Four-Channel Constant Current LED Drivers
- Wednesday, 27 October 2010
Allegro MicroSystems (Worcester, MA) offers constant current LED drivers to address requirements of internal and external illumination applications within the automotive market. Allegro’s A6261/A6262/A6264 LED drivers offer four channels of up to 100 mA LED current each, and can be paralleled for higher currents.
The drivers operate with a low dropout voltage to minimize power dissipation, and do not require any ballast resistors. The user-selected current is provided to four outputs with each output equally sharing the load. The A6261/62/64 family features short to ground protection, which disables the shorted channel allowing the others to continue to operate. Open LED on any channel is also detected.
The drivers also feature a unique current foldback circuit, which uses the chip junction temperature in order to foldback the LED current and to protect the IC and LEDs (if mounted in proximity and on the same substrate). Key automotive applications include (exterior) brake, turn, tail, and rear combination lighting (RCL), as well as (interior) dome, map, and puddle lighting.