High power factor preconditioner

The UC3853 provides simple and high performance active power factor correction. Using the same control technology as the UC1854, the 8-pin device utilizes a simplified architecture and internal oscillator to minimize the number of external components. The UC3853 integrates a precision multiplier/square/divider circuit, voltage and current loop error amplifiers, and a precision voltage reference for average current mode control with RMS line voltage compensation.

This control technique maintains constant loop gain with input voltage variations, thus minimizing input line current distortion within the global input voltage range. The internal 75kHz oscillator includes an external clock input that allows synchronization of the downstream converter. In addition, the device features an overvoltage protection comparator, a clip-on MOSFET gate driver, low self-bias during undervoltage locking, and low start and supply current.

These devices are available in 8-pin plastic and ceramic dual in-line (DIP) packages, as well as 8-pin small profile (SOIC) packages. The UC1853 works from -55°C to +125°C, the UC2853 works from -25°C to +85°C, and the UC3853 works from 0°C to +70°C.

Features

● Complete 8-pin power factor solution
● Reduce external components
● RMS line voltage compensation
● Exact multiplier/square/division
● Internal 75kHz synchronizable oscillator
● Average current mode PWM control
● Over voltage protection comparator
● High current, clamp the door driver