5-7
Samsung Electronics
5-9 SMPS
This Switching Mode Power Supply (SMPS) rectifies AC85~135V (57~63Hz) and su5V, +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.
Figure 5-11 SMPS Block Diagram
AC
INPUT
AC120V
60Hz
LINE
FILTER
LAMP
CONTROL
CIRCUIT
TO
LAMP
LAMP CONTROL
SIGNAL INPUT
START
UP
VOLTAGE CONTROL
AND
DRIVE CIRCUIT
BRIDGE
RECTIFIER
SNUBBER
CIRCUIT
OUTPUT
SMOOTHING
CIRCUIT
VOLTAGE
DETECTOR
CIRCUIT
Circuit Description