However I realize that the finding and configuring the power supply is still not as simple as it can be; commercially available LED drivers are convenient, but often overkill or not flexible. Even my own Universal LED Driver can be overkill at times. Some projects call for a bear minimum, simple driver.
Poorman's Buck - Simple, Constant Current LED Driver
So I created the "Poorman's Buck" - simple switch-mode (buck) constant current LED driver that's built without a microcontroller or a specialized IC. All of the parts are easy to obtain, "off-the-shelf", though-hole parts.
Even though this driver is minimalistic, I added a current adjust function that doubles as a dimmer, and an input to control the output with PWM. This makes the "Poorman's Buck" perfect building block for Arduino or other microcontroller based LED projects - you can control many high-power LEDs from a microcontroller simply by sending PWM signal. With Arduino you can simply use "AnalogWrite()" to control the brightness of high-power LEDs.
Step 1: Features
- Inductor "switch mode" (buck) converter for high energy efficiency.
- Wide supply voltage range of 5 to 20V. Great with batteries as well as AC adaptors.
- Cycle-by-cycle, true constant current circuit
- Configurable output current up to 1A
- Up to 15W maximum output power. (at supply voltage 20V with five 3W LEDs connected)
- Current control potentiometer (trims the output current down to about 9%)
- Current control can be used as a built-in dimmer
- Output short-circuit protection
- PWM control input - controllable via external microcontroller including Arduino.
- Compact design - only 1 x 1.5 x 0.5 inches (excluding the pot shaft)