PAGE 117 OF 150 · MICROCONTROLLERS & LEDS
Powering Addressable LED Strips
Many LEDs at full white can draw a lot of current.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
Plan the current
At full white each pixel can take 60 mA, so a metre of 60 pixels needs up to 3.6 A at 5 V. Real displays use much less, but the supply must handle the worst case you allow.
Good practice
- Use a 5 V supply rated above your calculated current.
- Connect supply ground and controller ground together.
- Add a 1000 microfarad capacitor across the supply at the strip.
- Feed power in at several points on long strips.
- Limit brightness in software.
Switch the supply on before or with the data signal.
REMEMBER
Share a ground and size the supply for full white.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
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