[Oshpark] HQ 15mm/17mm programmable boost driver with ATtiny13A

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HarleyQuin
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[Oshpark] HQ 15mm/17mm programmable boost driver with ATtiny13A

A collection of 15mm and 17mm boost driver boards based on the PAM2803 boost circuit with a PWM controlled FET and an ATtiny13A microcontroller (MCU) for mode programming.

Some time ago @wight spawned the idea of this kind of programmable boost drivers. This led to some development and I thought it might be helpful to consolidate my Oshpark boards and the information about them.

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Status:
HQB15 v3 (15mm, BAT60A) and HQB17B v1 (17mm, SS24) are built, tested and working.
For starters I recommend HQB17B as it allows the easiest sourcing of parts.

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Boost Driver Status Diode Inductor LVP Annotations
15mm
HQB15 v1 skipped BAT60A 4.3mm no first successful build
HQB15 v2 retired BAT60A 4.3mm no tweaked and shared
HQB15 v3 shared BAT60A 4.3mm no more layout improvements
HQB15D planned BAT60A 4.3mm yes SHDN via voltage divider
HQB15M postponed BAT60A 4.3mm no ATtiny13a-MMU / NXP Mosfet
17mm
HQB17 v1 shared BAT60A 5.8mm no 17mm version of HQB15 v2
HQB17B v1 shared SS24 4.3mm no straight swap of FT boost driver
HQB17C v1 abandoned SS24 4.3mm yes
HQB17C v2 postponed SS24 4.3mm yes FT swap with SHDN via MCU-Pin3
HQB17D postponed SS24 4.3mm yes FT swap with SHDN via voltage divider

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Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

Edited by: HarleyQuin on 04/02/2017 - 00:46
HarleyQuin
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Hardware

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Datasheets

Boost Controller: PAM2803
MCU: ATtiny13A
Diode (3A): BAT60A
MOSFET: IRLML6244TRPbF

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Circuit Diagram

This is the schematic for all boards that are shared for now.

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Partlist Overview

This partlist overview is based on the recommendations in the PAM2803 datasheet and the parts that are used in the FastTech driver.

Boost Controller
Diodes Incorporated PAM2803
SOT-23-6

L1
Inductor (L), min. 2.2µH, 4.7µH recommended
DC resistance (Rdc) as low as possible, 2A current rating, size according to PCB used
All commercially available driver with PAM2803 seem to use 2.2µH

D1
Schottky-Diode (D), min. 2A, Vf as low as possible
size according to PCB used

C1
Input Capacitor (Cin)
min. 2.2µF, X5R or X7R recommended
I recommend 10µF
SMD0805

C2 / C3
Output Capacitor (Cout) and Decoupling Capacitor for MCU
I added C3 in parallel to allow easier adding of capacitance
Combined value: more than 10µF, 18µF seem to work, 22µF recommended,
(datasheet says: min. 6.8µF for the boost circuit, but even 10µF are not enough for working reliably with MCU)
X5R or X7R recommended
SMD0805 (C2) / SMD0603 (C3)

R1
Current Sense Resistor (Rs / R)
~0.120 Ohm for 750mA (2cell)
The PAM2803 datasheet has a table for Rs/output ratio
SMD0805

Microcontroller Unit (MCU)
ATTiny13A-SSU
Package 8S1

MOSFET
N-Channel
SOT-23-3

R2
Resistor between LED+ and GND, derived from FastTech driver
(and value might vary with production batch)
150 kOhm (“18D” / “154”)
SMD0603

R3
Gate/Pulldown Resistor (?) between gate and source, derived from FastTech driver
(and value is definitely varying with production batch)
33 kOhm (“333”) / 10 kOhm (“103”)
SMD0603

OTC (optional)
Off-Time-Capacitor
1µF, X5R or X7R
SMD0603

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Board Design Goals in Eagle
- leave enough space for the Pomona programming clip
- place LED wire pads straight across each other
- no components on spring side

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Board Size
Oshpark boards are not covered with copper to the very edge of the board, the fab leaves a rim of 0.3mm bare PCB. That’s why all my boards have their radius increased by these 0.3mm. The boards are 15.6mm and 17.6mm in overall diameter, so the actual copper ground ring is 15.0mm and 17.0mm.
The boards have to be sanded down, but having copper right to the edge
- makes soldering GND to a pill much easier
- helps a press fit driver to make better contact and
- helps with current and heat.

