Power Supply Circuit Description - Toshiba 13A21 Service Manual

4.2 Power Supply Circuit Description

The power supply provides DC electrical power to all the electrical components in the rear projection television.
DVR-4240 also contains Ballast that provides high voltage 380V necessary to strike the lamp when the rear projection
television is powered up. The attached fan draws cooling air through the power supply, as well as through the rest of
the rear projection television.
4.2.1 Location diagram of power board
The power supply consists of the EMI filter, PFC, Standby power, and Main power. The system required voltage is
converted from the Standby and Main power, and the high voltage DC 380V from PFC is applied to the lamp and Main
power.
Line voltage can directly input from 90Vac to 264Vac and boost to 380Vdc for the output, there are common choke
FL1001 and FL1002, and CX1001, CX1002 capacitors to form an EMI filter that can reduce noise and interference.
PFC is main for shaping the AC input line current waveform to correspond to that of the AC input line voltage, and
boost input rectified voltage to 380Vdc for prerequisite.
The output voltage 5Vsb and 5VC are converted from Standby power, when the system is going to the standby mode,
5Vsb is the only output voltage. After the "Power_ON" (CN2002 Pin1) is high, then other voltage outputs are starting
up, otherwise there is only 5Vsb. The 5VC output via Q2006 and under control by 16V depend on Main Power start up,
the other outputs voltage +12V, +16V are converted from Main power. They are the main electrical power for whole
electrical system.
Short circuit protection
All voltage outputs shall have short circuit protection. Only 5Vsb output shall be auto recovery after the short
condition removed.
Over voltage protection
All voltage outputs shall have over voltage protection, 6.24V for 5.25V on 5Vsb outputs; 14.9V for 12V on 12V
outputs; 16V will go follow 12V protection; 415V for 380V output.
Under voltage protection
All voltage outputs shall have under voltage protection, besides +/-20V and 380V outputs (4.12V for 5.1V on 5Vsb
outputs, 9.7V for 12V on 12V outputs.)
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