Simple LED CCS

Simple constant current source (CCS) to drive one ore more LEDs

This circuit is a simple constant current source to drive one or more LEDs based on a LM317 and some additional components.

I’m using this circuit on my Mikrokopter to drive 4 Rebel LEDs with a total current of 400mA .

Dependent on the current drawn by the load it is highly recommended to use a heatsink for the MJE15030 or fix the whole PCB to a heatsink. An alloy based PCB would be even better.

Electronic circuit (Click for better resolution)


Schematic

Components (Click for better resolution)


Components

Layout (Click for better resolution)


Layout

Schematic and PCB
Schematic and PCB
LED_KSQ.pdf
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3 thoughts on “Simple LED CCS

  1. How many Led’s (max) i can drive by using this circuit. I trying to designing LED matrix display with constant current drivers with my multiplexing technique. So that I can consume less power than conventional LED matrix.

    • The limiting part here is the MJE15080 transistor that controls current. The transistor is rated for 8A continuous current. Keep in mind that with increasing current this transistor must be mounted to an appropriate heatsink. Also PCB traces must be enlarged to deal with the current. So my example layout might not be suited.

      About how many LEDs you can drive? Well it depends on you supply voltage and the way you connect these LEDs together, series, parallel, mixed etc.

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