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Astral Driver - Boost, Buck, & Sepic

astralist

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If the output voltage needs to be higher than the input, then I cannot use this to drive two volt IR diodes, correct?
The Omni could do a buck, it will be able to output 2V,
you need to set the current (turn the potentiometer) when the driver is turned off

also, the max current capability when bucking and boosting will be different.
The max input voltage would be 16V
 



astralist

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UPDATE:

from the assembly factory:
The driver just shipped to me using DHL

Estimated Delivery:
Friday, March 23, 2018
By End of Day

I hope my package is not entering a "red line" again just like the OmniDrive :(
 

paul1598419

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That is good news, astralist. Let me know when you have tested the ones you will send me and I will send you the $$. :thanks:
 

astralist

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UPDATE

I just tested the driver.

Method of test:
  1. Using 3.8V battery source
  2. Current measured across 1Ω resistor
  3. Voltage drop (Vf) simulated using multiple combination of standard rectifier diode
  4. Driver not heatsinked


Here is the test result:

Min current (potentiometer at most CCW position): 70mA @ 5.72Vf


Current set at 107mA @ 5.91Vf


Current set at 208mA @ 6.2Vf


Current set at 210mA @ 7.7Vf


Current set at 480mA @ 8.3Vf




Aaand, here is the current set at max potentiometer setting (potentiometer at most CW position)

Current output: ~1300mA @ 6.2Vf


Current output: ~1600mA @ 4.9Vf



Please note at max pot setting:
it looked like the driver outputting an overshoot, but it's not an overshoot!
it's because the driver gets hot easily and the current output declined rapidly as i tested the driver without heatsink.

Heatsink is mandatory if you are going to use this driver to drive a high power (current*voltage) output!!
 
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astralist

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High voltage test:

Vin: 12V
Vout: 32V
Iout: 0.6A
Result: Working and well regulated

Vin: 18V
Vout: 32V
Iout 1A
Result: Working and well regulated

For any string of laser diode producing Vf or Vout below Vin while Vin is "high enough", the IC will fried instantly.
Remember, this is a boost driver, therefore Vout below Vin meant you are violating the use of boost driver.
 

paul1598419

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I need five of your low current boost drivers ASAP. Will send a PM.
 

Alaskan

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Ordered 15 wish I had ordered 5 more.
 

paul1598419

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Thanks for shipping them out so quickly. I appreciate the tracking number. :yh:
 

astralist

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More high voltage test of PicoDrive:

Test method:
  • Using 4x Li-ion battery as input, totaling 16.6Vin
  • Vf simulated using long string of diode, plus some resistor
  • Current measured as a voltage across 1Ω resistor
  • Driver is NOT heatskinked

Current set: 211mA @ 27.7Vf, 16.6Vin



:beer:
 

paul1598419

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Pradipta, do you still have a Pico buck driver that can be used for low currents around 200 mA or so? Someone asked me about these and I didn't have an answer for them. Did you have a boost/buck driver that could work like this with two Li-ion batteries to output between 150 mA and 350 mA?
 

astralist

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The question is, 150-350mA at what Vf?

I have the omnidrive buck/boost, but the dynamic range of the current setting is not quite good, when bucking it could output something between 400mA-800mA, while only outputting 120mA-400mA when boosting.

It seems i need to create more reliable buck/boost driver in future..
 

paul1598419

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Yeah, I need one for a Vf of up to 7.0 volts and a current between 100 mA and 400 mA. I have some new old stock adjustable bucks that fit this bill from Lazeerer. I would love to see another driver like it. It also has a spot to short across to get up to ~2 amps out.
 
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