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questions about micro boost drive

Morgan

Morgan

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I have noticed while setting the MicroBoost using my bench PSU that if the current draw is not met for any particular output setting, the driver seems to go into shutdown in the same way that the Flexdrive does when voltage is not met. In fact I now remembering noticing that the output current did start to fall away too.

I found the same scenario as posts above that testing with the PSU, below the current draw to achieve the output, did not give good readings but tested on a fresh battery of sufficient charge, and the setup worked fine.

The current draw for these seems to be higher than you would perhaps think. IIRC for my testload using 6 diodes I was looking at around 800mA draw for a 500mA output, (around 600mA when diode was installed).

Are we any closer to understanding what's going on with your setup ndrew2505?

M
:)
 





P

proud2deviate

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I'm having this exact same problem with two different Boost drives. I PM'd Dr. Lava, hopefully he'll have an answer for me.

The lowest three current ranges work perfectly, it's when I bridge to R510 that things go south.
 
jayrob

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I love the driver though... It has a much nicer pot for adjusting too...

So I've just decided that if I set it in the 540-1000 range, then it must have a Li-Ion battery is all...
 
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ndrew2505

ndrew2505

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i said the heck with it...

it seems it was a combo of power supply issues and test load issues so i just maxed out the pot and hooked the diode up.. puts out about 950mw though im not sure of the exact current.
 
ndrew2505

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Pontiacg5 said:
lol

Its funny that the drivers are limiting our diodes now :D
Click to expand...

dont forget about the problem with readily available test loads.. the test load failing was why i dont know the exact current..

this thing EATS 16340 batts for lunch... i just put one in a little while ago that was fully charged. its almost dead to the point the driver started flashing on and off.. the flexdrives used to do that when the batts got really low.. got less than 15 min runtime off a fully charged battery...
 
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SHIN

SHIN

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I experienced the similar problem...
Especially around 800mA to 1A.

I wonder if the current of dummy load is the problem....
I don't know the maximum forward current of 1N4001. About 1A?

Is there anyone knows electronics?

SHIN
 
drlava

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The dummy load you're using has two settings, one for blu ray and one for red. However the blu ray setting at these currents is the wrong one to use, it stresses the driver too much. You can use the red setting in this case. Try this, and the 5V input voltage and it should be fine.
 
Bionic-Badger

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Heh, I could smell my dummy load "cooking" when I did the current testing. Fortunately, I only had it on for a little bit during tests.
 
Morgan

Morgan

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drlava said:
The dummy load you're using has two settings, one for blu ray and one for red. However the blu ray setting at these currents is the wrong one to use, it stresses the driver too much. You can use the red setting in this case. Try this, and the 5V input voltage and it should be fine.
Click to expand...

Interesting!

So, if I only use three diodes of the test load, (Red setting), the volt drop will be around 2.1 volts, (0.7V per diode). If set to, (randomly), 678mA, will the output remain at 678mA even when the LD requires 4.1V?

This question has been in my mind for a while but it's never come up to ask before. If the answer is yes to the above question, is there any reason to ever change the setting from Red on my test load? Even using a Flexdrive for a BR? If it's a complex answer then it's fine BTW. I may not immediately understand it but I will research so that I do eventually.

Thanks,

M
 
jayrob

jayrob

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drlava said:
The dummy load you're using has two settings, one for blu ray and one for red. However the blu ray setting at these currents is the wrong one to use, it stresses the driver too much. You can use the red setting in this case. Try this, and the 5V input voltage and it should be fine.
Click to expand...

Thanks for responding with this information!

I did try it with a red test load and had no problems at with setting the driver with a 3 volt supply in the 540 - 1000 range... :)

Glad to know that it was just a test load issue...

Edit: Red test load yes. 445 diode no. (at least not with the phaser sound board)

Update: The Micro BoostDrive is fine for 445 diodes in the 540-1000 range using a 3 volt supply without the phaser sound board.

Will try a FlexDrive with this diode in the Phaser next...

Update 2: V5 FlexDrive set at 650mA's works perfectly stable with the 445 diode in the Phaser with sound board and LED. (3 volt supply) :)
 
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Wallydraigle

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I'm experiencing the same thing. I actually melted one Micro Boost. I didn't notice anything wrong until I let out the magic smoke and by the time I got it disconnected parts had actually desoldered themselves. I just figured I messed something up. So I tried again more carefully with another one. Same thing, up around 700-800mA it gets really hot. I'll try a test load configured for a red diode and see how that works.
 
jupiter8

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Doesn't take much to have a runnaway situation with current and resistance like that, if there's a slightly under-spec power transistor for instance, at the top end of the range it's running close to maxed out. At currents where heat dissipation is greater than or equal to heat generated, no problem, cross that line and meltdown. As you know resistance increases with heat, increased resistance - more heat, more resitance, more heat - exponential runnaway. What do you think?
 
Xplorer877

Xplorer877

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The problem is the driver efficiency. Depending on what your pot is set to you can have between 76-86% efficiency. That is pretty good but not good enough with super high currents now. If the diode is eating up 4.4W the the driver has to dissipate about .7 watts at best. That's alot for those little components.

-Tony
 
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Morgan

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I think it's pertinent to remember is that the Microdirve was developed for BRs only and this new, "445", kid on the block wasn't part of the original design.

It may cope well under certain training conditions but I feel another driver may be being thought about as we speak.

I hope that's the case anyway. Good luck Dr.Lava, the need is here, so the product will be purchased!!!

M
:)
 
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jayrob

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It works just fine with Li-Ion's...

It even put out high current for a tiny 10280 in one of my tests...

Then only problem I had was using a 3 volt supply with the phaser sound board. It worked fine without the phaser sound board using a 3 volt supply...
 
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