I have been trying to find a suitable circuit that will let me us the logic of an atmel chip to switch or dim a run of SMD3528 300/5m LED Strips. I estimate I will need 12V with a max of 8-10Amps (The Comparison Between SMD 3528 and SMD 5050 LED Strip Lights : LEDLIGHTSWORLD.CO – LEDLightsWorld). Does anyone have a suggestion for any simple yet rugged circuits??
Thanks ahead of time.
Here is a MOSFET driver circuit. PWM dimming will work through that driver. It's shown with a motor but it will also work with LED strips. Since LEDs are non-inductive you can leave-out the diode.
Of course, the MOSFET should be rated to handle the current, plus some safety margin. It's "good practice" to use a component rated at twice the required current or more. You'll probably also need a heatsink.
If you have an RGB strip and you want to control the colors separately you'll need 3 drivers (and each only needs to handle 1/3rd of the current).
Note - That's a LOT of amperage and if you run one-long strip you'll get a voltage drop and the LEDs at the far-end will be dimmer than the LEDs close to the power supply. This is related to the resistance of the thin conductors built-into the LED strip (Ohm's Law). If you can run some thicker power-wires to both ends that should help but it may still be dim in the middle. I don't know if you can (easily) connect in the middle.
This is from your link:
- When the strip make into a 5M full roll, for there is voltage drop, there will be lost on Lumen.
Excellent circuit. All the others I have seen had 1-2 transistors and a mosfet.
As far as the voltage drop, I appreciate the reminder. I run a lot of 5v WS28XX lighting, where the voltage drop does happen and happen pretty darn quick. That is why I decided for this project to stay with simple warm white LED Strips and just use a dimmer circuit.
My game plan is in the attachment. I know if i feed both ends of the strips, it should be better than just feeding them from one end like one long strip. if i see issues, I will splice in injection points in the middle of each run.
Per that link I am planning on using the following:
Mosfet = https://www.taydaelectronics.com/irl2203-mosfet-7-ohm-116a-30v-n-channel-to-220-3-irl2203npbf.html
Resistors = I already have 1/2 watt resistors of that type.
Now to draw out the circuit. the final project will have the following (and yes I went big)
4 switches with 2 capacitive sensors each (Up and down)
4 PIR sensors (if no activity for 20 mins, dim the lights)
remote access via website
just have to design some PCB’s now