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iDRV3 - New 3A Buck Driver

Blord

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That is a large capacitor compared to the 100uF cap. Are you sure that is a 10uF and not 50uF ?
My 10uF cap has the size of the two stacked SMD resistor.
 



grainde

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Yup I actually found out I could measure capacitance on my DMM and tested it before hand. It measured 9.98 uF on the DMM. :beer:
 
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foulmist

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That is a large capacitor compared to the 100uF cap. Are you sure that is a 10uF and not 50uF ?
My 10uF cap has the size of the two stacked SMD resistor.


there could also be small value resistors in larger sizes ;)
 

Meatball

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Hey.

Are the components on this board Q1 rated?

IE Are they rated for automotive performance?

EDIT: Also, what is the efficiency you've measured from this circuit? I'll need to calculate my PSU current draw.
 
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foulmist

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Hey.

Are the components on this board Q1 rated?

IE Are they rated for automotive performance?

EDIT: Also, what is the efficiency you've measured from this circuit? I'll need to calculate my PSU current draw.

the driver does work on car battery voltage range but I cannot know if it is rated for automotive performance.

the best effieciency is ~92% and worse is ~81%
depending on the input/output voltage difference

here are some numbers i just took:

[IN] - 1.55A x 8.4V
[OUT] - 2.56A x 4.11V
[EFF] - 81%

[IN] - 2.51A x 5.9V
[OUT] - 2.56A x 4.91V
[EFF] - 83%

[IN] - 1.25A x 12V
[OUT] - 2.56A x 4.91V
[EFF] - 84%

[IN] - 1.85A x 8.4V
[OUT] - 2.56A x 5.16V
[EFF] - 85%


[IN] - 2.27A x 8.4V
[OUT] - 2.56A x 6.54V
[EFF] - 88%

[IN] - 2.47A x 8.4V
[OUT] - 2.56A x 7.44V
[EFF] - 92%



:beer:

EDIT: maximum current draw from the powersupply is around 2.5A
 
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Meatball

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Hey thank you for the numbers!

Numbers are my favorite. :)

So this thing must dissipate 2.5W at worst. Not bad at all. :beer:

I'll start my design around these - It may take a bit to get it all sorted out!
 

rkcstr

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I have about 300 pieces (~290) of 0805 size 16V 10uF XR7 ceramic caps if you're looking for some. Have plenty of other SMT parts too, including a bunch of 1206 and 0805 sized resistors, if you have something specific you're looking for. I'll be happy to trade for a driver :)
 

Eradicator

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Finally got my caps, switched it out, tested the driver, everything was spot on. And I gotta say when I tested the driver, I did not have it heat-sinked yet, and it barely got warm to the touch, granted I only did a few 15 second or so runs I was still very surprised how cool it stayed at 2.4A with no heat-sinking at all.

Switched out my 2.2A x-drive with the 2.4A iDRV3 in my 9mm build, everything's working beautifully! Definitely an increase in brightness compared to my 2.1 A 9mm build. I think I'm probably over 3W now, gotta get this tested.

If anyone needs a cap for theirs still, I have 19 extra, and will send one to you for the cost of shipping. Shoot me a pm if you need one.

Thanks again foulmist! hope you have good luck selling these, they seem excellent to me.
 

foulmist

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Finally got my caps, switched it out, tested the driver, everything was spot on. And I gotta say when I tested the driver, I did not have it heat-sinked yet, and it barely got warm to the touch, granted I only did a few 15 second or so runs I was still very surprised how cool it stayed at 2.4A with no heat-sinking at all.

Switched out my 2.2A x-drive with the 2.4A iDRV3 in my 9mm build, everything's working beautifully! Definitely an increase in brightness compared to my 2.1 A 9mm build. I think I'm probably over 3W now, gotta get this tested.

If anyone needs a cap for theirs still, I have 19 extra, and will send one to you for the cost of shipping. Shoot me a pm if you need one.

Thanks again foulmist! hope you have good luck selling these, they seem excellent to me.

thanks :) I am glad you like it

:beer:
 

awillis2589

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I could use one! I'll pm you!

Also would one of those ram copper heatsinks on the underside be sufficient heat sinking at 2.2A? Or should I also put a piece on the IC.
 
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foulmist

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I could use one! I'll pm you!

Also would one of those ram copper heatsinks on the underside be sufficient heat sinking at 2.2A? Or should I also put a piece on the IC.

the IC has a thermal pad and there are lots of vias holes which transfer the heat to the bottom of the driver, no need to heatsink the IC on top.
 

djQUAN

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IE Are they rated for automotive performance?

the driver does work on car battery voltage range but I cannot know if it is rated for automotive performance.

Automotive usually means it should operate at an extended temperature range over 100degC

Electrically, the nominal 12V supply can have noise and ripple and can also have spikes of hundreds of volts lasting milliseconds (load dump) when electric motors (engine fans, wipers etc) and relays turn on/off so it should survive those too.
 

foulmist

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Automotive usually means it should operate at an extended temperature range over 100degC

Electrically, the nominal 12V supply can have noise and ripple and can also have spikes of hundreds of volts lasting milliseconds (load dump) when electric motors (engine fans, wipers etc) and relays turn on/off so it should survive those too.

as I said I can't be sure if it is automotive compatible
 

awillis2589

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got to love having a solder/reflow station. big thanks to Eradicator for the cap!!
 
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Blord

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Great job, that looks very smooth !
You have reflowed all components again ?
 
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awillis2589

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Thanks! no, I used the reflow gun with a small tip and heated the old cap and removed it then placed the new cap and reflowed it into place. just got this station like last Friday and already am in love!!
 




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