes for all these drivers, no matter which size or version). 130 is just a conservative starting point mostly guaranteed to work. If it works with a smaller value, you should use a smaller value. If it works with none at all, you should replace it with a jumper. Using a higher value than the minimum required makes the FET's life much harder (slows down the switching speed, and generates unnecessary heat while the FET is in that not-on-but-also-not-off inbetween region).

Tom E
Tom E's picture
Offline
Last seen: 5 hours 50 min ago
Joined: 08/19/2012 - 08:23
Posts: 14685
Location: LI NY

Thanx comfy - planning on using a couple of these on those AA size cheap zoomies (http://budgetlightforum.com/node/25402), so don't want too crazy of amps.

Helios-
Helios-'s picture
Offline
Last seen: 1 year 10 months ago
Joined: 01/18/2012 - 21:12
Posts: 2099

1,000


Counterfeit 18650s, 2,<a href=“http://

Cereal_killer
Cereal_killer's picture
Offline
Last seen: 1 year 9 months ago
Joined: 07/22/2013 - 13:10
Posts: 4005
Location: Ohio

Tom just an FYI, if you don’t want to use a limit resistor on that version of 15dd you must use a jumper otherwise the FET’s source pin has no connection to ground.

Personally I find the newer 15’s to be much better overall, I “limit” them by setting lower PWM levels, never liked the idea of the limit (sense) resistor.

 RIP  SPC Joey Riley, KIA 11/24/14. Now I am become death, the destroyer of worlds.

Tom E
Tom E's picture
Offline
Last seen: 5 hours 50 min ago
Joined: 08/19/2012 - 08:23
Posts: 14685
Location: LI NY

Well, PWM's have their issues - so I'd rather keep 100% usable. I'm having a really tough time programming this board. The resistors to the right of the MCU are too close. Finally got one programmed by filing down the sides of the clip, but the other just won't program no matter what I do, and even the clip looks perfectly seated. Boy these are a PIA... I think I read others struggling with programming because of clearances - not sure if it was the BLF15DD or not. I'll have to remove the resistors and see if it will work then. Might as well try something because the board will be useless with no firmware anyway...

texaspyro
Offline
Last seen: 2 years 3 months ago
Joined: 04/29/2011 - 12:43
Posts: 4593
Cereal_killer wrote:
I “limit” them by setting lower PWM levels, never liked the idea of the limit (sense) resistor.

PWM only limits the average current, not the peak current that occurs with each PWM pulse. If the pulse currents are too high, you could fry an LED.

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

Hi Tom, you might want to pick up a Nanjg programming board and preflash the driver before you solder it in. The smaller drivers were too crammed for space to allow for clip clearance. The board will save wear and tear on your clip making it last longer for the drivers it will fit.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

Tom E
Tom E's picture
Offline
Last seen: 5 hours 50 min ago
Joined: 08/19/2012 - 08:23
Posts: 14685
Location: LI NY

Thanx Scott! Actually I got the BLF15DD boards working! I did end up removing the 2 resistors, then I could program it. The other board I build up and could program. Think for me, I'd be ok with doing the parts reflow in 2 steps - seems to work ok for me. Actually I think I got those OSHPark boards - but didn't get a setup to use them.

 My $3.xx "slim" mini CREE AA zoomie is sure zoom'n with a BLF15DD and a XP-L V6 on a 16mm Noctigon (sanded down)! Smile

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

I have a separate thread with oscilloscope images of the gate signal on the FET drivers, here: http://budgetlightforum.com/node/32506

With 130ohm gate resistor (PWM = 12) :

http://75.65.123.78/scope/screenshot.01-07-2014%2004.10.11.jpg

Gate resistor bypassed:

http://75.65.123.78/scope/screenshot.01-07-2014%2004.09.54.jpg

 

I'm a complete 'scope n00b, so any tips/suggestions are welcome, including hardware combos to test and what to measure.

