PFC/PWM controller provides higher efficiency in dual-switch flyback topologies

December 16, 2010 // Paul Buckley

Fairchild Semiconductor has introduced an integrated critical mode PFC and quasi-resonant current mode PWM controller that meets regulatory requirements by providing more than 90 percent efficiency and less than 300 mW at no load for increased power savings.

The FAN6920MR combines a power factor correction (PFC) controller and a quasi-resonant PWM controller for a cost effective design that uses fewer external components. The device was developed for power engineers, especially those involved in All-In-One (AIO) PC power, Slim Pack PC adapters, LCD TV and LED lighting designs, that require a dual switch flyback topology to provide the higher efficiency and increased energy savings demanded by government regulations – something that LLC or single flyback solutions cannot provide.

For PFC, the device uses a controlled on-time technique to provide a regulated DC output voltage and to perform natural power factor correction. With an innovative total harmonic distortion (THD) optimizer, the FAN6920MR can reduce input current distortion at zero-crossing duration to improve THD performance.

For PWM control, the FAN6920MR provides several functions to enhance the power system performance including extended valley detect up to the 12th valley cycle for reduced switching frequency, improved light load efficiency, green-mode operation, an internal 10ms soft start and high/low line over-power compensation.

Additionally, the device provides many protection functions including brownout, secondary-side open-loop and over-current with auto recovery, external auto-recovery protection triggering and internal over-temperature shutdown.

Available in a 16-pin small outline package (SOP), the FAN6920MR is ideal for AIO computers, AC/DC netbook adapters (Slim Pack), open-frame SMPS and battery chargers, as well as LCD TV and LED street lights.

Fairchild enables engineers to drive innovation in their designs by developing solutions like the FAN6920MR, which is part of a family of integrated critical mode PFC and quasi-resonant current mode PWM controllers. The devices integrate functionality, increase performance and provide full protection while lowering component counts, simplifying design and reducing bill of material costs.


Availability and Pricing

Samples of the FAN6920MR are available now priced at $00.82 in 1,000 quantity pieces

More information about the FAN6920MR at www.fairchildsemi.com/ds/FA/FAN6920MR.pdf

Visit Fairchild Semiconductor at www.fairchildsemi.com

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