The UC1854 provides active-power factor correction for power systems that otherwise would draw non-sinusoidal current from sinusoidal power lines. This device implements all the control functions necessary to build a power supply capable of optimally using available power-line current while minimizing line-current distortion. To do this, the UC1854 contains a voltage amplifier, an analog multiplier and divider, a current amplifier, and a fixed-frequency PWM.
●In addition, the UC1854 contains a power MOSFET-compatible gate driver, 7.5-V reference, line anticipator, load-enable comparator, low-supply detector, and overcurrent comparator.
●The UC1854 uses average current-mode control to accomplish fixed-frequency current control with stability and low distortion. Unlike peak current-mode, average current control accurately maintains sinusoidal line current without slope compensation and with minimal response to noise transients.
●The high reference voltage and high oscillator amplitude of the UC1854 minimize noise sensitivity while fast PWM elements permit chopping frequencies above 200 kHz. The UC1854 is used in single-phase and three-phase systems with line voltages that vary from 75 V to 275 V and line frequencies across the 50-Hz to 400-Hz range. To reduce the burden on the circuitry that supplies power to this device, the UC1854 features low starting supply current.
●These devices are available packaged in 16-pin plastic and ceramic dual in-line packages, and a variety of surface-mount packages.
● Control Boost PWM to 0.99 Power Factor
● Limit Line-Current Distortion to < 5%
● World-Wide Operation Without Switches
● Feedforward Line Regulation
● Average Current-Mode Control
● Low Noise Sensitivity
● Low Startup Supply Current
● Fixed-Frequency PWM Drive
● Low-Offset Analog Multiplier and Divider
● 1-A Totem-Pole Gate Driver
● Precision Voltage Reference
