The UCC28180 is a flexible and easy-to-use, 8-pin, active Power-Factor Correction (PFC) controller that operates under Continuous Conduction Mode (CCM) to achieve high Power Factor, low current distortion and excellent voltage regulation of boost pre-regulators in AC - DC front-ends. The controller is suitable for universal AC input systems operating in 100-W to few-kW range with the switching frequency programmable between 18 kHz to 250 kHz, to conveniently support both power MOSFET and IGBT switches. An integrated 1.5-A and 2-A (SRC-SNK) peak gate drive output, clamped internally at 15.2 V (typical), enables fast turn-on, turn-off, and easy management of the external power switch without the need for buffer circuits.
Low-distortion wave shaping of the input current using average current mode control is achieved without input line sensing, reducing the external component count. In addition, the controller features reduced current sense thresholds to facilitate the use of small-value shunt resistors for reduced power dissipation, especially important in high-power systems. To enable low current distortion, the controller also features trimmed internal current loop regulation circuits for eliminating associated inaccuracies.
Simple external networks allow for flexible compensation of the current and voltage control loops. In addition, UCC28180 offers an enhanced dynamic response circuit that is based on the voltage feedback signal to deliver improved response under fast load transients, both for output overvoltage and undervoltage conditions. An unique VCOMP discharge circuit provided in UCC28180 is activated whenever the voltage feedback signal exceeds VOVP_L thus allowing a chance for the control loop to stabilize quickly and avoid encountering the overvoltage protection function when PWM shutoff can often cause audible noise. Controlled soft start gradually regulates the input current during start-up and reduces stress on the power switches. Numerous system-level protection features available in the controller include VCC UVLO, peak current limit, soft overcurrent, output open-loop detection, output overvoltage protection and open-pin detection (VISNS). A trimmed internal reference provides accurate protection thresholds and regulation set-point. The user can control low-power standby mode by pulling the VSENSE pin below 0.82 V.
