The UC1854L/883BC provides active-power factor correction for power systems that otherwise woulddraw non-sinusoidal current from sinusoidal power lines. This device implements all the controlfunctions necessary to build a power supply capable of optimally using available power-line currentwhile minimizing line-current distortion. To do this, the UC1854L/883BC contains a voltage amplifier, ananalog multiplier and divider, a current amplifier, and a fixed-frequency PWM.
In addition, the UC1854L/883BC contains a power MOSFET-compatible gate driver, 7.5-V reference,line anticipator, load-enable comparator, low-supply detector, and overcurrent comparator.
The UC1854L/883BC uses average current-mode control to accomplish fixed-frequency currentcontrol with stability and low distortion. Unlike peak current-mode, average current controlaccurately maintains sinusoidal line current without slope compensation and with minimal responseto noise transients.
The high reference voltage and high oscillator amplitude of the UC1854L/883BC minimize noisesensitivity while fast PWM elements permit chopping frequencies above 200 kHz. The UC1854L/883BC is usedin single-phase and three-phase systems with line voltages that vary from 75 V to 275 V and linefrequencies across the 50-Hz to 400-Hz range. To reduce the burden on the circuitry that suppliespower to this device, the UC1854L/883BC 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.
Feature
- 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
