高功率因数前置稳压器 High Power Factor Preregulator
DESCRIPON
The UC1854 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, the UC1854 contains a voltage amplifier, an analog multiplier/divider, a current amplifier, and a fixed-frequency PWM. In addition, the UC1854 contains a power MOSFET compatible gate driver, 7.5V reference, line anticipator, load-enable comparator, low-supply detector,and over-current comparator.
FEATURES
• 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 Analog Multiplier/Divider
• 1A Totem-Pole Gate Driver
• Precision Voltage Reference