The LT3478IFE#PBF is a 4.5A Monolithic LED Driver designed with true colour PWM Dimming designed to drive LEDs with a constant current over a wide programmable range. Series connection of the LEDs provides identical LED currents for uniform brightness without the need for ballast resistors and expensive factory calibration. The LT3478 uses an external sense resistor to extend the maximum programmable LED current beyond 1A and also to achieve greater accuracy when programming low LED currents. Unique circuitry allows a PWM dimming range up to 3000:1 while maintaining constant LED colour. One of two CTRL pins can be used to program maximum LED current. The other CTRL pin can be used to program a reduction in maximum LED current vs. temperature to maximize LED usage and improve reliability. Additional features include inrush current protection, programmable open LED protection and programmable soft-start.
True colour PWM? dimming delivers constant LED colour with up to 3000:1 range
4.5A, 60mR, 42V Internal switch
Drives LEDs in boost, buck-boost or buck modes
Integrated resistors for inductor and LED current sensing
Program LED current de-rating vs. temperature
Separate inductor supply input
Inrush current protection
Programmable soft-start
Fixed frequency operation from 200kHz to 2.25MHz
Open LED protection (programmable OVP)
Accurate shutdown/UVLO threshold with programmable hysteresis
(EN)
