The MC33368 is an active power factor controller that functions as a
boost preconverter in off?line power supply applications. MC33368 is
optimized for low power, high density power supplies requiring a
minimum board area, reduced component count and low power
dissipation. The narrow body SOIC package provides a small
footprint. Integration of the high voltage startup saves approximately
0.7 W of power compared to resistor bootstrapped circuits.
The MC33368 features a watchdog timer to initiate output
switching, a one quadrant multiplier to force the line current to follow
the instantaneous line voltage a zero current detector to ensure critical
conduction operation, a transconductance error amplifier, a current
sensing comparator, a 5.0 V reference, an undervoltage lockout
(UVLO) circuit which monitors the VCC supply voltage and a CMOS
driver for driving MOSFETs. The MC33368 also includes a
programmable output switching frequency clamp. Protection features
include an output overvoltage comparator to minimize overshoot, a
restart delay timer and cycle?by?cycle current limiting.
Features
? Lossless Off?Line Startup
? Output Overvoltage Comparator
? Leading Edge Blanking (LEB) for Noise Immunity
? Watchdog Timer to Initiate Switching
? Restart Delay Timer
? Pb?Free Packages are Available*