Cheapest High power LED driver circuit diagram
If you came here through Google, then you might have seen other circuits too for high power LED driving which consists of much parts, like inductors, op-amps, different regulator IC’s , transistor feedback networks, microcontrollers etc.
Those circuits are more efficient than this one but the making expense and difficulty is much more high and so I am here showing you the simplest high power LED driver circuit.
Look at this article to make DIY LED driver for 5Watt LEDs, and 12V strips from 100-240 VAC
In market, we can get 1Watt and 3Watt LED easily. And the ratings of those 1Watt LEDs are Forward Voltage 3.2V – 3.6V, Forward Current 300mA and for the 3Watt ones,m the ratings are Forward Voltage: VF 3.4V , Forward Current :700mA .
So we consider 3.4volts as optimal voltage, and thus the 1watt LED is giving 3.4×0.3=1.02Watt and for 3watt it is, 2.38Watts.
So here’s the simplest circuit that can be used.
Here, for a fixed reference supply, LM7805 regulator I.C which can deliver upto 1Amps of current, and in our cases the max required current is 700ma or 0.7Amps, so no problem there. And since the resistor “R” will be eating the extra 1.6 volts(5.0-3.4). So what would be the value of R?
For 1 watt model, there’s current of 300mA, so the value of the resistor should be 5.3 Ohms(appx) and wattage should be 0.48. So a 5.6ohms 1/2watt general purpose resistor will do the job perfectly. And similarly, for the 3Watt model, the value of R would be 2.2Ohm 1.25Watt(or 2Watt).
We can feed any voltage greater than 5.5 volts, so we can run this circuit in 6Volts supply or in 12 volts supply.