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FrozenGate by Avery

New boost driver with IMS PCB

DTR said:
Wow that look awesome. Great work.:beer:

Would you have the ability and desire to post a test video for us like the one below. The main thing I would like to see is if the current stays constant @ 1.8A as the voltage decreases. Here is one I tested that did not.:yh:
Click to expand...

Ok, i will try soon.
 





laserluke;

Very nice job on the metal core pc board.

As we go to higher power levels, these will be needed for heat dissipation.

To achieve long run times, heat rise of the IC is critical.

The multi-turn pot is a good feature.

I'll have to look into the feasibility of that 25mm board in some of my builds.

LarryDFW
 
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Great job on the layout and good idea with the aluminum core board!
Let me guess: LT1370HV? 0.01Ohm Rsense, something like INA168 and pot adjustable gain?
 
theoretically, the input current should increase as voltage decreases, right? If it stayed constant, then it would indicate something is wrong.
 
BShanahan14rulz said:
theoretically, the input current should increase as voltage decreases, right? If it stayed constant, then it would indicate something is wrong.
Click to expand...

That is how I understand it. If voltage drops either the input current would need to increase or the output current would need to decrease with a boost driver.

I believe that was what was wrong with several of the previous drivers I tested. Although the circuits were set up to be constant current they seems like there was a max current the circuit could handle as a draw from the power source so when it hits this limit the output current had to decrease because that was the only thing left to give. On the one in the video above it seemed to be around 3.5A.;)
 
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Above, you will see that I just learned that the switch current will give a theoretical maximum. I'm guessing things like trace cross-section and other component specifications can trim this down more.

It's also good to see what current draws can be expected on the entire range of the power source that the build will finally be using. Even if I can't understand what parts cause this ceiling that the current cannot go over, at least I'd know how much current it would be pulling from my power source. I wish more people would post info like that :)
 
This is also a good reason for finding the most efficient driveres. Here is dual flexes set to 1.7A(I will try to find one @ 1.8A as I know I have one somewhere) and it is still under 3A current draw @ 3.5V.:eg:

 
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BShanahan14rulz said:
Above, you will see that I just learned that the switch current will give a theoretical maximum. I'm guessing things like trace cross-section and other component specifications can trim this down more.

It's also good to see what current draws can be expected on the entire range of the power source that the build will finally be using. Even if I can't understand what parts cause this ceiling that the current cannot go over, at least I'd know how much current it would be pulling from my power source. I wish more people would post info like that :)
Click to expand...

A "key component" is the inductor. At each cycle it stores an energy of 1/2LI^2 Joules. To operate in continuous mode this energy must be the same at the beginning and at the end of a cycle. Under this condition the duty cycle is 1-Vi/Vo.
If the energy is too low the inductor may be completely discharged before the end of a cycle and the converter operates in discontinuous mode. Under this condition the output voltage depends on the switching frequency, inductor, input voltage, output current and duty cycle and the expression is much more complicated (Vo/Vi=1+(T*Vi*D^2/2*L*Io)).
Trying to compensate for such low energy, the current control circuit increases the duty cycle and reaches the maximum...
...the inductor MUST be carefully chosen...
 
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DTR said:
Wow that look awesome. Great work.:beer:

Would you have the ability and desire to post a test video for us like the one below. The main thing I would like to see is if the current stays constant @ 1.8A as the voltage decreases. Here is one I tested that did not.:yh:
Click to expand...

This is the output's current stability test from 4V to 3V input. Output current is fixed at 1.8A.

 
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laserluke said:
This is the output's current stability test from 4V to 3V input. Output current is fixed at 1.8A.

Click to expand...

that's looks great but where is the input current?
can you show a video with input current as well?

when using a battery is a whole different story.. :)

:beer:
 
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foulmist said:
that's looks great but where is the input current?
can you show a video with input current as well?

when using a battery is a whole different story.. :)

:beer:
Click to expand...

For the diode shown in the video the driver's input current at 3.7V is 3.1A.
Do you believe me? :beer:
Do you need a video for every word that is asserted? :beer::beer:
Do you feel in a race? :beer::beer::beer:

And finally, as you certainly know... even with a properly designed driver you need also a good battery with a low resistance...
:wave:
 
laserluke said:
For the diode shown in the video the driver's input current at 3.7V is 3.1A.
Do you believe me? :beer:
Do you need a video for every word that is asserted? :beer::beer:
Do you feel in a race? :beer::beer::beer:

And finally, as you certainly know... even with a properly designed driver you need also a good battery with a low resistance...
:wave:
Click to expand...

I was just curios :D :beer:
 
DTR said:
Looks great.:beer:

Do you know what the current draw was @ 3.6V?
Click to expand...

As supply voltage decreases, the supply current increases exactly as any other driver. The minimum supply voltage is 2.4-2.7V. For voltages of about 3.7V the current is about 3.1A.
 
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