patent - 1 Patent umber: 6,545,237 Ashwinkrishnan Hariharan...

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1 Ashwinkrishnan Hariharan and Abilash Ethanur Thuppale POWER FACTOR CORRECTIO& USI&G UC 3854 Inventor: Ashwin Krishnan Hariharan and Abilash Ethanur Thuppale App. No: 09/234,234 Filed: May 4 ,2009 References cited: US PATE&T DOCUME&TS 3,350,370 9/1970 Yamachi et al. . 4,683,529 11/1986 Bucher,II 4,193,111 3/1980 wester 4,317,076 2/1982 Price 5,986,901 11/1999 weng 6,128,205 10/2000 Bernd et al. ABSTRACT: A 250 W Pre-regulator for the purpose of supplying constant output power at a voltage of 380V is designed using a UC3854 IC chip that can change the power factor of an input. T he UC3854 chip provides active power factor correction for power systems that otherwise would draw non-sinusoidal current from sinusoidal power lines. This device implements all the control functions necessary to build a power supply capable of optimally using available power-line current while minimizing line- current distortion. In addition, the UC1854 contains a power MOSFET compatible gate driver, line anticipator, load-enable comparator, low-supply detector, an over-current comparator. The UC3854 uses average current-mode control to accomplish fixed frequency current control with stability and low distortion. Unlike peak current-mode, average current control accurately maintains sinusoidal line current without slope compensation and with minimal response to noise transients. The UC3854's high reference voltage and high oscillator amplitude minimize noise sensitivity while fast PWM elements Patent &umber: 6,545,237 Date of patent: MAY.6,2009 permit chopping frequencies above 200kHz. The UC3854 can be used in single and three phase systems with line voltages that vary from 75 to 275 volts and line frequencies across the 50Hz to 400Hz range. To reduce the burden on the circuitry that supplies power to this device, the UC3854 features low starting supply current. This device is available packaged in 16-pin plastic and ceramic dual in-line packages, and a variety of surface-mount packages. The 250 W pre-regulator designed with the above circuit rectifies the 80V to 270V AC input to DC and then boosted to the 380V DC circuit that can be used to supply the power for use. Then the rectified input is taken in the current and voltage form and fed to the UC 3854 chip inputs along with a reference voltage of zero volts. The power factor of the current is reduced and a constant output power factor of 0.999 is got along with a THD of only 3.81%. Thus, a Power Supply or PSU that is capable of giving a constant output of 380V DC and 250W of power factor 0.999 and THD of 3.81% from an input supply voltage of 80V to 270V AC supply creation a pre-regulator that can regulate the supply to a constant output without distortion. UC3854 Controlled Power Factor Correction Circuit Background of invention: 1. Field of invention: This invention relates to power factor correction controller with a design of a boost preregulator.
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This note was uploaded on 02/04/2011 for the course EE 587 taught by Professor Dr.mohammedsafiuddin during the Spring '11 term at SUNY Buffalo.

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patent - 1 Patent umber: 6,545,237 Ashwinkrishnan Hariharan...

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