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Assembling a driver
I recommend a reworking station, I use a – quite cheap – Youyue858D+. I consider hand soldering a real challenge on these boards.
This is mainly because the 0805 and 0603 parts are not standard eagle-size but custom made with a reduced footprint. When creating the brd-files I quickly realized that there is not enough space for standard parts.
And when harvesting the components from the FastTech driver a rework station is ideal anyway.

Always check for continuity, or to be precise: check there isn’t continuity where it’s not supposed to be. The parts are really packed together tighly, they only just avoid clearance errors in eagle. So there is a risk for shorts.

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Low Voltage Protection (LVP)
Toykeeper hinted that Eneloops get damaged when drained completely, so an LVP might be useful. The boost circuit continues to suck energy from the cell even if the LED does not light up any more.
LVP comes in 2 flavours: warning and cutoff. Cutoff being the crucial part here. So far the ideas are
- cutting PWM to the Fet
- shutdown the PAM2803 (Pin4 SHDN) via the ATtiny
- shutdown the PAM2803 with a voltage divider at Pin4
With primaries (lithium, alkalines…) a cutoff is of course unneeded, as these cells are meant to be drained. So we need the sweet spot where the LED does not light up any more (when even primaries are not of use in the light) and the Eneloop is yet unharmed.

The boost circuit stops boosting at around 0.9V, the LED starts blinking at this point.
At first I thought this is a kind of warning but it seems it’s simply the controller stopping, the cell regaining some voltage, controller starts boosting again, the cell sags voltage under the load and the controller stops again.

The blinking (together with the obvious dimming of the LED long before this point) is why I think we don’t need an LVP warning. It’s obvious when the cell is low.

So a cutoff at some point below 0.9V would be good to save an Eneloop as long as possible.

But any cutoff would still not be complete, but eat some (reduced) energy: The ATtiny in sleep mode, the PAM2803 in ShutDown, even the voltage divider is an open circuit to the cell. We only buy some time to realize the light is off, but still powered.

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Moon mode
This looks tough for now.
Even at PWM=1 I can’t get lower than this:
I tried 3 frequencies and it’s the same as with linear driver, the higher the frequency the lower the output on low levels.
4.7 kHz (fuse 65) : 25mA
18 kHz (fuse 75) : 15mA
37.5 kHz (fuse 7a) : 9mA
This is with fresh cells of course, and no difference between 1AA and 2AA.

The brightness is fading, naturally, as the cell(s) is(are) drained. Down to <1mA at the end. But this is not what I call Moon. It’s not even a low Low in my book.

37.5 kHz seems to be the highest the ATtiny13A can offer as frequency and I never used it in a driver before. At least whining should then be no more issue. Any other downsides with this high frequency? Other ideas for a lower Low? Suggestions welcome.

Edit: @fixed it made several suggestions in this post.
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Off Time Capacitor
Only yet tested at my Nanjg110 conversion. Should work.
Some timing adaption will surely be necessary as the value of C2 (and C3) will interfere with OTC timing.

For now it’s quite low on my priority list.
For a 2 mode light it’s not needed (and the lack of Moon does not really suggest more modes on a 1xAA light… sheesh).
For a simple off-time-memory (2 timeframes: short/long) the brownout detection should be sufficient anyway, then no OTC is needed.

.

[to be continued]

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

HarleyQuin
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Firmware

I started with an adapted Dr. Jones MiniDrv firmware.
Frequency changed to 18kHz, on-time-memory, 9 modes. This works fine.

The 9 modes were for testing the behaviour of the boost circuit at low PWM levels.
Simply adapt the modes line to something like {1,8,255} for a practical result.

.

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I know some of you out there are hoping for nice firmware implementations, we will surely need help on that. For now I’m trying to lay grounds for the hardware stuff. A fancy UI is way out of my league.

But I already reserved this whole post for firmware and will gladly fill it up with all you can offer. LOL

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

HarleyQuin
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Some History

.

This was my first successful test to combine a boost circuit with an ATtiny13A.
I hooked up a stock Nanjg110 to an ATtiny13A and a capacitor, both remainder of a Nanjg AK47. I added an OffTimeCap between Pin-2 and GND. And I used an IRLML0030TRPbF as FET. I placed the FET on the pads for a 7135, cut the traces and rewired (better: re-blobbed) for the PWM signal from Pin-6.

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I flashed a it with an offtime firmware with 4 modes.
And there was light.


At 18kHz PWM values of 2 – 10 – 40 – 255 resulted in 12mA – 102mA – 198mA – 404mA with a single full and resting Eneloop.

