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Thread: Desperatly looking for driver (updated kennan driver?)

  1. #121
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    I'm currently running three XR-Es at 700mA on a 14.8V pack. Haven't calculated efficiency yet, but the driver runs very cold.

    I didnt change the R1 as I didnt have any low value resistors.

    Instead I put a 100k resistor from output to R2 as shown here: http://www.candlepowerforums.com/vb/...8&postcount=85
    I kept the R2

    This gives me a 700mA output.

  2. #122
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    I guess the value needed for that approach depends on the value of R2 (which does change between one board revision and another) as well as the number of LEDs driven, so it would either need calculation or experimentation.

  3. #123
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Yes, you are right, I didn't think of that. R2 is 1k on my board.
    One way is to adjust the current to whatever you want with a potentiometer, then measure the resistance in the potentiometer and switch the potentiometer for a fixed resistor.

  4. #124
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    I want to use two boards in parallel. Is it possible to to wire the 2:nd as slave to the first one, so that when you adjust the output from the first one, you also adjust the 2:nd?

    Would it work if I remove the R2 on the 2:nd board and wire the FB pin to FB on the first one?

  5. #125
    Flashaholic* kosPap's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    hi all! In this post in another thread I have added measurements of 2 versions of this driver.

    Enjoy, Kostas

  6. #126

    Default Re: Desperatly looking for driver (updated kennan driver?)

    another way to mod R1 if you don't have these low value resistors is of course to replace R1 with 1 ohm resistors in parallel. i'm using two in parallel to get .5 ohms which runs 3 leds in series at 330ma. see parallel resistor calculators on the web or for these just simply 1/number of resistors so 4 would be .250 which i think the original kennan had. i think it's easier to do the dimmer mod and then if you want swap the pot for the resistor of your choice as gillestugan mentioned but this is another method.

  7. #127

    Default Re: Desperatly looking for driver (updated kennan driver?)

    apologies for resurrecting an old thread but I came across this discussion when trying to find ideas for drivers and the mention of the PT4105 got me curious if dealextreme did any equivelent.

    Well, after a bit of poking around I can say that that the DX SKU07425 is based on the PT4105.
    I've buzzed out the board and it is identical to the data sheet example circuit except for the following-
    1) It has two 0.5R resistors in parallel for the sense resistor (giving 0.25R and 800mA drive rather than the 1A quoted by DX....)
    2) it has a 10k resistor from the sense to the feedback pin
    3) it has a piggy back microcontroller to give the 5 modes.

    As the basic circuit is as per the data sheet I can't see why it won't work to 18V rather than the 8.4V quoted. The only possible problem is the piggyback board which I haven't checked thoroughly. However, there is 5V going to the IC so I think it is regulated so the only question is whether the regulator will cope with 18V. Most will....
    I've taken it up to 12V when driving a single Q5 and it still works fine

    Hopefully that might be of help to someone?

    Toby

  8. #128
    Enlightened
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    Sigh Re: Desperatly looking for driver (updated kennan driver?)

    I'm new of this forum, so first, hello to everybody!
    I'm posting here because I have a problem with this driver. I've bought it from KD, but I've got a new board, different from all the previous here and also from the one shown on the KD site, so I don't know where to solder the led wires.
    This is the image:

    I'm quite sure the "+" should go under the inductor, where there is the "+", but should I solder the "- " (looking at this image) over the R1, under the R1, or elsewhere?
    Thank you all in advance!

    P.S. I don't want to fry this board because I've waited over a month and I have only one (the one I have to use...).

  9. #129

    Default Re: Desperatly looking for driver (updated kennan driver?)

    The AX 2002 are simular to the PT4105 (used on previous model) in the way it operates, but the pinout is different. The AX2002 is a bit more powerfull and can handle abit higher input voltage. (Can handle abit higher swithcing current and up to 23V input voltage compared to 18V for the PT4105.) I can't see the R1-label you are reffering to, but I guess you are talking about the R220-resistor. The "-" should be conected to witch ever side of the R220-resistor that is not directly connected to "-" for the board. From your picture it seems like that is the "south-end".


    space

  10. #130
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    duplicate post - removed

  11. #131
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Data sheet can be found here.
    Would it be possible to regulate output by using resistors as voltage dividers for the FB bin in the same way as on the PT4150?

    Will also be interesting to see what efficiency you get and how high output it can manage. (2A in the data sheet, but that is just the AX2002, not the rest of the components.)

  12. #132
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    The AX2002 datasheet does mention pins 5&6 are a thermal path to the internal die, so it might be possible to arrange for some extra heat dissipation for high current usage.

