Date: 15/09/2010

LED driver from Diodes Inc for low voltage illumination products

Diodes has introduced a LED driver designed to fit low voltage illumination products operating at between 6V and 30V. The AL8805, a 1A rated buck mode constant current switching converter, supports up to ten 3W LEDs connected in series, suiting a range of low cost 'safe electrical' designs including the ubiquitous MR16 lamp.

The driver has a typical current output accuracy of 5%, irrespective of source voltage and LED chain length. Diode Inc. says that this LED driver ensures uniform LED brightness and good interlamp matching without the need for ballast resistors. The nominal output current is determined by external resistor setting. The LED dimming is acheived by 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.

Package: AL8805: SOT23-5