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With 2xAA the boost controller died (blew a tiny fan of smoke) at one of the first mode changes. It’s surely the controller that died, I swapped this single component from a new 110 and everything was working again (with 1AA).
That’s when I took a closer look at the Fasttech boost driver (who has a controller for modes) and the two resistors there seemed to serve as protection.

.

In the meantime I found a replacement diode for the large SS14/SS24. As I looked for 2A diodes I stumbled upon the BAT60A.
Even rated 3A, only 370mV forward voltage, and SOD-323 package. It’s the teeny-tiny component on the right, where the cathode line uses up almost half the component.
I hooked it up in replacement and drained 5× 1AA and 6× 2AA (Eneloops) on this driver, while monitoring input and output current. Works perfectly fine. Even increased output current in 1AA config and efficiency in 2AA config (needs a lower input current to reach the 920 mA).

.

Then I reworked the FastTech driver (comes in blue now instead of green).
MCU changed to Attiny13a (which was pre-programmed)
Some MCU-traces cut (Pins1/4/5)
Rewired: Pin6 to Fet-Gate (red wire)
MCU+ is already connected to V+out
Rewired: MCU- to GND
MCU- of the original driver is connected to Fet-Source/PAM3. This did not work with the Attiny, it wouldn’t change modes.
Rewired MCU- to GND (black wire) and voila: 3-mode boost driver that did survive several 1AA and 2AA drains.

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The first Oshpark board HQB15 v1 successfully built.
2× 2AA and 3× 1AA (Eneloops) drained, about 200 mode changes, all good.
It’s a HQB15 de-luxe with Coilcraft inductor and high value capacitors.
Partlist with used values and the firmware in this post.

.

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Driver height with this inductor is 3.7mm (0.2mm less than with the FT inductor). Now take the new Oshpark 0.8mm boards and you’re down to 2.9mm. That’s 3.0mm less than a Nanjg110.

Enough space around the Attiny13a for the clip after driver assembly.

.

I took the experience from building v1 (it’s really, really tight) and tweaked the design. I skipped sharing v1 and went straight to HQB15 v2.

All future Oshpark boards will be introduced in this thread.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

ImA4Wheelr
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This is really great thread. I feel that it wrong for me to make this post as this thread so well put together. But, on the other hand, I don’t feel it would be right to not express a big thank you. Thank you HQ for you continuous efforts to make programmable boost driver solution available to us all.

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Thanks HarleyQuin. Amazing efforts.

My current and or voltage measurements are only relevent to anything that I measure.

Budget light hobby proudly sponsored by my Mastercard and unknowingly paid for by a hard working wife. 

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

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.

 

Gunga
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I’m not a builder. Can someone build these for sale? Mtn electronics?

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Thx. My pleasure.
Here is the next version of the 15mm boost driver

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HQB15 v3

It’s still the basic circuit (including R2 and R3, no LVP)
I think this is as much as I could get out of this 15mm design, so for now there is no v4 planned.
It’s about time for building and testing.

Notable changes from v2 to v3:
- more GND vias
- GND plane slightly increased
- 3 plus vias moved outside the L1-pad
- some copper pads increased over stopmask
- MCU moved slightly inwards

It’s still 15.6mm outer diameter, so the copper GND ring is 0.3mm smaller than it does look on these pictures.

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Oshpark Link

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When installing into a light it’s crucial that D1, R3 or the FET don’t get electrical contact with the flashlight body/pill. This might be tight and could risk shorting the light.
Same goes with the LED leads (LED+/LED-). Both must avoid GND.
Pin1 on the ATtiny (RST) has no pad on purpose. That way I could move the whole component slightly down to keep pin1 of the ATtiny (VCC!) away from the side.

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Parts size
(more on parts and values see partlist overview in post#2)

Switch: PAM2803, SOT-23-6
L1: max 4.3×4.3mm
D1: BAT60A, SOD323
C1: 0805
C2: 0805
C3: 0603 (optional)
R1: 0805
R2: 0603
R3: 0603
MCU: ATTiny13A-SSU, 8S1
OTC: 0603 (optional)
FET: N-Channel, SOT-23-3

.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

Rufusbduck
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It’s a bit early for that, Gunga, since so far only one prototype has been made so no beta testing with several to see what problems arise and what needs fixing. If interest holds then it’s possible RMM or 3tronics will pick them up. Since you and I can’t fix very much we need these to be more thoroughly worked up before it’s worth it for those who can to try more than a few at a time.

