Chopper Regulator - NEC MultiSync 3D JC-1404HME Service Manual

H.OSC
0519
COMPARATOR
H.OUT
100µ
160V
H.T
.-----1AC
FEEDBACK
REFERENCE
7f7
1-----1
SAWTOOTH VOLTAGE
GENERATOR
n
F.B.T
J L _
DC FEEDBACK
(Fig. 2-1-2b) BLOCK DIAGRAM of Main DC/DC Converter.
(2-1-3) +12V chopper regulator (f)
H.V.
Adj.
This regulator
is PWM
controlled and synchronized with the H.OSC. output of the DC/DC
converter. The regulator's feedback circuit provides a constant and stable output voltage for any
conditions (H.OSC. Frequency and +12V line load variations). If the H.OSC. operation stops, this
output voltage will become low.
The BLOCK DIAGRAM is shown in Fig. 2-1-3.
DRIVE CIRCUIT
FOR OUTPUT FET
H.OSC
SAWTOOTH
GENERATOR
+12V Adj.
(Fig. 2-1-3) BLOCK-DIAGRAM of +12V Regulator.
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