Datasheet

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APPLICATION INFORMATION
UCC28019 Operation
UCC28019
SLUS755B – APRIL 2007 – REVISED DECEMBER 2007
The UCC28019 is a switch-mode controller used in boost converters for power factor correction operating at a
fixed frequency in continuous conduction mode. The UCC28019 requires few external components to operate as
an active PFC pre-regulator. Its trimmed oscillator provides a nominal fixed switching frequency of 65 kHz,
ensuring that both the fundamental and second harmonic components of the conducted-EMI noise spectrum are
below the EN55022 conducted-band 150-kHz measurement limit.
Its tightly-trimmed internal 5-V reference voltage provides for accurate output voltage regulation over the typical
world-wide 85 V
AC
to 265 V
AC
mains input range from zero to full output load. The usable system load ranges
from 100 W to 2 kW and may be extended in special situations.
Regulation is accomplished in two loops. The inner current loop shapes the average input current to match the
sinusoidal input voltage under continuous inductor current conditions. Under extremely light load conditions,
depending on the boost inductor value, the inductor current may go discontinuous but still meet Class-D
requirements of IEC 1000-3-2 despite the higher harmonics. The outer voltage loop regulates the output voltage
on VCOMP (dependent upon the line and load conditions) which determines the internal gain parameters for
maintaining a low-distortion steady-state input current waveshape.
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Product Folder Link(s): UCC28019