DC/DC LED driver provides up to 40W output

11th November 2016

Enaie Azambuja

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Datasheet

Diodes Incorporated has introduced the AL8860 hysteresis mode DC/DC step-down converter, which is designed for driving single or multiple series‑connected LEDs efficiently from a voltage source higher than the LED voltage. With its integrated MOSFET, this product provides a low BOM cost solution for low-voltage industrial and automotive LED lighting applications, including illuminated signs and backlighting, as well as an LED retrofit for replacing low-voltage halogen lamps.

Operating from an input supply between 4.5V and 40V, the AL8860 can directly source a 1A output current in the TSOT25 package, or up to 1.5A in the more thermally efficient MSOP8-EP package. Contingent on the supply voltage and other external components, the AL8860 is capable of providing up to 40 W of output power.

In addition to the internal 40V 0.2 ohm NDMOS power switch, the device integrates a high‑side output current sensing circuit that allows the use of a single external resistor to set the nominal average output current. Deep dimming (0% to 100%) can be applied via a CTRL pin using either a DC voltage or a PWM signal.

The same pin also implements soft-start operation, with the time adjusted by an external capacitor. Applying a voltage of 0.2V or less to this pin will turn off the output and cause the device to enter a power-saving standby state.

The AL8860 includes protection against LED short and open circuits, and over-temperature to ensure reliable system operation. Offered in either the 5-pin TSOT25 package or 8-pin MSOP8‑EP package the AL8860 is priced at $0.15 and $0.18 each respectively in 1000 piece quantities.