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Highly-Integrated Green-Mode PWM Controller
New product
http://www.fairchildsemi.com/pf/SG/SG6903.html -
Green-Mode PFC / Forward PWM Controller
The highly integrated SG6932 is designed for power supplies with boost PFC and forward PWM.
Features overview
- Innovative switching-charge multiplier-divider
- Interleaved PFC / PWM switching
- PFC over-voltage and under-voltage protections
- PFC and PWM feedback open-loop protection
- Cycle-by-cycle current limiting for PFC/PWM
- Selectable PWM maximum duty cycle 50% and 65%
- Brownout protection
- Green-mode PFC and PWM operation
- Multi-vector control for improved PFC output transient response
- Low operating current
- Average-current-mode for input-current shaping
- Slope compensation for PWM
- Power-on sequence control and soft-start
Applications
- PC-ATX power supplies
- Switch-mode power supplies with active PFC
- Servo system power supplies
http://www.fairchildsemi.com/ds/SG%2FSG6932.pdf -
A "bridgeless P.F.C. configuration" based on L4981 P.F.C. controller
This technical document describes an innovative topology dedicated to a medium to high power PFC stage. The originality of this topology is the absence of the bridge that usually is placed between the EMC filter and the PFC stage. The advantages of this topology can be found in terms of increased efficiency and improved thermal management.
http://www.st.com/stonline/products/literature/an/9119.pdf -
Circuits for power factor correction with regards to mains filtering
The new European Norms EN 60555 and the international standard IEC555 will impose a limit on the harmonic content of the input current of mains supplied equipment. In practice this will require the addition of a Power Factor Corrector (PFC) at the input of many types of mains operated electronic equipment, for example electronic lamp ballasts, motor drives and TV power supplies. A correctly designed PFC draws a sinusoidal input current from the mains supply, in phase with the mains voltage, and meets the EN60555 norm. It may also provide additional functions, such as automatic mains voltage selection and a regulation of the voltage supplied to the attached equipment.
http://www.st.com/stonline/products/literature/an/3727.pdf -
A 500W high power factor with the L4981A continuous mode IC
The widespread use of passive AC/DC off-line converters causes low power factor and high line current harmonic distortion. To reduce these phenomena and to comply with relevant regulatory agency requirements, designers are employing active power factor correction in their off-line SMPS applications. This paper describes a practical, low cost and easy to implement 500W power factor corrected application that employs the L4981A Continuous Mode PFC IC.
http://www.st.com/stonline/products/literature/an/4046.pdf
