An introduction to drive up to 40 white LED boost driver LT3599

Linear technology (Linear) company recently launched a 45V 2.1MHz DC/DC converter LT3599, boost mode, the device can be used as a constant current LED driver, can drive up to 40 white LED.

According to reports, LT3599 can drive up to 4 LED strings from a 12V input, and each string has up to 10 series of 120mA white LED, while providing up to 90% efficiency. Its multi-channel capabilities make this device very suitable for medium scale TFT-LCD backlight applications. LT3599 3.1V to 30V input voltage range is ideal for automotive, medical and industrial applications. The device offers 1.5% LED current matching to ensure consistent display brightness. Up to 3000:1 dimming ratio can be obtained by using True Color PWM dimming. Programmable 200kHz to 2.1MHz fixed frequency operation and current mode architecture provide stable operation over a wide supply and output voltage range while minimizing external component dimensions.

In addition, the switching frequency can be synchronized to an external clock to improve the anti noise performance. LT3599 uses a single 2A, 45V internal switch to provide a boost mode constant current source. However, even when the VIN exceeds VOUT, the LT3599 will continue to regulate the LED current. The internal boost converter adjusts the output voltage with an adaptive feedback loop that is slightly higher than the required LED voltage to ensure maximum efficiency. If any LED string is open, it will continue to adjust the existing LED string and send a signal to the OPENLED alarm pin. If you need a higher current LED, then you can combine multiple LED strings, so that it can drive up to two LED strings composed of 10 240mA. Other features include the LED current derating based on junction temperature / LED temperature, and programmable overvoltage protection when all LED series are disconnected.

LT3599's thermally enhanced 5mm x 5mm QFN or TSSOP-28E package provides a highly compact solution for LED backlight lighting applications that account for board area.