Diodes Incorporated introduced the AL8860. This hysteresis mode DC-DC step-down converter 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 4.5 V and 40 V, the AL8860 can directly source a 1 A output current in the TSOT25 package, or up to 1.5 A 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 watts of output power.
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| AL8860 Typical Applications Circuit. |
In addition to the internal 40 V 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 0.2 V 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 overtemperature to ensure reliable system operation.
