LM3433 LED Driver

Texas Instruments' LM3433 is an adaptive constant-on-time DC/DC buck constant current controller. It provides a constant current for illuminating high power LEDs. The output configuration allows the anodes of multiple LEDs to be tied directly to the ground referenced chassis for maximum heat sink efficiency. The high-frequency capable architecture allows the use of small external passive components and no output capacitor while maintaining low LED ripple current. Two control inputs are provided for LED brightness control. An analog current control input is provided so the LM3433 can be adjusted to compensate for LED manufacturing variations and/or color temperature correction. The other input is a logic level pulse width modulation (PWM) control of LED current. The PWM functions by shorting out the LED with a parallel switch allowing high PWM dimming frequencies. Additional features include thermal shutdown, VCC under-voltage lockout, and logic level shutdown mode.