1 Watt Led Driver Circuit

A high efficiency greenpoint solution.

1 watt led driver circuit.

Once you have understood the circuit you can calculate the current rating required for your led and build it on a breadboard to test it. 1 watt to 5 watt led driver solution for high brightness leds. For making 350ma you must sink 350ma from source. To wire a series circuit like the one shown the positive output from the driver connects to the positive of the first led and from that led a connection is made from the negative to the positive of the second led and so on until the last led in the circuit.

C1 together with the inductor l0 and c2 make up a pie filter network for cacelling emi disturbenaces. My circuit looks like as shown below after i built it on a breadboard. It can be directly driven from any domestic 220v ac or 120v ac mains outlets. Good 1w leds are typically 350 ma at 2 9v 1 watt the rest will have higher tolerance on vf e g.

I got the concept of this circuit few years back from a led torch which was powered by a single aa battery. Configured in size and features for mr16 led replacements. So current need is 1 3 2 312ma that normal current is 350ma. The input mains 220v or 120v ac is half wave repaired by d1 and c1.

And the only way to change the led brightness is to change r3 so refer to the earlier schematic for circuit 5 which shows adding a low high power switch in. Using strings of 4 gets you almost 12v with a 2 9v led. The concept it to try to determine a running current by using the inductor diode and load at the same time the switch fills up the missing load energy on a single cycle. You need a constant current for turn on led and this led is power led 1 watt with 3 2 volt.

Buck boost switching regulator topology. Here a simple 1 watt led driver circuit based on a modified joule thief design runs on a 1 5v single aa or aaa cell. Non isolated constant current operation. 3 4 running a 3v led from a 12v supply with a series regulator and series resistor is going to be 3 12 or 25 efficient alone.

The image to the right shows an example. The simple 1 watt led driver circuit buck converter presents approximately 90 efficiency. Capacitor need is 5uf 400v but this is very big capacitor and burn after 24h work. This circuit is pretty efficient and it can power a 1 watt white led quite brightly.

Led current in amps 1 25 r3 so for a current of 550ma set r3 to 2 2 ohms you ll need a power resistor usually r3 power in watts 1 56 r3 this circuit also has the drawback that the only way to use it with a micro controller or pwm is to turn the entire thing on and off with a power fet. P 1 1 1 25 1 25watts working of led driver circuit. Auto detect function allows 12 vdc or 12 vac input while maintaining the targeted output current.