DESCRIPTION

· The UCC2850x family integrates control functions for active power-factor-corrected preregulators and second-stage DC-to-DC converters.

· Achieves near-unity power factor by shaping AC input line current to match AC input-line voltage using average current-mode control.

· Features peak current-mode control in the DC-to-DC converter for step-down power conversion.

· Includes line feedforward (V FF) to maintain constant input power across varying input voltages.

· Offers over-voltage protection, zero-power detection, and peak current and power limiting in the PFC section.

· Available in 20-pin N and DW packages with various UVLO thresholds for different operational needs.

FEATURES

· Combines PFC and downstream converter controls.

· Controls boost preregulator to achieve near-unity power factor.

· Provides accurate power limiting and improved feedforward line regulation.

· Utilizes peak current-mode control in the second stage with programmable oscillator.

· Features leading-edge/trailing-edge modulation to reduce output ripple.

· Low start-up supply current and synchronized second stage start-up with programmable soft-start.

· Programmable second stage shutdown capability.

APPLICATIONS

· Suitable for power supplies requiring active power factor correction and efficient DC-to-DC conversion.

· Ideal for applications needing consistent power delivery across a wide range of input voltages.

· Used in systems where minimizing output ripple and ensuring stable power output are critical.