IL34262
<Design Equations>
APPLICATION INFORMATION
The application circuits shown in Figures 1, 2 and 3
reveal that few external components are required for a
complete power factor preconverter. Each circuit is a
peak detecting current-mode boost converter that
operates in critical conduction mode with a fixed on-time
and variable off-time. A major benefit of critical
conduction operation is that the current loop is inherently
stable, thus elimination the need for ramp compensation.
The application in Figure 1 operates over an input
voltage range if 90 Vac to 138 Vac and provides an
output power of 80W (230V at 350mA) with an
associated power factor of approximately 0.998 at
nominal line. Figures 2 and 3 are universal input
preconverter examples that operate over a continuous
input voltage range of 90 Vac to 268Vac. Figure 2
provides an output power of 175W (400V at 440mA)
while Figure 3 provides 450W (400V at 1.125A). Both
circuits have an observed worst-case power factor of
approximately 0.989.
2011, February, Rev. 01
IKSEMICON [ IK SEMICON CO., LTD ]
