The LM3463 is a six channel linear LED driver with Dynamic Headroom Control (DHC) interface that is specialized for high power LED lighting applications. The variation of the output current of every output channel in the temperature range of -40°C to 125°C is well controlled to less than ±1%. The output current of every channel is accurately matched to each other with less than ± 1% difference as well.
By interfacing the LM3463 to the output voltage feedback node of a switching power supply via the DHC interface, the system efficiency is optimized automatically. The dynamic headroom control circuit in the LM3463 minimizes power dissipation on the external MOSFETs by adjusting the output voltage of the primary switching power supply according to the changing forward voltage of the LEDs. Comprising the advantages of linear and switching converters, the LM3463 delivers accurately regulated current to LEDs while maximizing the system efficiency.
The dimming control interface of the LM3463 accepts both analog and PWM dimming control signals. The analog dimming control input controls the current of all LEDs while the PWM control inputs control the dimming duty of output channels individually.
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The LM3463 provides a sophisticated protection mechanism that secures high reliability and stability of the lighting system. The protection features include VIN Under-Voltage–Lock-Out (UVLO), thermal shut-down, LED short / open circuit protection and MOSFET drain voltage limiting. The LED short circuit protection protects both the LED and MOSFETS by limiting the power dissipation on the MOSFETS.