Constant-current LED Driver
Wed, 10/17/2007 - 6:36am
Allegro MicroSystems, Inc. introduces a three-channel constant-current LED driver with an on-chip oscillator for simple programmable brightness control. It is typically used to drive a cluster of red/green/blue (RGB) LEDs for one pixel in a large display or a lighting fixture. It precisely controls LED brightness via 10-bit pulse-width modulation (PWM) per channel, complemented by 7-bit analog current control per channel to adjust color balance. Allegro’s A6281 drives up to 150 mA per channel and operates from a supply voltage of up to 17 V. Applications include large video displays and signs and architectural and decorative lighting. The maximum supply voltage of 17 V allows series strings of up to four or more LEDs on each output. An on-chip voltage regulator supplies the internal logic and reduces the number of external components and connections.