AC step driver for LED bulbs improves line regulation by 2x
The line regulation of the XR46073 is improved by a factor of two compared with Exar’s prior generation.
Exar’s patented AC step driving ICs provides solutions for bulb, tube and downlight applications that do not require the use of inductors, transformers, electrolytic capacitors or metal oxide varistors (MOVs), depending on the specific requirements of the application. This enables customers to eliminate their separate driver circuit board and greatly reduce the total BOM cost for their LED bulbs. In addition, the solutions deliver a high power factor, low THD, high surge immunity, low flicker and dimming capability with a wide range of industry-standard TRIAC dimmers. Exar’s prior generation of AC step drivers is comprised of single step controllers, each controlling an individual current level to the LEDs. The XR46073 integrates two steps of current control to the LED strings, greatly improving the line regulation of the circuit by monitoring the line voltage and adjusting LED drive current proportionally.
Also included in the XR46073 is overvoltage protection and over temperature protection. Unlike some competing solutions, during an over temperature condition, the XR46073 smoothly and continuously reduces current to the LED string, reducing power dissipation in the process, until temperatures have stabilized at an acceptable level.
Availability and Pricing
The XR46073 is available in a RoHS compliant, green/halogen free, space-saving 2 mm x 2 mm DFN package. The XR46073 is priced at $0.29 each in 10,000-piece quantities.