  13. #133
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Thank you very much, I've tried to do that and, from a very quick test on a single 18650 (but I'll use a 6v lead-acid) it looks to be working correctly.
    P.S. Thank you also for all the other useful information on this forum!

  14. #134

    Default Re: Desperatly looking for driver (updated kennan driver?)

    Hello from Frenchees!!!!

    I have a problem with my KD rgular!

    For 3 regulars i have 800mA : Good!

    For 6 regulars i have 400mA : No good! But why i have 400mA?

    My last regular do : Psssssssssssshit!
    Last edited by Spykooo; 01-21-2009 at 02:02 PM.

  15. #135
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Are all the drivers the same?
    Do they all have an 'R220' or 'R270'?

    What input voltage are you using?
    How many LEDs are you driving, and what is the total Vf for your LEDs?

  16. #136

    Default Re: Desperatly looking for driver (updated kennan driver?)

    Quote Originally Posted by uk_caver View Post
    Are all the drivers the same?
    Yes.

    Do they all have an 'R220' or 'R270'?
    Normaly R220.

    What input voltage are you using?
    Alimentation made in home : 9,6 volts.

    How many LEDs are you driving, and what is the total Vf for your LEDs?
    One P4 rank U.
    Thanks!

  17. #137
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    I received the AX2002 version today and will do some efficiency measurements.

    Does anyone have a request for a specific condition? (Vin,Vout,Iout)

  18. #138
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Have done some testing now and I like it! It is very tough. As you can see in the graph I was able to push it to 2,5A. Then it was shutdown by the thermal protection. When I turned it on again it worked like before. This happened many times during the 2A+ tests, until I put an extra heatsink on it. It wasn't really stable over 2. Had it on 2.2A for 5 min, but then it got too hot and shut down.

    The test setup:
    Old computer PSU
    Mulimeters (Vin, Vout,Iin,Iout)
    8A rectifier diodes as load. (didn't want to risk my MC-E)
    Modded driver with dimming, lower R2 and a small heatsink soldered to pin 5 and 6 as suggested bu uk_caver

    As you can see there are some variations, this can be because of:
    I used the 20A socket on the multimeters and they are far from accurate, but both mulimeters are axectly the same and gives the same value of a current, so it shouldn't influence efficiency calculation too much.
    The diodes got hot and VF changed slightly, this is of course measured and in calculation.
    The dimming method used is not very temperature stable.
    -A real amateur test




    Here are some pictures of the board:
    To do the dimming mod you have to cut one of the tracks on the board. (see picture)
    Then solder A potentiometer and a resistor as shown in picture.

    If you want higher output than 1A you need to change R2 to a lower value. Look in the data sheet for resistor values.






    Heatsink with ugly soldering, sorry
    Last edited by gillestugan; 03-03-2009 at 08:40 AM.

  19. #139

    Default Re: Desperatly looking for driver (updated kennan driver?)

    Well i have looked to all ends to find a good driver for the SSC P7 and cant, so i found a IC that will do a Max of 3A with 2.5V-18V in and a 89% efficiency from .25A to 3A at 5Vin and 3.3Vout. per paper calculations, still not tested. All that and you only have to use 8 to 12 or so parts if you want to use the ICs over-current protection, and short circuit protection. im hoping to have a prototype working soon

  20. #140
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Nice work, gillestugan.

    I may order a few more Kennans myself. I've been building a few smart chargers for 3.6V NiMH packs using the PT4015 Kennans running at 750mA, but it would be nice to be able to make some faster (~1.5A) chargers.

    It looks like the soldering is to pins 7&8 (2xVss), rather than 5&6.

  21. #141
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Quote Originally Posted by uk_caver View Post
    It looks like the soldering is to pins 7&8 (2xVss), rather than 5&6.
    You're right! Haha, maybe I should do one more test with the heatsink connected to the right pins. It did get pretty hot, but I assume most of the heat came from the top of the chip. Thanks

  22. #142
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    I guess heatsinking the chip top probably *is* doing a lot of the work - the pin 5&6 thing is most applicable to a board designer who has onboard copper to use, but who won't want to bother with glue-on heatsinks.

    Did you measure the current with the stock R220 for R2? Is it the expected ~1.14A, or something else?

    I just ordered 5 boards - here's hoping they come with AX2002s

  23. #143
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Where are these on KD's site? I did a search for kennan but didn't come up with anything. I know I've seen them before but I can't find them now.

  24. #144
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Spencer:
    They used to name their items and this one got the name "kennan". Now they only use numbers. Boring but more practical. You can find it here.

    uk_caver:
    Whe I first hooked it up it was exactly 1,00A (!). Then it varied between 0,97 and 1,03 depending on input voltage and probably also temperature.

