AC Step Driver for LED Bulbs optimizes line regulation.

Press Release Summary:

Supplied in 2 x 2 mm DFN package, XR46073 serves as 2-step LED current controller for AC step driving with optimized line regulation primarily for A19 LED bulb applications. TRIAC-dimmable IC integrates 2 steps of current control to LED strings, improving circuit line regulation by monitoring line voltage and adjusting LED drive current proportionally. Integrating overvoltage and over temperature protection, RoHS-compliant product offers system power regulation over ±10% AC input.

Original Press Release:

Exar AC Step Driver for LED Bulbs Improves Line Regulation by 2x

XR46073 targets A19 LED bulbs with more integrated two-step current controller

Fremont, CA – Exar Corporation (NYSE: EXAR), a leading supplier of high-performance integrated circuits and system solutions, expanded its industry-leading offering of AC step driver solutions for LED bulbs with the introduction of the XR46073. The XR46073 is a two-step LED current controller for AC step driving with improved line regulation primarily for A19 LED bulb applications. The line regulation of the XR46073 is improved by a factor of two over Exar’s prior generation.

Exar’s patented AC step driving ICs provide industry-leading 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, these solutions deliver a very high power factor, very 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.

“The XR46073 is a terrific addition to our world leading AC step driving solutions for the bulb market,” said Steve Bakos, Exar’s vice president, lighting and display products. “Its high level of integration and improved line regulation allow our customers to hit extremely aggressive price points while delivering the performance required for the majority of the worldwide markets.”

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.

The XR46073 is available in a RoHS compliant, green/halogen free, space-saving 2mm x 2mm DFN package. The XR46073 is priced at $0.29 each in 10,000-piece quantities. For more information, visit

Summary of features:


- Integrated two-step LED current control

- Excellent system power regulation over ±10% AC input

- -6V to 78V chip supply voltage range

- Over temperature and voltage protection

- 6-lead DFN package


- All solid state components

- Single board LED lighting solution available

- No electrolytic capacitor required

- Scalable architecture allows optimization of performance vs. cost

- High PF and Low THD performance

- Flexible PCB layout options

- TRIAC dimmable

About Exar

Exar Corporation designs, develops and markets high performance integrated circuits and system solutions for the industrial and embedded systems communications, high-end consumer and infrastructure markets. Exar's broad product portfolio includes analog, display, LED lighting, mixed-signal, power management, connectivity, data management and video processing solutions. Exar has locations worldwide providing real-time customer support.  For more information, visit

Exar, XR, the Exar logo are registered trademarks and PowerArchitect is a trademark of Exar Corporation. All other trademarks are the property of their respective owners.

Press Contacts:

Rhoeda Farolan

Senior Manager, Corporate Marketing


Bob Jones or Derek Rye


North America: 408-786-5151

Europe: +44 1225 470000

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