UC3852N Datasheet PDF - TI

●High Power-Factor Preregulator

●DESCRIPTION

●The UC1852 provides a low-cost solution to active power-factor correction (PFC) for systems that would otherwise draw high peak current pulses from AC power lines. This circuit implements zero-current switched boost conversion, producing sinusoidal input currents with a minimum of external components, while keeping peak current substantially below that of fully-discontinuous converters.

●The UC1852 provides controlled switch on-time to regulate the output bulk DC voltage, an off-time defined by the boost inductor, and a zero-current sensing circuit to reactivate the switch cycle. Even though switching frequency varies with both load and instantaneous line voltage, it can be maintained within a reasonable range to minimize noise generation.

●FEATURES

●• Low-Cost Power Factor Correction

●• Power Factor Greater Than 0.99

●• Few External Parts Required

●• Controlled On-Time Boost PWM

●• Zero-Current Switching

●• Limited Peak Current

●• Min and Max Frequency Limits

●• Starting Current Less Than 1mA

●• High-Current FET Drive Output

●• Under-Voltage Lockout