The LT3956EUHE#PBF is a Constant-Current Constant-Voltage DC/DC Converter ideally suited for driving high current LEDs. It features an internal low side N-channel power MOSFET rated for 84V at 3.3A and driven from an internal regulated 7.15V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size. High side current sensing is the most flexible scheme for driving LEDs, allowing boost, buck mode or buck-boost mode configuration. The PWM input provides LED dimming ratios of up to 3000:1 and the CTRL input provides additional analogue dimming capability.
3000:1 True colour PWM? dimming
Internal 3.3A/84V switch
Constant-current and constant-voltage regulation
250mV High side current sense
Drives LEDs in boost, buck mode, buck-boost mode, SEPIC or Flyback topology
100kHz to 1MHz Adjustable frequency
Open LED protection
Programmable under-voltage lockout with hysteresis
Constant-voltage loop status pin
PWM disconnect switch driver
CTRL pin adjusts high side current sense threshold
(EN)
