MIC3223 High Power Boost LED Driver with Integrated FET
Created: Aug 25, 2016
No description available.
In driving LEDs, a constant current output is a preferred method to the constant voltage. The small variations in current have a minimal effect on the light output, whereas small variations in voltage have a significant impact on lights output. The circuit is a high power boost LED driver with integrated FET of the MIC3223. The MIC3223 is a constant current boost LED driver capable of driving a series string of high power LEDs. It has a 200mV feedback voltage with an accuracy of +5%. It is a peak current mode control PWM boost regulator and the 6V and 20V operating input voltage range allows multiple applications.
The MIC3223 is designed to operate as a boost converter, where the output voltage is greater than the input voltage. In boost configuration, the output can be set from Vin up to 37V. This configuration allows for the design of driving multiple LEDs in series to help maintain color and brightness. It has a low impedance gate driver capable of switching large MOSFETs, which provides high operating efficiency. The LEDs can be dimmed through the use of a PWM signal (DIM_IN pin) and features an enable pin for a low power shutdown state. The RADJ (R5) is the feedback voltage and error amps output of the PWM comparator of the MIC3223. The current through the LED string is set via the value chosen for the current sense resistor RADJ (R5). The rectifier diode used is an Schottky diode, because of the lower forward voltage and the low reverse recovery time.
The MIC3223 is a very robust LED driver and offers the protection features like over voltage protection, thermal shutdown, switch current limiting and under voltage lockout. It can be used in applications like general lighting, signage, landscape pathway lighting and other solid-state illumination.