Sony RM-PJM50, Manual

Page: 67 / 178

4-7
VPL-FX50
4-4-1-3. Operations of circuit power supply
IC1200 controls a circuit power supply.
(1) Initialization
When stand-by, DC voltage is input to IC1200 pin
1
(VD terminal) driving internal drain
.
kick function of
this IC. In this result, current is supplied each to pin
8
(VC1) and
0
(VC2 driver power source).
When VC1 voltage reaches 15V or over, while VC2
does 10V or over, IC1200 starts oscillation and drives
both the switching-use MOS FET Q1201 and Q1200.
By this, pulse voltage is generated between pin
!=
and
![
of the transformer T1200 and VCC (19
±
1.0 V)is
supplied to IC pin
8
(VC1) with the Diode D1207
and smoothing operation of the smoothing capacitor
C1212.
This VCC subsequently drives the switching-use
MOS-FET Q1201 and Q1200.
In turn, when VC1 and VC2 is lower than 8.4 V and
6.8 V correspondingly, IC1200 ceases operations.
Multiplier Input
GND
Vref
1.8V
1.5V
Multiplier
Delay
Timer R
16V
13V
UVLO
RS Latch
Current Sence Comparator
Over Voltage Comparator
Differential Amp
Voltage Input Fly-back
Compensation
Current sence Input
Drive Output
Zero Current Detector
V
CC
Quick Start
6.7V
1.2V
1.6V
Zero Current
Detector
2.5V
Reference
Voltage
Source
Fig.4 IC1000 Simple Block Diagram