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djozz
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Thanks comfy,  that is is the kind of 'my level information' that I need to hear every now and then Smile

comfychair
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It will make a lot more sense after you've built a few. Silly

Rufusbduck
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So if you are using the current versions of the boards the new carts are correct but if you use this new method to stabilize the modes you would add an extra cap to the old cart and use a jumper instead for the gate resistor?

The drivers are pretty darn simple, what’s confusing is keeping the different versions straight with up to date carts.

On every one of the modified nanjg boards(both 7135 and FET versions) there are just a few areas of them with easily understood functions. Once you understand those few functions the layout and parts become almost obvious.

B+ power comes into the boards and splits, one part feeding directly to led+ and the other going through the reverse polarity diode to power the mcu and to the voltage divider.

The voltage divider is 2 resistors connected in series going from the reverse polarity diode to ground. Pin 7 of the mcu connects to the junction between these 2 allowing the mcu to monitor the battery voltage as it drops. These 2 resistors drop the entire battery voltage between them passing only a very small amount of current. Most of the drop occurs in the first 19.1k ohm resistor leaving less than 1V left for the 4.7k ohm resistor to dissipate. Pin 7 monitors this smaller voltage and when it drops to ~.5V the mcu changes the pwm signal causing the led to blink and power down.

Pin 6 on the mcu is the pwm pin and sends pulses varying from very short(see ComfyChairs pics above) to constant on and controls the amount of time (duty cycle) that either the FET or the 7135’s are on and conducting current.

When they are on current flows through the board, the led, back to the board, and passes through either the FET or the 7135’s to the ground ring and back to the battery. The convention is actually that electrons flow the other way from negative to positive which is why the ground pin of the FET is called the source and led- is called the drain.

I believe C1 is just a filter on the input power of the mcu to protect it from voltage spikes caused by pwm but it may also have to do with the memory function. I haven’t had to learn about that one so I haven’t. Silly

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

Scott

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Does the BLF15DD suffer from the spike as well?

comfychair
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Rufusbduck wrote:
So if you are using the current versions of the boards the new carts are correct but if you use this new method to stabilize the modes you would add an extra cap to the old cart and use a jumper instead for the gate resistor?

The new shared carts have two 10uF capacitors, one of everything else. Parts required are the same if using either the current, older, or yet-to-come revisions. The new revisions will just add a dedicated spot for the new capacitor, in parallel with the polarity protection diode. Older revisions can use the same 'fix', like so:

http://75.65.123.78/scope/Dsc08268.jpg

Put the cap on the D1 pads, and put the diode alongside the capacitor.

 

WarHawk-AVG wrote:
Does the BLF15DD suffer from the spike as well?

If it's a driver that doesn't change modes correctly without a gate resistor, it's because of the voltage spike issue shutting down the MCU. The 15DDs I built didn't act right without a resistor, so I'd say that's one that needs the extra capacitor. I'm pretty sure Rufus also didn't have any luck running the little IRLM2502 without a resistor.

Rufusbduck
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Apparently Dale was able to use the smaller FET on a modded Tiny10 without the resistor but I wouldn’t count on it.

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

Scott

comfychair
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Well I have pics in the 'scope thread that show the voltage spike even on drivers that change modes reliably, it just happens to not quite reach the point that the MCU shuts down. It's an easy fix and as far as I can tell has fewer drawbacks than using the gate resistors to hide the effects of the voltage spike. Much better to address the spike itself. The waveform on drivers using the gate resistor are just incredibly ugly, like I pretty much always suspected they would be.

djozz
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comfy, if you have a look on the scope of the waveform of an ordinary 105C, would that also have the spike?

comfychair
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djozz wrote:

comfy, if you have a look on the scope of the waveform of an ordinary 105C, would that also have the spike?

