The UC3854N is a High Power Factor Preregulator that 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. To do this, it contains a voltage amplifier, an analogue multiplier/divider, a current amplifier and a fixed-frequency PWM. In addition, the UC3854 contains a power MOSFET compatible gate driver, 7.5V reference, line anticipator, load-enable comparator, low-supply detector and 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.
- Control boost PWM to 0.99 power factor
- Limit line current distortion to <5%
- World-wide operation without switches
- Feed-forward line regulation
- Average current-mode control
- Low noise sensitivity
- Low start-up supply current
- Fixed-frequency PWM drive
- Low-offset analogue multiplier/divider
- 1A Totem-pole gate driver
- Precision voltage reference
- Green product and no Sb/Br
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