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I'm working on my first electronics project. Basically I'm trying to control an rgb led strip from a raspberry pi's gpio pins. I'm trying to convert the raspberry pi's 3.3v up to the 5v required for the led strip. I bought these level converters https://www.amazon.com/gp/product/B0148BLZGE/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1. The docs for the level converters say both 3.3v and 5v need to be supplied at all times. Does this mean I need a seperate 3.3v power supply in addition to the led strips 5v power supply? This is assuming the GPIO pins should be sent through the channel pins on level converter and not through the 3.3v pin.

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  • \$\begingroup\$ There is a raspberry pi stack exchange web site. That said, there is 3.3V available from the Raspberry Pi. Just make sure you do not exceed the current limitations of the Raspberry Pi. \$\endgroup\$ – st2000 Jan 5 '18 at 1:44
  • \$\begingroup\$ Does the board you got match the amazon picture? Upload a clear picture of it. \$\endgroup\$ – Passerby Jan 5 '18 at 1:48
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    \$\begingroup\$ @st2000 this is not a RPi question.... \$\endgroup\$ – Passerby Jan 5 '18 at 1:48
  • \$\begingroup\$ The OP would benefit from people who know the RPi HW. Both the accepted answer and my comment draw upon our knowledge that there is 3.3V available from the RPi. Also, and no one has told the OP about this yet, there may be added difficulties controlling timing which may affect LED brightness or LED communications. As Linux is busy doing many thing where as an embedded processor (as on an Arduino) may only be controlling the LED brightness or only communicating to the LEDs. \$\endgroup\$ – st2000 Jan 5 '18 at 7:39
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That is a simple mosfet level translator. But there are two issues, see update:

enter image description here

It uses pull-ups to each voltage, to do the level translation from low side to high side, and back.

You need to connect the 5V power to the HV pin, the 3.3V power to the LV pin, and your GPIO to the appropriate pin.

The RPI has a 3.3V power rail you can use. It is fairly small in terms of current, but will work great for this purpose, as this circuit has a very low current need.

Update:

Based on the reviews on the amazon page, you either get a simpler board, with just mosfets and resistors, which work as I described above, or you get the pictured one, which includes a 3.3V regulator. In that case, all you need to connect is 5V, the Gnd, and the GPIO.

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  • \$\begingroup\$ I saw the 3.3v pin on the RPI but I assumed that was for powering the RPI and not for output. Should I wire the 3.3v pin on the level converter to another arbitrary gpio pin since they output 3.3v? \$\endgroup\$ – TheAschr Jan 5 '18 at 1:45
  • \$\begingroup\$ It would be better if you connect the 3.3V pin instead of a GPIO. The gpio get powered from that 3.3V rail. The issue with using the 3.3V rail too much is that it can't provide too much power, but your translator is not drawing that much power anyway. \$\endgroup\$ – Passerby Jan 5 '18 at 1:50
  • \$\begingroup\$ @TheAschr the more important question is which board did you get? \$\endgroup\$ – Passerby Jan 5 '18 at 1:50
  • \$\begingroup\$ I got the raspberry pi 2 model b if that's what you mean. The level converter I got is the one from the amazon picture. \$\endgroup\$ – TheAschr Jan 5 '18 at 1:52
  • \$\begingroup\$ Also should the ground from the 5v power supply be wired into both the level converter 5v ground and the ground from the led strip? \$\endgroup\$ – TheAschr Jan 5 '18 at 2:04

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