Samsung SF6500 Service Manual page 76

5-9 SMPS
This Switching Mode Power Supply (SMPS) rectifies AC85~135V (57~63Hz) and supplies +5V, +12V, -12V,
+24V DC voltages to the circuits in the machine.
This SMPS circuit is divided as follows:
¥ Input stage : This stage consists of AC input, line filter, bridge rectifier.
¥ Converter stage : This stage consists of start up, snubber circuit, voltage control, drive circuit.
¥ Output stage : Output smoothing circuit.
¥ Voltage detector circuit : This circuit detects the output voltage and feeds it back to the converter stage.
¥ Lamp voltage control circuit.
AC
INPUT
AC120V
60Hz
TO
LAMP
LAMP
CONTROL
CIRCUIT
LAMP CONTROL
SIGNAL INPUT
Samsung Electronics
LINE
BRIDGE
FILTER
RECTIFIER
VOLTAGE CONTROL
Figure 5-11 SMPS Block Diagram
SNUBBER
CIRCUIT
START
UP
AND
DRIVE CIRCUIT
Circuit Description
OUTPUT
SMOOTHING
CIRCUIT
VOLTAGE
DETECTOR
CIRCUIT
5-7