Boost controller simplifies LED backlighting

Diodes has introduced a constant frequency, voltage mode, external compensation boost controller.

The AL3022 is available in an SO-8 package and is said to significantly reduce the number of external components required for system design.

Operating at a fixed switching frequency of 140kHz, the controller handles up to 60W output power, and is suitable for a range of 14 to 42in LCD panel designs. In addition, it uses a 200mV voltage reference to help minimise losses, thus improving system efficiency.

The AL3022 supports both PWM and analogue LED string dimming control methods. PWM dimming is initiated by applying an external control signal of at least 100Hz, while analogue dimming is triggered using a DC signal ranging from 0.8 to 2.4V.

To improve overall system reliability, the controller offers a complete suite of integrated protection features. Included in the device are under voltage lockout, over voltage, over current and over temperature protection circuits, as well as protection against output to ground short circuits.