High power led driver using LM3434
Using the LM3434 adaptive constant on-time DC/DC buck (step-down) constant current controller can be designed a very simple high power led driver application . The LM3434 provides a constant current for illuminating high power LEDs.
The output configuration allows the anodes of multiple LEDs to be tied directly to the ground referenced chassis for maximum heat sink efficacy. The high frequency capable architecture allows the use of small external passive components and no output capacitor while maintaining low LED ripple current.
Two control inputs are used to modulate LED brightness. An analog current control input is provided so the LM3434 can be adjusted to compensate for LED manufacturing variations and/or color temperature correction.
As you can see in the schematic circuit this high power LED driver circuit require few external components and can provide a maximum output current of 10 amperes .
The PWM functions by shorting out the LED with a parallel switch allowing high PWM dimming frequencies. High frequency PWM dimming allows digital color temperature control, interference blanking, field sequential illumination, and brightness control. Some additional features of this high LED driver project include thermal shutdown, VCC under-voltage lockout, and logic level shutdown mode.
For this power supply project you need to use a logic power supply 3.3 volts typically and a dual 12 volts ( plus , minus 12 volts ) for powering the driver . For this power LED driver circuit diagram you can use some MOSFETs transistors like : Si7386DP, Si7668ADP , Si7790DP , NTMFS4841NHT1G or other similar types .
All components marked with * , Q3 transistor and the 68 uF value capacitor from CGND pin are used are required just if PWM dimming is used .