Chapter 2 Operating Principles
2-2. Operation of Control Parts
2-23 CL-S400DT
2-2-5. Other circuits
(1) Regulator circuits
The “SA Main PCB” receives +24V from the “SA Power Supply” and produces each voltage.
U18 (DC-DC converter) makes up a +5V regulator, U19 (DC-DC converter) makes up a +3.3V
regulator and U20 (DC-DC converter) makes up +1.5V and +1.2 V regulators.
The DC voltages produced and their purposes are as follows:
+24V: For driving circuits
+5V: For LED and I/F circuits
+3.3V: For logic circuits, etc.
+1.5V: For CPU
+1.2V: For FPGA
If +1.5V for CPU is not produced, Q18 turns OFF and +3.3V for logic circuits is shut off for
safety.
When pin 114 (PWRSAVE) of the CPU (U1A) goes “Low”, Q13 turns OFF and the “SA Power
Supply” enters power saving mode. (Power saving mode is effective if the “Standby Mode”
submenu under the “System Setup” main menu is set to “On”. However, the “Standby Mode” is
set to “Off” at factory default.)
3
4
1
4
5
2
J14
6
7
+24V
+1.5V
+3.3V
[SA Main PCB]
Q13
DTC115EM
U1A
CPU
D18
114
+5V
C109
C108
+
VIN
LX
FB
3
5
2
U18
DC-DC Converter
R1243S100C
VIN
LX
FB
3
5
2
U19
DC-DC Converter
R1243S100C
VIN1
VIN2
LX1
FB1
LX2
FB2
8
4
7
U20
DC-DC Converter
PAM2306APCB
1
2
10
+1.2V
Q18
+3.3V
Q19
+5V Regulator
+3.3V Regulator
+1.5V/+1.2V Regulator
L: Power Saving mode
H: Normal mode
+5V
PWRSAVE
From
SA Power Supply
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