Allegro introduced what it says the world’s first LED driver chip that features an integrated Hall-effect switch and requires only two passive components with one or more LEDs to form a complete lighting solution that is small, flexible, rugged, and reliable. The A1569 is targeted at consumer electronics, white goods, boats, RVs, motorcycles, and interior and auxiliary automotive lighting applications.
The new LED driver is a highly integrated solution with a linear, programmable current regulator which provides up to 150mA to drive one or more LEDs. A single silicon chip integrates: a Hall plate, a small-signal amplifier, chopper stabilization, a Schmitt trigger, and a LED driver with soft on/off and short circuit and thermal protection with automatic recovery.
The integrated solid-state Hall-effect switch improves upon failure-prone mechanical switches by supporting silent, sealed and contactless activation. An optional external capacitor programs the turn-on/turn-off rate, adding an elegant “theater” effect. It is controlled by the Hall-effect switch and turns on and off in response to a magnet.
Omnipolar operation and high magnetic sensitivity of the Hall-effect switch make the device tolerant of large air gaps and mechanical misalignment. The device’s on-board regulator permits operation with supply voltages of 7 to 24 V.
Reliability and EMC performance is improved with reverse-battery protection, thermal foldback, and automatic shutdown for thermal overload and shorts to ground. The A1569 prevents damage to the system by removing LED drive current until the short is removed and/or the chip temperature has reduced below the thermal threshold. The driver output is slew-rate-limited to reduce electrical noise during operation.
The device is available in two versions: the ‘K’ option is an automotive-grade (AEC-Q100) device that operates from –40°C to +125°C. The “E” option is for industrial and consumer applications that operate from –40°C to 85°C. Both versions feature a RoHS-compliant, thermally enhanced SOIC-8 surface-mount package.
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