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Astral Driver - Boost, Buck, & Sepic

astralist

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There is actually some limitation about this Omnidrive:
when boosting, it can only outputs something between 100-450mA (should be 72.5mA - 1.1A as per design on paper)
when bucking, it can only outputs something between 450-850mA (should be 72.5mA - 3A as per design on paper)
outside that range, the driver went lockout because of internal safety mechanism :undecided:
To set the current, you need to turn the potentiometer while the driver is turned off

The IC is not giving its advertised performance, but that understandable since i actually forced the layout to save some space while compromising some electrical law.


And BTW, here is the generic boost driver, the one you usually saw on ebay/aliexpress which is voltage regulator, but my version is a true current regulator :D
I didn't realize soldering *only* 45 boards is so time consuming LOL.










And here is the test result:

Method:
using 4.2V freshly charged battery source,
using a series of diode to simulate laser diode,
current measured across 1Ω resistor.

Generic L:
Core IC: FP6291
@108mA, 6.5Vo



Generic H:
Core IC: MT3608
@min pot (138.5mA), 5.99Vo


@198mA, 6.92Vo



I couldn't find the max current output as it keeps blowing away because of overheat :crackup:
Output "open" can also kill the drivers (for the H version)



My conclusion:
Although it can't really drives a high current diode, all these new driver will be able to safely drive a laser diode with low current.

Omnidrive: 50 left, $19.9 each
Generic H: 18+ left, $14.9 each
Generic L: 18+ left, $14.9 each



Please note that the Generic H/L boost driver is currently experimental, the behavior of each driver is different, maybe because of possibility of counterfeit IC??? :can:
 
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paul1598419

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I do need a cheap boost driver for all these Sharp diodes. Maximum current would be 350 mA, but most likely would be closer to 300 mA. I'm a bit nervous about these generic H/L boost drivers as I don't want to lose a diode to a poor design, counterfeit ICs or other problems.
 

astralist

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Indeed.. Im currently looking for a reseller of genuine IC, because i can't even find it on digkey or other big place..

But as per my test, it is proven that it can be configured as a current regulator, contrary to the readily available version which is a voltage regulator.
I'm designing the Generic boost because i am in need of a current regulator to drive small current high Vf diode like PLT 450B in a pen host with button. :D

But I'll just go with the Omni for my laser diode with a high Vf and high current right now.
I'll let you guys know if there are updates about this Generic boost. Or even a round version :beer:
 

astralist

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Some update after I went missing lol:

After i tested it thoroughly, I came found something interesting about Generic Boost driver,
It's the switching diode that couldn't hold up the >500mA current, which is pretty interesting since i'm using a 2amp diode (PMEG2020).
Some of the IC itself is actually blown up or instantly dead but that's only because i left the output open and/or mistakenly using two cell to power up the IC.
Also, at some output current which produces the output voltage of lower than the input current, the IC might die as well.
So i decided to include all the future drivers with a free diode to be soldered in series with the V+ of the driver, it's optional.

some case would be:
  1. Running the driver with 4.2Vin to drives 1.8A output of, let say NUBM44 diode, which produce 4.0Vout. This resulted in unregulated driver. The workaround is by using diode (with Vf of ~0.7) in series with V+ of driver so that the input is always reduced by 0.7V. Also, it can act as a battery reverse protection
  2. Running the driver with 4.2Vin to drives 100mA output of, let say a low power single mode diode (488nm 495nm 510nm, etc), which produce 6.5Vout. This will be a fully regulated output since the output voltage is higher than input voltage, hence you won't need any input diode in series with the driver.

Therefore the generic driver is improved, now it has a size of 9x12mm
and will be a direct replacement for those PicoDrive (and sold as PicoDrive) that i never openly sells
 

paul1598419

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Is there a price change on these new drivers? I'm trying to remember, but it was ~$15 each, right? I'm sure I will need some of these for future builds, but is there anything wrong with the old PicoDrive? I found them to be fine in my testing and plan a build with one.
 

astralist

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No price change paul it's $14.9 each from when it were a "Generic boost", that's why i produce 200 units to get a bulk discount of pcb printing and pcb assembly.


The old PicoDrive has been used by jnrpop and he drives 477nm diode without problem,
First, the IC is actually doesn't have internal soft start, so on a higher current output, it sometimes creates an overshoot. Ever since I killed my 16x diode, i never openly sells it to anyone, just for someone really needed it and stating all the limitation.
Secondly, the internal switch current is only 1.7A, which is pretty low, compared to the new PicoDrive with a 4A internal switch current.
Also, on the old PicoDrive, i'm wrong about the calculation of the inductor and capacitor, so the frequency of right half plane zero got me good.
And the last reason is the economical reason, the old PicoDrive costs more than Generic Boost :D


maybe jnrpop and lifetime17 could share their experience with this old Pico.
 

paul1598419

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That's fine, Pradipta. Just didn't want to destroy a 495nm laser diode using it. I have it set for 300 mA. I think the Vf at that current is ~6.3 volts or so. If it is okay at that current, then no problem.
 

astralist

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First post updated!

Here is the layout of the new driver that are being designed and fabricated:

New PicoDrive (Successor of PicoDrive and Generic Boost)


New SuperDrive LV (Although this is a boost, it can also do a step down, not like the old SuperDrive LV)


SuperDrive V (This is basically a Generic "everyday" buck, max Iout = 5A, priced at $16.9/pc)



I'll add information about OmniDrive and Generic Boost on the first post later!
Any question just lemme know :beer:
 
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paul1598419

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Thanks for that updated information. I eagerly look forward to the next post of new driver information. :thanks:
 

paul1598419

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I could use a couple for my stock as you never know when Sharp might come out with a new wavelength. What is to current range for these again?
 

astralist

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The driver should be able to outputs 30mA-2000mA (TBD, per design on paper, depends on Vout)

e.g:
Driving a 4.8Vf diode is ok with 2000mA output current
But driving 7Vf diode, the max current might not reach 2000mA
 




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