Yes it does. Battery voltage while running measured 3.78v. Those peaks are easily above 5 volts.

http://75.65.123.78/scope/stock105C.jpg

That's completely stock 105C hardware, 8x7135s, flashed with the same STAR clicky FW as in the other scope pics of the BLF drivers.

The size of the spike depends on the load being driven by the PWM pin. 7135s are a very different load than the FETs. If the spike doesn't hit the MCU's overvoltage limit, it runs reliably.

comfychair
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I have seen some BLF-DD drivers that are only just a little bit flaky, right on the margin of working right when testing out in the open on the bench, but do OK once inside a light. So these waveforms are likely exaggerated somewhat due to the test setup - battery box, clicky switch, longish wires from the box to the driver, and so on. But what you can know for sure, is that if it works reliably in this bench setup (and the scope shows the spike issue is down to acceptable levels) it will be solid when installed in a light.

texaspyro
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comfychair wrote:
If the spike doesn’t hit the MCU’s overvoltage limit, it runs reliably.

There is no over-voltage limit circuitry built into the MCUs (there is an under-voltage brown-out detector that can be enabled). Over-volt them and they can die. That voltage spike does not appear to be enough to harm the chip, but it may be causing it to reset itself.

comfychair
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On the ones with issues, one thing they do pretty often, other than just shut off completely after a mode change, is they blink and end up 2 modes lower instead of one. It does act the same as if you tap the reset pin to ground.

This is a different driver, no gate resistor, and the original D1/C1 setup, without the extra cap in parallel w/the diode. CH1 (flat blue line, at 6.000V) is after the diode, CH2 (yellow) is B+ before the diode. These voltages are correct, I moved the probes to the contacts in the battery holder and verified with a separate DVOM. Battery no-load voltage was 4.08 - I'm really not cheating here and feeding the driver 6 volts! It's making that extra 2V all on its own.

http://75.65.123.78/scope/CH1-VBAT_CH2-Vcc_diodenormal.jpg

texaspyro
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The spike is most likely coming from the inductive kickback voltage from the emitter wires. When the FET switches the magnetic field in the wires collapses and generates a voltage spike. A cap across the protection diode is not a good way to stop it. Try a diode across the emitter wires at the driver (bar side to LED+, triangle side to LED-). The diode should have a decent current rating.

wight
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texaspyro wrote:
The spike is most likely coming from the inductive kickback voltage from the emitter wires. When the FET switches the magnetic field in the wires collapses and generates a voltage spike. A cap across the protection diode is not a good way to stop it. Try a diode across the emitter wires at the driver (bar side to LED+, triangle side to LED-). The diode should have a decent current rating.
Comfy has a dedicated thread over here where I was just suggesting the same thing.

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)

comfychair
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1A schottky diode (IN5817) between LED+ and LED- had no effect at all. On a driver with the gate resistor replaced with a jumper, the scope shows no change and the driver doesn't change modes reliably.

bushwhacked
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I just built a few 17mmblf drivers with rmm kit, does this voltage spike have an effect on those? I haven’t used them in any lights yet.

P60dropins.com (just a redirect for now)

comfychair
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bushwhacked wrote:
I just built a few 17mmblf drivers with rmm kit, does this voltage spike have an effect on those? I haven't used them in any lights yet.

If it's one of the versions using the gate resistor and it changes modes correctly you can use them as-is.

-----

17DD with the extra cap & resistors eliminated:

http://75.65.123.78/driverhacks/BLF-17DD-capfix.jpg

comfychair
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Oh, and the AOD510 that didn't work before works properly now in the extra cap/no resistor setup. That's why I added it to the Digikey shared carts.

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I'm sure there's history on this, but does the AOD510 MOSFET perform as well as the Vishay 70N02?

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Tom E wrote:

I’m sure there’s history on this, but does the AOD510 MOSFET perform as well as the Vishay 70N02?


We might need to get some current numbers to find out for sure but it may do even better. On state resistance is hard to compare between fets since they are often spec’d at different gate voltages and aren’t exactly the same from one FET to the next.

