I am a software developer by trade and have little or no experience regarding LED and/or electronic designs. I am hoping someone here can help with a project I am working on using high brightness LEDs. I have studied several 'instructables' and specifically dan's 'Circuits for using High Power LED's.'

Simple High Power LED 10W 12 Volt Driver circuit, by using one transistor and other cheap components. Computer Performance Score Vista here. See circuit and making this tested Driver Circuit. This is a simple 230v LED Driver circuit diagram which is used for home lightening systems and also can be used as an indicator.

My project consists of a few high brightness LEDs that will be placed in a high ceiling room with the brightness controlled by a microcontroller based on the light in the room (time of day, sun in window, etc). The microcontroller will use photocells to determine the brightness in the room and then adjust the LED using PWM pins.

The LED is 10 watt and approximately 450 lumens. Attached is a circuit I drew as a starting point and would like help in determining if it will work, I am close or does it need to be trashed. I am not sure what the value for the resistor should be. Below are some calculations but not sure if I am on the right track or not. No need to be kind, I am more interested in getting it right and not losing any 'magic puffs of smoke' from any of the components. Here are the specs: LED IF: 1.6 A Peak Forward Current: 1.7 A Forward Voltage: 8 V LM350 (heavy duty version of LM317 IO_MAX: 4.5 A 1.2 - 25 V adjustable regulator BC337-40 Collection Current - Continuous: 800 mA dc Total Device Dissipation: 625 mW Resistor: 5W or 10W Voltage Amp Ohms Watt 8 1.60 5.0 12.8 8 0.80 10.0 10.0 8 1.10 7.5 8.5 Note: LED and components will have adequate heat sinks.

Hey everybody! I've got some more steamy, explicit, pics of homemade LED driver circuits.

The circuit shown in the pictures below is a Buck-type switching circuit featuring a NDP6020 P-channel MOSFET, a MBR2045 fast diode, a 150 uH inductor made from 44 turns of 24 AWG insulated wire wrapped on a ferrite donut I pulled out of a dead computer power supply, and a 0.1 ohm current sensing resistor. Those are the guts of this circuit. The brain (or maybe it's the heart?) of this circuit is provided by TI's SG3524 PWM driver, plus two op-amps, TLC272, plus various resistors and capacitors. Basically what's going on here is not too different from the negative feedback loop in the linear style LED driver circuit I posted previously. The current through the LED is sensed with the 0.1 ohm current sensing resistor, then this signal is amplified with a non-invering amplifier, then compared to a desired reference level, and then this error is fed to an integrator.