|26NOV13||Got featured on Hack a Day http://hackaday.com/2013/11/20/simple-10-watt-led-driver-is-hot-stuff/|
|17NOV13||New design work is done and is up and
If anyone is interested I have a extra LED and fully assembled driver card left over for sale.
|Download the full package (micro code and
PCB data) here [10W_LED_driver.zip].
The core of this project is a PIC12F1501 and CAT4101 led driver. The CAT4101 is the LED constant current driver and takes care of controlling and driving the LED. The PIC12F1501 is used to control the dimming via PWM, Fan control (either PWM or just on / off), and tracking the user input via the buttons. One button increases the brightness from off though 10 levels ending in full brightness while the other decreases the level. Pressing both buttons at once will skip from off to full on or if already on to off.
Other than this card just a power supply and a LED (or string of LEDs) are required to complete this setup. When choosing the LED (or string of LEDs) keep the following in mind. The maximum supply voltage for the CAT4101 is 25V and requires 0.5V drop for the regulator. So the maximum LED (or string of LEDs) voltage can be is 24.5V. When choosing the power supply it must be greater than your max LED (or string of LEDs) voltage, less than 25V, and less than your LED (or string of LEDs) on voltage plus 6V. LED current can be anything 1A or under and is set by R1 in the design.
There is also 2 optional outputs on J2. Pin 5 is a TTL output that is low when the LED is fully off and high all other times. Pin 4 is a PWM fan output. Current firmware sets this ping up to be low when fully off, 25% PWM for brightness levels 1-5 and 44% PWM for brightness levels 6-10. Fan PWM levels can be updated in the top of the assembly code and recompiled if needed.
More information on circuit set up is available on my instructable here: http://www.instructables.com/id/10W-LED-driver-and-dimmer/