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

Scott

comfychair
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I don't have a current measurement, but I have checked voltage drop across both in a like-for-like setup. 70N02 = 32.6mV, AOD510 = 41.5mV. Higher voltage drop means higher resistance. So they're not equal, but the AOD510 is readily available and relatively affordable and they're only 'not as good' when compared to a really excellent one.

wight
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And you can buy it Wink (that’s always a plus!)

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)

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Comfy what are you using for the + button on that driver there? Very clean install (as usual). Also very good news about the 510’s! I was really getting worried as I’d been testing different gate resistor values (I have every resistor pack coming from fasttech so I wasn’t gonna give up yet but I tested every value resistor I had in the spare resistor tube and nothing had worked yet so that’s great to see). Thank you for your time/money.

Side note my 858D will be here Tuesday!

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

comfychair
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Just a piece of scrap sheet copper, I think it's around .040" thick. Not much room in that little Z1...

comfychair
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Revision revised again (probably won't be the last time, either)!

dave_ suggested an alternate fix in the 'scope images' thread (post #50, in case the pagenumber thing breaks the link for you). Instead of adding a second capacitor in parallel with the diode (which does work acceptably well), just relocate the one original cap from its original spot between the diode output and ground, to just plain between B+ and ground.

This is the extra-cap version:

http://75.65.123.78/scope/V1.jpg

Gives waveforms that look like this:

http://75.65.123.78/scope/V1-BAT-Vcc.jpg

http://75.65.123.78/scope/V1-BAT-gate.jpg

 Acceptable, and it makes the driver reliable with the gate resistor deleted. But requires an extra capacitor.

 

dave_'s suggestion:

http://75.65.123.78/scope/V2.jpg

Gives you this:

http://75.65.123.78/scope/V2-BAT-Vcc.jpg

http://75.65.123.78/scope/V2-BAT-gate.jpg

Waveforms look better, needs fewer parts, and works just as well.

The capacitor can go anywhere on the board where it can connect between B+ and ground. There are many options on top or bottom of the board that will give the same connections. On the topside, there's a single ground via right beside the four B+ vias at the LED+ wire pad, if you'd prefer that it not be on the spring side of the board.

A larger value capacitor will flatten the oscillation more than shown above, but this works well enough and the part is the same as what comes on the Nanjg boards, for those who are using that as a source instead of buying bare parts in bulk. For those wanting to get more involved, you can change to a larger value cap if you wish. Experimentation required, and probably needs to be verified with your own scope images if you want to try something different.

 

ANOTHER SET of shared carts - same components as before, just with 1 cap per driver instead of 2:

shared cart- BLF-SRKDD | Digi-Key

shared cart- BLF-17DD & BLF-20DD | Digi-Key

shared cart- BLF-15DD | Digi-Key

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I hope you dont mind me posting this here but I got my first Osh Park shipment today. I just need to know now how it all goes together. Smile

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

wight
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Uh-oh! Those spacer boards seem to be missing the center hole?!?

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)

Werner
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Is there a way to order different boards with the same order? I just ordered some things and I had to pay two times…I hope they will send it together.

Rufusbduck
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Werner wrote:
Is there a way to order different boards with the same order? I just ordered some things and I had to pay two times…I hope they will send it together.

+1, had to do that myself and the two sets were fabbed a week apart and shipped separately. They might do overseas differently as Steve just posted an order with several boards that came together.

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

Scott

djozz
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Rufusbduck wrote:
Werner wrote:
Is there a way to order different boards with the same order? I just ordered some things and I had to pay two times...I hope they will send it together.
+1, had to do that myself and the two sets were fabbed a week apart and shipped separately. They might do overseas differently as Steve just posted an order with several boards that came together.

I did three orders right after each other, three separate pay sessions, but they arrived in the same envelope. Apparently the Oshpark software has an efficiency thingy build in, or even perhaps there are real humans involved there somewhere Smile

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