A very simple high efficiency LED driver circuit project can be designed using the LM3414 and LM3414HV which are 1A 60W* common anode capable constant current buck LED drivers. LM3414 , LM3414HV are suitable to drive single string of 3W HBLED with up to 96% efficiency and accept input voltages from 4.5VDC to 65VDC and deliver up to 1A average LED current with ±3% accuracy. The integrated low-side N-channel power MOSFET and current sensing element realize simple and low component count circuitry as no bootstrapping capacitor and external current sensing resistor are required. An external small signal resistor to ground provides very fine LED current adjustment, analog dimming as well as thermal fold-back functions. As you can see in the circuit diagram , these LED driver circuit design require extreme low external parts . This constant LED driver electronic design project can drive up to six high power LEDs . For this LED driver project you can use LM3414 or LM3414HV circuit , the difference is that if you’ll use LM3414HV driver you can power the circuit from a DC voltage up to 65 volts ( LM43414 accepts an input voltage up to 42 volts ) . The minimum input voltage range for this project is 24 volts DC .