UCC2854

Features:

 ·Provides Control of PFC and PWM Power Stages In One Device
 ·Leading-Edge PFC, Trailing-Edge PWM Modulation for Reduced Ripple
 ·Built-In Sequencing of PFC and PWM Turn-On
 · 2-A Source and 3-A Sink Gate Drive for Both PFC and PWM Stages
 ·Typical 16-ns Rise Time and 7-ns Fall Time into 1-nF Loads
 ·PFC Features
    − Average-Current-Mode Control for Continuous Conduction Mode Operation
    − Highly-Linear Multiplier for Near-Unity Power Factor
    − Input Voltage Feedforward Implementation
    − Improved Load Transient Response
    − Accurate Power Limiting
    − Zero Power Detect PWM Features
    − Peak-Current-Mode Control Operation
    − 1:1 or 1:2 PFC:PWM Frequency Options
    − Programmable maximum duty cycle
    − Programmable Soft-Start
    − Two Hysteresis Options for Differing Hold-Up Time Requirements


Description

The UCC28510 series of combination PFC/PWM controllers provide complete control functionality for any off-line power system requiring compliance with the IEC1000−3−2 harmonic reduction requirements. By combining the control and drive signals for the PFC and the PWM stages into a single device, significant performance and cost benefits are gained. By managing the modulation mechanisms of the two stages (leading-edge modulation for PFC and trailing-edge modulation for PWM), the ripple current in the boost capacitor is minimized.

Based on the average current mode control architecture with input voltage feedforward of prior PFC/PWM combination controllers, these devices offer performance advantages. Two new key PWM features are programmable maximum duty cycle and the 2x PWM frequency options to the base PFC frequency. For the PFC stage, the devices feature an improved multiplier and the use of a transconductance amplifier for enhanced transient response.