  25. #145
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Hello Im new to this board.

    I just received a few drivers of the AX2002 version and I would like to use the dimming mod for running one Cree R2 LED between 100mA and 500mA. Im going to cut one of the tracks on the board as shown in the picture. The problem is that I dont know where to connect the potentiometer and the resistor that are apparently needed.
    Then solder A potentiometer and a resistor as shown in picture.
    Maybe Im just overlooking something but I cant see an additional potentiometer on both pictures. The only thing I see is a resistor hiding behind the copper heatsink. Where do I have to solder both parts and what resistance do they have to have?

    Thank you very much in advance!

    Olaf

  26. #146
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    There was apparently something wrong at imageshack and the picture. I have now rehosted the image and it should work fine.

    Resistor values cant be calculated without knowing the exact Vf of your led at those levels.

    You can set maximum to 500 mA either by replacing R2 with a higher value (calculated with the formula in the datasheet) or use the right resistor values in the dimming mod.

    Easiest to do it is to measure the resistance on the potentiometer when you have 500mA. Then put a fixed resistor with the same value in series with the potentiometer and you will have a new maximum at 500mA.

    You can then measure the potentiometer resistance at 100mA and replace the potentiometer with one that has the measured value. You will then have a range between 100mA and 500mA

    An alternative is to use a zener diode as voltage reference. Any zener with lower value than battery voltage will do. If so I can calculate resistor values for you.

    you will then need one zener diode, two fixed resistors and one potentiometer. The dimming will then not be dependent on output voltage and will work the same regardless of how many leds you put i series on the output. (the board can easily handle 6 in series)

  27. #147
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Thank you very much for the information! I guess Ill go with the right resistor values in the dimming mod for now and do a little testing on how well it is working in terms of efficiency with different battery solutions over the voltage drop of the cells.
    Again, thank you very much for your help.

    Olaf

  28. #148
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    My AX2002 boards just arrived, and they look like the ones posted above.

    I was wondering if anyone knew what was happening with the COMP pin (pin 3)
    On the datasheets, it's shown as having an 11K res and 0.1uF cap in parallel to ground fotr a single-diode load (and 20K/0.1uF for 3-dioide loads) but on the KD boards, it has a 100K res and some capacitor to ground, but also a diode and series 4K7 res leading to inductor +ve (pins 5&6)

    That diode/resistor combination doesn't seem to be shown on the datasheets, but I'm assuming that it's there to try and automatically adjust the average resistance from the COMP pin to ground based on the duty cycle.

    Would anyone have any idea if I'd be better off removing the diode/resistor and replacing the 100K res with a smaller one, if I know what my input/output voltages are going to be?

  29. #149
    Flashaholic gillestugan's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Quote Originally Posted by uk_caver View Post
    That diode/resistor combination doesn't seem to be shown on the datasheets
    Are we looking at the same datasheet?

    Isn't it the diode and resistor in the circle directly under the chip in the datasheet schematics? marked "option"
    It says "The option circuit for compensation is connecting R4 and a
    4148 diode to Vout. In order to protect short circuit and thermal shutdown release for LED." It probably takes some power, but I have not measured voltage over the resistor, so I dont know how much power would be saved from removing it. I have tried both short circuit and thermal overload, and those function very well

    I also dont see a 11k resistor anywhere in the datasheet. Only 100k. Same as used on the board.
    It says "100KΩ for all condition" so I assume there is nothing to gain by changing it.

  30. #150
    Flashaholic* uk_caver's Avatar
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    Default Re: Desperatly looking for driver (updated kennan driver?)

    Quote Originally Posted by gillestugan View Post
    Are we looking at the same datasheet?
    It seems not - I was looking at the Axelite datasheet I found when the AX2002 was first mentioned in posts 128/129.
    It's marked "Rev 1.0 Oct 26 2007"

    It doesn't show the resistor+diode in the any diagrams, and all it says about the COMP pin is
    Compensation
    The COMP pin connects C3 and R3, C3 use 0.1uF in all condition. R3 use 11kΩ at
    Duty on <60%, and use 20kΩ at Duty on above 60%.
    Quote Originally Posted by gillestugan View Post
    I also dont see a 11k resistor anywhere in the datasheet. Only 100k. Same as used on the board.
    It says "100KΩ for all condition" so I assume there is nothing to gain by changing it.
    That certainly squares with the KD circuit board. Obviously they must have changed things somewhat between v1.0 and the v1.2 you linked to (which I just downloaded).

    That also explains the capacitor to ground from the enable pin on the KD board - on the v1.0 datasheet, it wasn't there - just the 100K pullup.

    Thanks for clearing that up.

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