The Micrel MIC3223 constant current boost LED driver is capable of driving a series string of high-power LEDs and can be used in general architectural, industrial and ambient lighting, indicators, emergency lighting, signage lighting, bulb replacement, garden pathway lighting and other solid-state illumination applications.
The driver is a peak-current-mode control PWM boost regulator and the 4.5-20 V operating input voltage range allows multiple applications from a 5 or 12 V bus.
The device implements a fixed internal 1 MHz switching frequency to allow for a reduction in the design footprint size. Power consumption has been minimised through the implementation of a 200 mV feedback voltage with an accuracy of ±5%. It can be dimmed through the use of a PWM signal and features an ‘enable’ pin for a low-power shutdown state.
Features include step-up output voltage (boost) conversion up to 37 V, user-settable LED current (through external resistor) and externally programmable soft-start.
The LED driver provides overvoltage protection, thermal shutdown, switch current limiting and undervoltage lockout.