Diodes Incorporated's LED Driver Simplifies Low-Voltage Low-Cost Lighting Design

Diodes Incorporated announced an LED driver tailored to fit low voltage illumination products operating at between 6V and 30V. The AL8805, a 1A rated buck mode constant current switching converter, will support up to ten 3W LEDs connected in series, suiting a range of low cost 'safe electrical' designs including the ubiquitous MR16 lamp. The driver's typical constant current output accuracy of 5%, irrespective of source voltage and LED chain length, is more than sufficient to meet the needs of low cost lighting products, ensuring uniform LED brightness and good inter-lamp matching without the need for ballast resistors.
With nominal output current determined by external resistor setting, LED dimming is simply achieved by either a DC voltage or PWM signal on the AL8805's control input. A DC voltage between 0.5V and 2.5V yields an output current between 25% and 100% of nominal, while a PWM signal between normal CMOS or TTL levels offers a highly flexible 1000:1 dynamic dimming range. On/off control is provided via a <0.4V signal applied to the same control input. The LED driver's enhanced switching speed and low on-resistance provide 1MHz switching frequency capability which reduces the size of the external components required in thermally demanding environments. The AL8805 is provided in the SOT23-5 package.