BD101 is a rectifier in which there are 4 build-in diodes, inverting AC to DC.
CP111 is used to smooth the wave from rectifier. FR101, and FR201 is a fuse resistor to
protect the following circuit when inrush current is too large.
UP101 is a current-mode PWM controller with excellent power-saving operation, the number
of external components and drastically simplifies the PFC implementation .It also integrates high
safety protection features that make the FAN6961SZ a driver for robust and compact PFC stages.
LP102, QP102, DP105 are boost &PFC circuit, It`s boost to 400V.
UP101 is a current-mode PWM controller with excellent power-saving operation, It features a
high-voltage current source to directly supply the startup current from bulk capacitor and further to
provide lossless startup circuit. Max start-up current for UP101 is -1.5mA, When current flow from
the bulk capacitor CP111 through US101 PIN7 to start up US101, Meanwhile, the VCC supply
current is as low as2.5mA thus most of the HV current is utilized to change the VCC capacitor
CS104, When Vcc (Pin5) reaches UVLO(on) threshold ,The US101 is powered on to start issuing
Fig.6
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