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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^ This

I’m shelling out all I can to give others options to step in.
But I consider these far from ready.
I tried to point out the lines where we stand in the “4 OPs”

Atm I can spare more time at the PC than at the rework station, so there are more boards than testing on my side.
Toykeeper’s motto is: release early, release often. I’m working on it. – nod -

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

fixed it
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It is beautiful Smile Both the finished v1 board and the layout for v3. They make me wish I had the time and equipment to build one, even though I don’t understand half of what is going on in there and wouldn’t know what light to put it into Big Smile

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Thank you for the in depth history, I for one find it both interesting and helpful in furthering my understanding. Why the change in capacitors from the FastTech board? I understand the reasoning on the inductor but is it just to get better quality caps or to be more certain if the values?

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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Oh sorry. Desperate for a good driver and jumping the gun. Smile

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fixed it wrote:
It is beautiful Smile
Thx. And we’ll find a light for you to put it in Wink

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Rufusbduck wrote:
Why the change in capacitors from the FastTech board? I understand the reasoning on the inductor but is it just to get better quality caps or to be more certain if the values?
I just wanted to play it safe.
1. Wight himself wasn’t sure whether Cout (=C2) of the boost circuit is enough to act as decoupling for the ATtiny. That’s why I added C3 in 0603 footprint to at least give the option to add some capacitance.
2. The FT driver has (iirc!) 10µF as C2. PAM2803 datasheet says for C2: 6.8µF min., 10-22µF recommended.

So for the first build – to rule out any errors from possible lack of capacitance – I populated C2 and C3 and pushed in the highest values I had for 0805 (22µF, measured ~20µF) and 0603 (4.7µF).
In the next build I wouldn’t mind to use 10µF for C2 and either leave C3 empty or take a 1µF or 2.2µF.

I already consider to remove C3 from the board to get some space if needed (LVP resistors perhaps), but I tend to implement LVP in 17mm boards first for further development and only when we have a solution there I will start to see what can be put into 15mm.

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Gunga wrote:
Oh sorry. Desperate for a good driver and jumping the gun. Smile
Smile
In OP I redubbed “released” to “shared”.
Just to avoid a misunderstanding that we have finished, tested, evaluated, ready-for-industrial-production boards.
We haven’t.
Just some boards I cobbled together for personal use and did not mind to share.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

fixed it
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HarleyQuin wrote:
Other ideas for a lower Low? Suggestions welcome.
It is just proof of concept code but you could try this:

 

#define F_CPU 4800000UL 
#include <avr/io.h>
#include <util/delay.h>

#define FET_PIN PORTB1

int main(void)
{
   while( 1==1 )
   {
       /* Empty the gate. */
       DDRB |= (1 << FET_PIN);
       _delay_ms( 1 );
       DDRB &= ~(1 << FET_PIN);

       for( uint16_t i = 0; i < 150; ++i )
       {
           /* Charge a bit. */
           PORTB |= (1 << FET_PIN);
           PORTB &= ~(1 << FET_PIN);
           _delay_ms( 200 );
       }
   }
}

 

It's a slow ramp on the FET gate charge which repeats forever. It goes from 'invisible' to 'a bit too bright to look at directly' on a BLF-A6 FET+1 driver. From the spec sheet, your small FET should charge much more quickly as the gate charge is about 1/8th. You can avoid the higher end by reducing the '150' loop counter. Slow down the ramp by increasing the '200' delay. If the steps are too large, a CPU frequency of 9.6 MHz instead of 4.8 MHz should help. And if it's still too bright, PWM could be done with some work. Oh and keep an eye on the FET if you run this, it could get fairly hot at moderate output.

 

How this would behave with a depleting cell depends on the output voltage of the boost circuit at near zero load (ie. I don't have a clue). On a li-ion setup I can compensate for the lower voltage with more charge. Could perhaps do something similar here if there was a voltage readout, which I understand would be tricky to fit in there. The other "fix" is to just have more modes.

 

Also, I've never tried this but the weird code could be probably replaced with regular PWM and a resistor of the right value between the PWM pin and the FET gate. I'm not sure about the component sizing (not my domain and seems very tight) but ideally, I think you could keep pin 6 as it is and connect pin 5 to the FET gate via through a resistor, or the other way around. That would make one PWM channel pulse the FET full on for the high modes and the other give the FET only partial charge for the low modes. It would be much easier to adapt current dual-PWM firmware that way. A simple matter of disabling output of the unused PWM pin for any given mode.

