Tiny Arduino LED driver

Here’s a nice trick I learned about when I was building an escape room. When using an Arduino to control LED tape, instead of building your own LED driver with MOSFETs, cheap LED amplifiers can be used. Here I stuck one to the back of an Arduino Nano for a super-compact driver.

The amplifier uses an quad opamp IC in an inverting comparator circuit to drive the MOSFETs. The IC compares 4.7 V from the Zener on the input voltage (VCC) pin to the input from the R, G, and B inputs. The MOSFETs switch the VCC to the RGB output pins. The Arduino only has to provide the PWM to the amplifier, the amp’s power input drives the LED tape. I’ve included a schematic, too. Note that the + input on the amplifier is NOT CONNECTED to the Arduino. The opamp uses the input voltage as the reference, and in fact connecting the + input to the Arduino will fry it (I learned that the hard way.) You should also have a common ground between the amplifier’s power supply and the Nano.

 

About Edward Carlson

Film and television Director of Photography working in Los Angeles, CA.
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