Demonstration circuit 842 features the LT3474 constant frequency 1A step-down LED driver in a compact 16-lead TSSOP thermally enhanced package. The demonstration circuit is designed to drive a single Lumileds Luxeon III star white LED (included on the board) from a wide 6V to 36V input voltage range. The typical LED forward voltage at 1A is 3.9V.
The high switching frequency scheme permits the use of small inductors and ceramic capacitors to save space and cost. The current mode PWM scheme provides fast transient response and cycle-by-cycle current limiting. Frequency foldback and thermal shutdown provide additional protection.