18 October 2011 Linear led driver simplifies low power led control Integrating a high gain NPN transistor with a 30V rated pre biased NPN output transistor, the AL5802 linear led driver from Diodes is designed to provide a simple, cost effective and low EMI solution for controlling current in up to nine low power series connected leds. The new device features an open collector output, which is capable of operating between 0.8 and 30V, and supports 12 and 24V power supplies to deliver led currents between 20 to 100mA for led signs, lamps and automotive interior display applications. The led current is set via an external low value resistor, the one additional component required by the driver. By generating a reference voltage of 0.65V across the resistor, the internal high gain transistor helps minimise power losses and ensures supply voltage headroom. According to Diodes, the negative temperature coefficient of the reference voltage means that led current is automatically reduced at high temperatures, thereby helping to protect leds and improve circuit reliability. PWM dimming of the led string is said to be simple to achieve by either driving the device bias pin with a low impedance voltage source or driving its enable pin with an external open collector NPN transistor or open drain N Channel mosfet. In addition, the SOT26 packaged AL5802 has an ambient temperature operating range of -40 to 125ºC, which the company says enables it to be circuit mounted very close to the leds in space limited lighting applications. Author Laura Hopperton Comment on this article Websites http://www.diodes.com Companies Diodes Incorporated This material is protected by Findlay Media copyright See Terms and Conditions. One-off usage is permitted but bulk copying is not. For multiple copies contact the sales team. Enjoy this story? People who read this article also read... Alternative back-up power With outdoor events like concerts, events and festivals now ... Read Article NIDays 2013 NIDays is a technical conference designed specifically for ... Read Article Southern Manufacturing This year, Southern Manufacturing and Electronics is set to be ... Read Article Microcontrollers deliver ... Microchip has launched what it describes as the 'world's lowest ... Read Article What you think about this article: Add your comments Name Email Comments Your comments/feedback may be edited prior to publishing. Not all entries will be published. Please view our Terms and Conditions before leaving a comment.