Small-footprint LED backlighting boost Controller

September 25, 2014 // By Graham Prophet
For TV and monitor manufacturers needing a cost-effective solution for driving LED backlights, Diodes Inc. has introduced a constant-frequency, voltage-mode, external-compensation boost controller. The highly integrated AL3022 is supplied in the small footprint SO-8 package and significantly reduces the number of external components required for system design.

Operating at a fixed switching frequency of 140 kHz, the controller handles up to 60W output power, and is suitable for a wide range of 14-in. to 42-in. LCD panel designs. The device uses a 200 mV voltage reference to help minimise losses. Delivering accurate line and load regulation, 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 100 Hz, while analogue dimming is triggered using a DC signal ranging from 0.8V 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.

The AL3022 boost controller is priced at $0.18 (100,000). The device is supported by a design note and an LED calculator for external component selection. An evaluation board (ref: AL3022EV1) is also available to qualifying customers.