 

A completely different option would be to keep the "full on" short FET pulse but with lower frequency to reduce the PWM duty cycle. You can get N times lower output by decreasing PWM frequency by a factor of N. But it will become ugly at some point. It is also somewhat annoying to code, like what I posted above.

 

Anyway, this long rambling post is just to say there are options so don't worry too much about current lack of a very low mode. I hope I didn't write anything too crazy Smile

ImA4Wheelr
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Ordered some of each board. Hopefully, I will have the time to join in on the testing. Has anyone identified a low cost source for the inductors in the US?

mattlward
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I just ordered my allotment of boards from OshPark and forgot to order the 17mm set of these. Sad Will have to get a set on the next order, wanted to test in a P60! These look very interesting.

Good work!

EDC rotation:
Convoy S2+, 6*7135, XM-L2 3D, 10 degree TIR, PilotDog lighted tailcap.
Convoy S2+, H17F, XM-L2 4C, lighted tailcap
Zebralight SC52w-L2
Olight S1A
Olight S1R

Rufusbduck
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There seem to be a lot of inductors on eBay but the nice short ones HQ used might be only mouser/Digikey.

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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I just don’t have the time right now to read all the separate threads on this topic. Mostly, I just want to know what range of smd footprints will work with these boards.

Regarding inductance rating. I see recommended above 4.7uH. In another thread there is a pic that says it has a 2.2yH, Coilcraft XFL4020 used. Was yH a typo? Sorry for the newbie questions but I haven’t spent any quality time with inductors and don’t have time right now to do so. I only understand what they do at a high level.

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guys, thats me: LOL

.

@fixed it
That sounds promising.
I admit I understood only every second word of what you said, but i’ll dig into it.
I’m no firmware guy but I usually can adapt what others come up with.

.

@ImA4Wheelr
Here in EU these Coilcraft inductors even increased in price about 70% in the last 12 months. They were expensive back then, they need to be weighed in gold by now.

Any other inductor with the µH-specs and size should do, I tried several (look at my 3rd pic in post#4).
The other (non-Coilcraft 2.2µH) inductors have mostly higher DC-resistance and thus are less efficient, like, losing some 5-10% output in 1AA and (some) runtime in 2AA.
All inductors I tested (same board, swapped inductors, same cell, measured output current; very humble and unprecise testing scenario) did work on the Nanjg110. Only difference I experienced was efficiency.

Datasheet does not say above 4.7µH, it says minimum 2.2µH, 4.7µH recommended. All commercial driver of this kind I recollect have 2.2µH inductors. I tried 4.7µH and the only difference was that they were less efficient at similar size (as they have by design a higher resistance than the 2.2µH). 4.7µH might/will have advantage in other terms (saturation?) but i wouldn’t know anything about it. I’ll stick with 2.2µH. You can take the inductor from the FT-driver for starters.

y makes for µ on a keyboard without a µ.

.

@mattlward
Allow for 12-15 hours and you get another 17mm driver board to choose from.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

mattlward
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Hey HQ, thanks for the update… I will wait a day or 2. So, the build is a parts steal right? Any idea what kind of output might be there?

EDC rotation:
Convoy S2+, 6*7135, XM-L2 3D, 10 degree TIR, PilotDog lighted tailcap.
Convoy S2+, H17F, XM-L2 4C, lighted tailcap
Zebralight SC52w-L2
Olight S1A
Olight S1R

HarleyQuin
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ImA4Wheelr wrote:
Mostly, I just want to know what range of smd footprints will work with there boards.
Good point.
I added the SMD part sizes in the HQB15 v3 post. All HQB15 (v1/v2/v3) have the same parts.
In the HQB17 v1 post the footprints are stated. Notable difference is the larger inductor.

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mattlward wrote:
Hey HQ, thanks for the update… I will wait a day or 2. So, the build is a parts steal right? Any idea what kind of output might be there?
Yep, oncoming HQB17B is specifically meant as the simplest possible part swapping build (keeping fingers crossed that C2 will be sufficient).
Output should be in the 750mA range with 2AA. Very well within the spec of the PAM2803. Output depends on R1 (Sense Resistor) and the FT driver has R1 = 0.120 Ohm (“R120”), could change with any production batch, as always.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

fixed it
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HarleyQuin wrote:

That sounds promising.
I admit I understood only every second word of what you said, but i’ll dig into it.
I’m no firmware guy but I usually can adapt what others come up with.
Maybe I should have summarized:
- The code I posted is to test the behavior of the FET with a partially charged gate. Quick & dirty way to see low output. Don’t leave it running too bright too long.
- Plan B: It can be integrated into other firmware for low modes, with some difficulty.
- Plan A: The hardware can be changed a little to get similar low modes with slightly modified existing attiny13a firmware. The resistor value can be approximately worked out from behavior of the code I posted.
- Plan C: Use lower PWM frequency. Also complex but definitely possible and with no hardware changes. Has risk of visible PWM eventually. Might eat up valuable firmware space.

