description
the fan7529 is an active power factor correction (pfc)
controller for boost pfc applications that operates in critical
conduction mode (crm). it uses the voltage mode
pwm that compares an internal ramp signal with the
error amplifier output to generate mosfet turn-off signal.
because the voltage-mode crm pfc controller does
not need rectified ac line voltage information, it saves the
power loss of the input voltage sensing network necessary
for the current-mode crm pfc controller.
fan7529 provides many protection functions, such as
over-voltage protection, open-feedback protection, overcurrent
protection, and under-voltage lockout protection.
the fan7529 can be disabled if the inv pin voltage is
lower than 0.45v and the operating current decreases to
65μa. using a new variable on-time control method,
thd is lower than the conventional crm boost pfc ics.