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

CC, I checked out your thread. Good stuff and hopefully we can all learn more about these drivers. Would you like me to put a link in the FET board header? You might want it linked in the various FET discussion threads as well. Be nice to verify that the signal bounce is the cause of the erratic behavior and not something intrinsic to each different FET.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

I am only able to guess right now about the weird bounce being the cause of erratic behavior, still have lots more configurations to look at before the fog will begin to clear. Specifically, what does the waveform look like on the SRK-DD boards, which have never had issues running correctly without the extra resistors. The overall trace length on the V2-up 17/20DD is longer than the SRK even when the 17/20's resistor is replaced with a jumper. I also have some of the first version 17DDs with the super-short trace and without the resistor pads, that would be an interesting comparison too. And then there's all the hardware variations and how they work with different firmware versions... like does the waveform look the same for fast-PWM luxdrv and fast-PWM STAR clicky and fast-PWM STAR momentary?

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

Your nanjg “east 92” should also be on that list.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

WarHawk-AVG
WarHawk-AVG's picture
Offline
Last seen: 1 year 4 months ago
Joined: 01/04/2014 - 06:47
Posts: 5071
Location: H-Town

Rufusbduck wrote:
Your nanjg “east 92” should also be on that list.

Isn’t that what the BLF 17DD is, a re-do of the Nanjg “manual” build?

A purpose build nanjg east92

Rufusbduck
Rufusbduck's picture
Offline
Last seen: 5 months 4 weeks ago
Joined: 04/04/2012 - 15:34
Posts: 10389
Location: Golden state

Yes but his original mod didn’t need the gate resistor.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

WarHawk-AVG wrote:
Rufusbduck wrote:
Your nanjg "east 92" should also be on that list.
Isn't that what the BLF 17DD is, a re-do of the Nanjg "manual" build? A purpose build nanjg east92

List of things to look at with the scope, not list of Oshpark projects.

WarHawk-AVG
WarHawk-AVG's picture
Offline
Last seen: 1 year 4 months ago
Joined: 01/04/2014 - 06:47
Posts: 5071
Location: H-Town

comfychair wrote:

WarHawk-AVG wrote:
Rufusbduck wrote:
Your nanjg “east 92” should also be on that list.
Isn’t that what the BLF 17DD is, a re-do of the Nanjg “manual” build? A purpose build nanjg east92

List of things to look at with the scope, not list of Oshpark projects.


DOH!
comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

See post #1045 for current status - new version that no longer requires an additional capacitor, but instead just relocates the single original cap


ATTENTION

Gate/pulldown resistors no longer needed on the 15/17/20DD drivers (and though the SRK-DD technically works as-is without the resistors, it likely has this same voltage spike issue, it just happens to not be as severe, so this same fix needs to be applied on that one as well).

In the normal build of these drivers, there's a HUGE voltage spike at the MCU's Vcc pin #8 when the FET turns off. Up to 6v or higher... and if it goes too high, the MCU's overvoltage protection kicks in and it shuts down until power is removed. It also puts 6v onto the FET's gate, but that's a result of the voltage spike issue, not the cause. This is what it looks like on a driver with the gate resistor bypassed with a piece of wire (blue trace is the signal at the FET's gate, yellow is the battery voltage (the signal looks the same when measured either before the diode at B+, or after the diode at MCU's Vcc):

http://75.65.123.78/scope/gate-Vin-nocap.jpg

 

This is what happens if you place another 10uF/16v capacitor in parallel with the polarity protection diode, no other changes:

http://75.65.123.78/scope/CH1-gate_CH2-VBAT.jpg

That's not perfect but I wouldn't expect it to be, and as long as it stays in the less-than-6v safe range it doesn't matter. Problem solved.

See post #1045 for current status - new version that no longer requires an additional capacitor, but instead just relocates the single original cap

WarHawk-AVG
WarHawk-AVG's picture
Offline
Last seen: 1 year 4 months ago
Joined: 01/04/2014 - 06:47
Posts: 5071
Location: H-Town

Would a resistor in series help? That capacitor sure does smooth out the pulse to the capacitor, would a larger capacitor smooth it further (or were you staying with the off time cap for commonality)

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

The off-time cap is 1uF, the 10uF is the same part as used as the main cap at C1. I don't think any value cap will totally eliminate the oscillation even if big enough to no longer fit inside a flashlight - and as long as it isn't a spike high enough to trip the attiny's overvoltage protection I really don't care. There are lots of hardware combos that work fine with less-than-perfect waveforms on various parts of the circuit. It just has to work, not look perfect.

djozz
djozz's picture
Offline
Last seen: 12 hours 46 min ago
Joined: 09/07/2012 - 17:04
Posts: 17993
Location: Amsterdam

I love what is happening here, improving the BLF-boards!

