The UC1854 provides active power factor correction for power systemsthat otherwise would draw non-sinusoidal current from sinusoidalpower lines. This device implements all the control functionsnecessary to build a power supply capable of optimally using availablepower-line current while minimizing line-current distortion. To do this,the UC1854 contains a voltage amplifier, an analog multiplier/divider,a current amplifier, and a fixed-frequency PWM. In addition, theUC1854 contains a power MOSFET compatible gate driver, 7.5V reference,line anticipator, load-enable comparator, low-supply detector,and over-current comparator.The UC1854 uses average current-mode control to accomplish fixedfrequencycurrent control with stability and low distortion. Unlike peakcurrent-mode, average current control accurately maintains sinusoidalline current without slope compensation and with minimal response tonoise transients.The UC1854’s high reference voltage and high oscillator amplitudeminimize noise sensitivity while fast PWM elements permit choppingfrequencies above 200kHz. The UC1854 can be used in single andthree phase systems with line voltages that vary from 75 to 275 voltsand line frequencies across the 50Hz to 400Hz range. To reduce theburden on the circuitry that supplies power to this device, the UC1854features low starting supply current.These devices are available packaged in 16-pin plastic and ceramicdual in-line packages, and a variety of surface-mount packages.