The major unknown is how much the results of A & B will depend on part variations. I’ve not done enough testing to have any clue. It could be that each driver must be flashed with different settings to get the same output. I think that would be annoying but still better than no low modes at all.

DavidEF
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mattlward wrote:
Hey HQ, thanks for the update… I will wait a day or 2. So, the build is a parts steal right? Any idea what kind of output might be there?

Yeah, some clarity about output expectations for 1xAA or 2xAA would be nice. Also, I don’t know anything at all about driver development. Does this need a custom firmware written for it, or do (any/all) the already available Tiny13 firmwares work? I’ve been trying to follow along, but I’m way over my head.

Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone.
-Ayn Rand

calipsoii
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fixed it wrote:
It is just proof of concept code but you could try this:

 

That is a very interesting approach, fixed it, thanks for posting! Most spend their time trying to bypass triode, not linger in it. Like you said, it'd be interesting to test what kind of dissipation occurs if you drive it that way and whether the trade-off in efficiency is worth it.

Rufusbduck
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This isn’t about high power. Output remains the same and is limited by the power handling ability of the boost ic to ~1A Max or lower by choice of sense resistor. What’s new is the addition of the Attiny 13A. This opens all the AA and 2xAA cheapo and not so cheapo lights up to mods without annoying strobe modes or with modes of choice. Non muggle modes for muggle lights.

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

Scott

ImA4Wheelr
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Thanks for the responses HQ. I’ll raid my parts bins tonight and then order what I need.

HarleyQuin
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HQB17B v1

17.6mm boost driver board
designed to source as many parts as possible from the FastTech boost driver

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EDIT: More capacity really is needed: see post #30
Either you need to add a capacitor at C3 or swap for a larger C2 (like 22µF)

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Oshpark Link

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Parts size
(more on parts and values see partlist overview in post#2)

Switch: PAM2803, SOT-23-6
L1: max 4.3×4.3mm
D1: DO214AA
C1: 0805
C2: 0805
C3: 0603 (optional)
R1: 0805
R2: 0603
R3: 0603
MCU: ATTiny13A-SSU, 8S1
OTC: 0603 (optional)
FET: N-Channel, SOT-23-3

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The highlighted parts are those from the FT-driver, just add an ATtiny, C3 and – if needed – an OTC.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

Rufusbduck
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Thanks! That’s a very helpful highlight.

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

Scott

HarleyQuin
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It’s time for some field testing.
I just built a HQB15 v2 and installed it in a Sipik SK68 clone.

First memorable result: A swap of the FT driver will need additional capacitance (higher C2 or additional C3).
I did at first a straight transfer of only the FT parts and got only initial flickering. Like: strobe for half a second. Same after every mode change. I changed between different driver frequencies, still just flickering.
The FT driver had 10µF as C2 (10.7µF according to DMM, I tested it after harvesting the part). Added a 10µF 0603 (tested 7.8µF) as C3 and – voila – the light stays bright in every mode.

R1 is 0.120 Ohm (R120), no ‘overclocking’ for now.

Flashed is the already mentioned adapted MiniDrv with 3 modes (PWM 1,8,255), with on-time memory (no OTC).

I started with 4.7kHz (9.6MHz, fuse 6a (divider:8), fastPWM) and now flashed to 38kHz (9.6MHz, fuse 7a (divider:1), fastPWM). Both work, 4.7 is whining considerably and has higher low, 38kHz is silent and slightly better at PWM1.

Let’s see how it handles some heavy use. Pics later.

Edit:
Of course I swapped for a BAT60A before installing into the SK68, as the original diode was only attached by wire.

Oshpark Boards:
Boost: HQ 15mm/17mm programmable boost driver with ATtiny13A
46mm Triple-Channel: BLF SRK FET v3 . 17mm Linear: HQ10D / HQ4D / HQ4S . Contact Boards: 22/24/26mm

Rufusbduck
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Good to know, thanks. Still waiting on the boards.

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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