However (sorry for bringing it up again, I repeat myself I think Embarassed), I think it is also a service to enthousiastic end-users of the boards that they have access to these boards without having to dive into the electronics side. Tom already did an attempt by starting a thread about the 17mmDD board, and that thread showed directly how complicated it is for non-electronics expert flashlight hobbyists to understand how to just make one of those drivers without knowing all kinds of electronics stuff (for me, I can place the parts and reflow anything and live happy ever after with these great boards, but would not know exactly what is going on)

So I hope that all these great improvements to the BLF-boards are followed every now and then by a clear manual for dummies, like a picture of the current best led board with the right parts soldered in the right places (and cleaning up of old pictures of versions that did not work wel). Personally I would like to see scavenge information on the parts lists (like: 'also from 105C' , or: 'from old sk68 driver' , ) because there's no Digikey-like seller in the EU, every order of new parts comes with 25 dollar shipping.

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

Everything from a 105C, except the 7135s of course, is the same as on the BLF-15/17/20DDs. The 17 & 20 use a big TO-252 (also called 'DPAK') FET, the 15DD uses a tiny little SOT-23 FET. These were all designed to use the same components as the 105C in the same circuit design, on purpose. Same resistors for the voltage divider (4.7K & 19.1K), same capacitor (10uF/16v), same polarity protection diode, same MCU.

To fix the voltage spike thing you'll need a second 10uF capacitor, but it's the same part with the same specs as the main capacitor used on the 105C.

To add the off-time function, you'll need to flash the off-time firmware and a different capacitor, a 1uF/16v, placed between MCU pin #2 and ground (here, cheaper than retail even with price breaks, worldwide shipping): http://www.ebay.com/itm/181283883536

 

There are plenty of threads already showing the traces underneath a 105C to figure out what connects where. The circuit is the same on the BLF drivers, the components are just in different locations. But the same parts connect to the same places.

comfychair
comfychair's picture
Offline
Last seen: 5 years 5 months ago
Joined: 01/12/2013 - 05:39
Posts: 6198

See post #1045 for current status - new version that no longer requires an additional capacitor, but instead just relocates the single original cap

 

Updated shared-cart links for BLF drivers:

BLF-15DD: http://www.digikey.com/short/dcdj7

BLF 17DD & 20DD: http://www.digikey.com/short/dcndn

BLF-SRK-DD: http://www.digikey.com/short/dcdtq (last two items, the inductor & big schottky diode are optional - but if you want to use the inductor, you must also use the diode - either both parts together, or neither) (*note: this 5A/40V diode is a different part than used in earlier lists but is interchangeable, the old one is currently out of stock)

Those are parts lists for ONE driver. Adjust quantities to suit.

Please hold off on ordering these boards from Oshpark, they all need a new revision to add a dedicated spot for the second capacitor and to eliminate the gate & pulldown resistors. The parts lists will not change from what's shown here though. If you already have older revisions they can be used safely, just put the second capacitor where the diode goes, piggyback the diode onto the side of the capacitor, and replace the gate resistor with a jumper wire and skip the pulldown resistor.

I have not built or even looked closely at any of the recent updated Oshpark boards (like, the dedicated zener/resistor versions) so parts lists for those other boards will have to come from whoever has actually built (or designed) them.

 

edit: This is the capacitor for off-time memory builds, if you'd prefer to make a single order instead of some from here and some from over there, etc.: http://www.digikey.com/product-detail/en/C0805C105J4RACTU/399-8001-1-ND/...

 

See post #1045 for current status - new version that no longer requires an additional capacitor, but instead just relocates the single original cap

Pages