DC994A: 350mA x 3 Ch, 3 ~ 40V in

Demonstration circuit 994 features the LT3003 three channel LED ballaster with PWM in a 10-lead MSOP thermally enhanced MSE package. The demonstration circuit is designed to ballast three channels of LED current from 100mA to 350mA per channel. The PWM dimming function of the LT3003 eliminates the need for discrete MOSFETs. The LT3003 internally performs the level-shift required for non-ground referred PWM dimming in the buck mode and buck-boost mode topologies allowing PWM dimming input requirements to remain at logic-level. PWM dimming capabilities reach 3000:1 at 100Hz. Over temperature protection provides two open-collector pull-down outputs for direct interface with the compensation pin of most LT LED drivers and for use with a microcontroller. Additional thermal shutdown prevents the LT3003 from getting too hot.

The LT3003 can be configured in all LED driver topologies as long as there are three strings of LEDs and the pin voltage requirements are met. The boost, buck mode, buck-boost mode, SEPIC, and buck LED driver topologies can all use the LT3003 three channel ballaster with PWM. The shutdown pin can be tied to the switcher shutdown pin or in buck-boost mode it must be tied to the PWM pin.

When a single LED channel is open and has no current, the other two channels cut back their current to zero or almost zero in order to protect themselves. The LED current per string rating is between 100mA and 350mA. The maximum voltage on VMAX pin is 48V and the maximum voltage on VIN pin is 40V.

For more details, please see the datasheet.