特点
True Color PWM? Dimming Delivers Constant LED Color with Up to 3000:1 Range
Wide Input Voltage Range: 2.8V to 36V
4.5A, 60mΩ, 42V Internal Switch
Drives LEDs in Boost, Buck-Boost or Buck Modes
Integrated Resistors for Inductor and LED Current Sensing
Program LED Current:
? 100mA to 1050mA (LT3478-1)
? (10mV to 105mV)/RSENSE (LT3478)
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
16-Pin Thermally Enhanced TSSOP Package
典型应用
典型应用
描述
The LT3478-1 reduces external component count and cost by integrating the LED current sense resistor. 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. Operating frequency can be set with an external resistor from 200kHz up to 2.25MHz. Unique circuitry allows a PWM dimming range up to 3000:1 while maintaining constant LED color. The LT3478/LT3478-1 are ideal for high power LED driver applications such as automotive TFT LCD backlights, courtesy lighting and heads-up displays. 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. Each part is available in a 16-pin thermally enhanced TSSOP Package.