Features Control boost power factor PWM to 0.99
Limit line current distortion < 5%
· World operation without switching · Feed-forward profile · Average current mode control · Low noise sensitivity · Low startup supply current · Fixed frequency PWM driver · Low offset analog multiplier/divider · 1A totem pole gate driver ·High precision voltage reference

The UC1854 provides active power factor correction for power systems that would otherwise draw non-sinusoidal currents from sinusoidal power lines. This device implements all control functions to create an optimal use of the existing power supply line current while minimizing line current distortion. To do this, the UC1854 contains a voltage amplifier, analog multiplier/divider, a current amplifier and fixed frequency PWM. Additionally, the UC1854 contains a power MOSFET compatible gate driver, 7.5V reference, line predictor, load, enable comparator, low supply detector, and overcurrent comparator. UC1854 adopts average current mode control to complete fixedfrequency stable and low distortion current control. Unlike peak current mode, average current control can accurately maintain sinusoidal line current with no slope compensation and minimal response to noise transients. The UC1854's high reference voltage and oscillation amplitude reduce noise sensitivity, while the fast PWM element permits chopping frequencies above 200KHz. The UC1854 can be used for single and three line voltages from 75 volts to 275 volts at different stage systems over the entire 50Hz to 400Hz range and line frequency. In order to reduce the burden on the power supply circuit of this device, the UC1854 has a low start-up supply current. These devices are available in 16-pin packages, plastic and ceramic dual in-line packages, and various surface mount packages.