UC2854J

高功率因数前置稳压器 High Power Factor Preregulator

DESCRIPON

The UC3854A/B products are pin compatible enhanced versions of the UC3854. Like the UC3854,

these products provide all of the functions necessary for active power factor corrected preregulators. The controller achieves near unity power factor by shaping the ac input line current waveform to correspond to the ac input line voltage. To do this the UC3854A/B uses average current mode control. Average current mode control maintains stable, low distortion sinusoidal line current without the need for slope compensation, unlike peak current mode control.

FEATURES

• Controls Boost PWM to Near-Unity Power Factor

• Limits Line Current Distortion To <3%

• World-Wide Operation Without Switches

• Accurate Power Limiting

• Fixed-Frequency Average Current-Mode Control

• High Bandwidth 5 MHz, Low-Offset Current Amplifier

• Integrated Current- and Voltage-Amplifier Output Clamps

• Multiplier Improvements: Linearity, 500 mV VAC Offset Eliminates External Resistor, 0 V to 5 V Multout Common-Mode Range

• VREF GOOD Comparator

• Faster and Improved Accuracy ENABLE Comparator

• UVLO Options 16 V/10 V or 10.5 V/10 V

• 300-µA Start-Up Supply Current