Need specific drivers

will be bigger..

Like I posted in the "Dear Dr. Lava" thread, these are some DC boosting ICs with
a voltage and current range around what our diodes need.

LM5118
LM2577/-8
LM2621
MAX668
MAX862
MAX1760
LT1310
SC4501

Most of these require only a couple of resistors and caps around their pins to make
a complete boost circuit. Some are not cheap though (10$).
I'd love to have one each and do my experiments with them....

There has to be a way.

Uhm .....

LM2621: never tried it, cause looking at the datasheet, the circuit needed for the FB input is too much complex for be directly substitute with a low value resistor.

LM2577: i discarded it when i seen on the datasheet that it still require a FB of 1.2V (high FB voltage = high power dissipation on the RSENSE), and anyway the current is limited to 800mA

LM5118: very complex, it require 2 external mosfets for work in buck/boost mode, and don't work under 3V

MAX668: Not tried it, cause the min Vin of 3V ..... tried the MAX669, instead ..... it work until some point, then tend to become unstable ..... probably cause for low voltages you need to use it in bootstrapped configuration, that take the power supply from the output, and sometimes it go in self-oscillation (i cooked a test load, just imagine a LD )

MAX862: never heard about it ..... are you sure you don't mean MAX6825 ? ..... if is the 6825, can be, it's a buck/boost ..... need to get some samples (if Maxim is not tired about all my past samples requests )

MAX1760: not tried it, but looking at the datasheet, is not too much promising ..... max current 800mA, max Vout 5.5V, and the FB regulation depend from the OUT pin, so you probably cannot directly connect it to a RSENSE in serie with the LD (that anyway is still 1.24V, too high for good efficence using only a RSENSE) ..... also, the ISET pin does not regulate the load current (it was too good, otherwise ), but only the coil current.

LT1310: promising, but still high FB voltage, and need compensation (a little bit more complex circuitry)

SC4501: same as before.

I know i'm playing "devil's advocate", here, but designing a constant current boost driver, must be took in considerations a lot of parameters, if you want to get a working driver, at the end ..... and, trust me, i'm one of the first ones, that want to find a good and cheap alternative

New idea, can I use this driver 1W 445nm laser diode driver / 200mW 405nm laser diode driver [OL-445-D] - $14.99 : Welcome to O-Like.com, Your source for laser products and change the resistor to fit my specific needs?

If so can someone teach me how

BH - those drivers (and similar clones) are not great. you'd be better with an NJG18

HIMNL9 - why not just use two 63010s in parallel on a single PCB?

With an njg18 what is the settable current range? I've never used them because they seem a little hard to use.

rhd said:

BH - those drivers (and similar clones) are not great. you'd be better with an NJG18

HIMNL9 - why not just use two 63010s in parallel on a single PCB?

Click to expand...

You should ask stevie, he gets higher powers out of them. I just use them at stock 1A or so.

I'll give him a call.

Do you know if they can hit lower currents?

bhwollen, I don't think the NANJG-18 (njg-18) circuit opperates properly with low Vf diodes like 650nm. Some people on the flashlight forums have mentioned it can go into direct drive mode if the input voltage is above the configured output voltage. (Remember this is a voltage, not current regulator). So just keep that in mind.

HIMNL9, have you looked at any of the Seiko, Vishay, Micrel switching regulators?

I'm really keen on getting an open source project going. I'm willing to do any schematic capture and PCB layout. I've got contacts at PCB manufacturing companies and automated PCB populating/reflow lines. But if we stick to non-bga chips reflow at home can be done. It won't be cheap to have smaller quantities of boards assembled professionally, but if it needs to be done I'm willing to spend some money on this.

I would like to get a 1.8A or 2A single cell Li-ion boost converter for high Vf (~5V) 445nm diodes going first.

@ rhd: cause they was not designed for work in parallel ..... the fact that they work, is a "plus", not a normal thing (and also, you still need to double the components, doubling also the required space ..... much more easy to use drivers with external mosfets, for this purpose)

@ MegaTesla: well, i may probably have turned all those manufacturers (and also others ) very tired, asking for samples here and there and everywhere ..... but very few of the ICs that i have tested til now, have worked in current mode, and also less of them was stable and simple at the same time ..... i'm still testing, but not too much news, from ICs manufacturers, in this specific field ..... til now, at least .....

HIMNL9,

The MAX682 is a 3.3V to 5V 'charge pump' booster with a fixed output current 0f 250mA. MAX682 pdf, MAX682 description, MAX682 datasheets, MAX682 view ::: ALLDATASHEET :::

Pretty limited in application, other models 683 & 684 offer fixed output currents of 100 & 50 mA's respectively.

I posted this in an off-topic thread, but based on a post in this thread, it seems to be appropriate here, too:

Hi guys! Wow, I'm sorry to see the hate has gotten a little thick around here, and it appears that some people, even a business owner might be trying to take advantage of it as an excuse to copy designs. wow!

The fact is I've had to take a break from selling these for the last month or two because finishing my degree took precedence. I apologize for the delays/inconvenience/laserache that has caused some of you, thank you for your thoughts. I'm happy to tell you that that is over and done with now, things are rolling, and I have a LOT of PMs to go through

The drivers are being made right now and I expect to be able to start sending out more of the V5's in about 15 days. Not only that, but a few people have signed up to be distributors, and these people are a lot better with communications on here than I have been able to be, so that is an additional bonus.

I remember when I made the first buck/boost laser driver on this board, back when it was considered a hobby for most people, a fun passtime. People responded with great enthusiasm to the extra capability such a thing provided to the hobby. Fast forward to this year, and it appears lasers have become quite a bit more than a hobby to a lot of people, to the point where they would threaten to undertake ethically questionable practices to 'feed the need'. I think that no matter what stories are made up, it is important to maintain ones ethics like many have in fact done on this board.



All that said, lasers and the construction of them are a very enjoyable hobby and I'm working to improve driver availability to meet the expectations of members through helpful members like FlaminPyro, who will most likely become a distributor and contact for these drivers.

Also, I will go through every single PM and respond as appropriate to your questions as soon as possible.

If you have a question about a driver, PM, or anything else specific to you, please either be patient if you have PMed or PM me and I WILL get back to you.

Best wishes to all!

Any chance you'll be able to iterate a new version (V6?) capable of higher current on a 445 (negating the necessity of purchasing 2x to parallel for 1.5A builds, etc) ?

Or perhaps a lower price-point?

I agree with rhd. 1.5A just isn't enough anymore.

I'm glad the flex drives will be back soon! :yh:

Also, congratulations on getting your degree! I assume you were getting done with your masters? Finishing your thesis must have been a big load off your shoulders.