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2xAA blue ray driver (fits in aixis)

woop

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I got my blueray going without killing it and soon got sick of it being effectively a "labby" because of all the batteries and large 311 driver. and i couldn't find a case big enough.
anyway, some of you might remember the thread on using a smps with the lm3410

this driver uses the same chip and parts, but it is just a straight 'boost' converter, it should boost anything from 2.5 - 4V to above 5V with programmable current regulation (with a resistor). current can be programmed to anything between 30mA to 500mA.
this means running a blue ray off 2 AA or AAA's or one lithium.

AND i managed to design a single sided pcb which is only 8mmx16.5mm, small enough to fit in the aixis module

here are some pics of one i put together tonight. i still need to drill some holes to mount the diode on the other side of the board, so it will fit in the module, and add the input cap, and solder the BR diode on. but as it is, it supplies 34mA at 5.15V (dummy load) from a li-ion battery
tomorrow i will finish the board and test it on a blueray
also attached eagle brd file

(edit: updated images)




also here is the schematic (see the datasheet for more examples and part recomendations)
R1 can be calculated by I=0.19/R1
 

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rog8811

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That looks very neat. I must try etching my own PCB's one of these days, I am still in veroboard land with my builds at the moment....
Thanks for sharing.

Regards rog8811
 

woop

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yeah, its not that hard to make these things.
all thats needed is a laser printer, transfer paper, cloths iron and etchant for making the pcb's
and a toaster oven and smd soldering paste for 're-flow' soldering (its the only way to solder a chip with no pins)
(can be done for under $40 if you already have the printer, iron and toaster oven)

the only disadvantage with this design is that the case of the diode is not at ground potential, because of feedback for the driver, so the module case can't touch a grounded housing
it would be easy to include a differential amp on the bottom layer, i will have to look into it, and maybe use a different switching chip to allow lower input voltage (like 1xAA).
 

IgorT

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Nice work woop!

So this is still a current regulated boost circuit, right?
 

woop

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IgorT said:
Nice work woop!

So this is still a current regulated boost circuit, right?
yup. i decided the sepec design was pointless for blue-ray's
and only one inductor allows it to be a lot smaller.
now i have used up all of my lm3410's.
 

IgorT

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woop said:
yup. i decided the sepec design was pointless for blue-ray's
and only one inductor allows it to be a lot smaller.
now i have used up all of my lm3410's.
If you only use one Li-PO, the diode voltage will always be higher than the battery voltage, so there really is no need for a sepic.

And since these are reader diodes, heatsinking is not really a problem, so the need for isolating them is not an issue. It's just great to finally have a simple and small current regulated boost circuit!


Thanks for sharing this woop!


Oh, and i don't think it is really necessary to make one that would work off a Ni-MH. Not when we can get Li-Ions in all the same shapes and sizes and more. And cheaper than a Ni-MH cell in my country at that!

But it wouldn't hurt i guess.. :)
 

IgorT

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Can you also post the schematic? Is it from the datasheet or did you design it yourself?

And post the pics for transfer please.. ;)
 

woop

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its basically 'Design Example 7' from the lm3410 datasheet. but without the flash control. lm3410 circuits are pretty straight forward. one improvement is to add a opamp for a grounded diode, would be necessary for a torch mod unless you can insulate the case from the body of the torch.
if you can find anywhere that sells these http://www.zetex.com/3.0/product_portfolio.asp?pno=ZXCT1009 they would be perfect

anyway i finished the circuit and its now supplying 34.5ma to my blueray diode :D works perfectly, and fits perfectly as well.
I did add a 0.3uF cap across the diode for extra filtering
I just wish the beam was thinner.

click for some more pics http://s197.photobucket.com/albums/aa189/yaywoop/blueraydriver/?albumview=grid

here is the board ready to print. its 600dpi and already flipped
 

IgorT

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I can get that Zetex chip.. I almost ordered it together with a zetex boost driver, before you came up with the LM3410 idea.

I don't remember exactly how much the ZXCT1009 current monitor costs, but i think it was the least of all the components. I'll check, and let you know. It would be useful for Blue Ray burners, but for a reader diode, you can still isolate the module from the host. Heatsinking is really not a problem here.


I'm gonna use this circuit on some >50mW 405nm diodes i have ordered. Thanks again Woop!
 

woop

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what voltage are those 405nm diodes? make sure the input voltage is less than the diode voltage
another thing you could do is have multiple diodes in series as long as the total diode voltage is around or under 8V
 

phenol

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as of the 6x burner diode voltage, at 110mA it is ~4.7V and decreasing as it heats up, so i had to use sepic config if i wanted to power it off 4xNiMH cells. 2 would have been not enough, 3-perfect, but since my charger only charges 2 or 4 at a time, i decided to go with 4. when fully charged, the voltage per cell is >1.4V
 

IgorT

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Ok, here are the ZXCT1009 prices:

£0.95 1+
£0.78 10+
£0.56 100+

This is in GBP, so it's not really cheap as you can see. But if you have a nice design in mind, i could order 10+ and send some to you.

On the other hand, Phenols mod to the LM3410 achieves the same thing, with a more common (and probably cheaper) component. Would a circuit with the zetex current monitor be simpler and use up less space than the op amp circuit?
 

woop

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phenol said:
as of the 6x burner diode voltage, at 110mA it is ~4.7V and decreasing as it heats up, so i had to use sepic config if i wanted to power it off 4xNiMH cells. 2 would have been not enough, 3-perfect, but since my charger only charges 2 or 4 at a time, i decided to go with 4. when fully charged, the voltage per cell is >1.4V
huh? are you talking about a blueray burner?
2 AA's should have worked, they would only need to supply around 250ma to drive this circuit at 110ma @ 4.7V
 

woop

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IgorT said:
Ok, here are the ZXCT1009 prices:

£0.95 1+
£0.78 10+
£0.56 100+

This is in GBP, so it's not really cheap as you can see. But if you have a nice design in mind, i could order 10+ and send some to you.

On the other hand, Phenols mod to the LM3410 achieves the same thing, with a more common (and probably cheaper) component. Would a circuit with the zetex current monitor be simpler and use up less space than the op amp circuit?
the main reason i mentioned the zetex component is because it is in a SOT23 package which is tiny, and it doesn't require any other components
or only one extra resistor
 

IgorT

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woop said:
what voltage are those 405nm diodes? make sure the input voltage is less than the diode voltage
Yeah, i have played with boost circuits a lot, so i know what happens if the input voltage is higher than the output is supposed to be. :)


The 405nm diodes i have in mind are not really Blue Rays, but have similiar Vf.

I'm talking about the X-BOX HD-DVD drives, which contain diodes capable of >100mW. Of course there is no way of telling how long they will last, so i think i'll drive two at ~50mW and one at 90mW or so.

I just hope i get the right batch. A newer version uses a less powerful diode.
 




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