Circuit Operation Theory - BenQ M2700HD Service Manual

5.5 Circuit Operation Theory

Operation theory
AC Current Input Circuit
P801 is a connector for connecting AC Power. F801 is a fuse to protect all the circuit. AC input voltage
is from 90v to 264V. R801 and R802 joined between two inputting main circuit to prevent man from
shock.D808 rectify AC in put to DC voltage, L801, L806,L803, C801, c802, C803, C804 ,c813, c814 formed
a low frequency filter net for EMI and EMC.
High Voltage to Low Voltage Control Circuit
C807 is used to smooth the wave from rectifier. IC806 is a highly integrated PWM controller. When
rectified DC high voltage is applied to the HV pin during start-up, the MOSFET Q803 is initially off befor the
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