Other Circuits; Power Supply Circuit - Citizen CL-S6621 Technical Manual

Operation of Control Parts

2-2-5. Other circuits

(1) Power supply circuit

The "SA, Main PCB" receives +24V from the "Unit, Power Supply" and produces each DC
power.
U22, U24 and U23 are DC-DC converter ICs to produce +5V, +3.3V and +1.5V/+1.2V from
+24V, respectively.
The DC power produced and their purposes are as follows:
+24V: For driving circuits
+5V: For transparent/reflective circuit, "SA, Ribbon PCB", optional I/F, etc.
+3.3V: For logic circuits, LED, etc.
+1.5V: For U1 (CPU)
+1.2V: For U14 (FPGA)
If +1.5V for CPU is not produced, Q22 turns OFF and +3.3V for logic circuits is shut off for
safety.
When pin 114 (PWRSAVE) of U1A (CPU) goes "Low", Q19 turns OFF and the "Unit, Power
Supply" enters Power Saving mode.
In Power Saving mode, the DC output from the "Unit, Power Supply" is changed over from
+24V to approx. +9V.
(Power saving mode is effective if the "Standby Mode" submenu under the "System Setup"
main menu is set to "On". However, it is set to "Off" at factory default.)
J15
9
8
7
6
From
5
Unit, Power
4
Supply 4
3
2
1
CL-S6621
Q19
DTC115EM
+24V
+
C105 C106
[SA, Main PCB]
L: Power Saving mode
H: Normal mode
+5V Regulator
U22
DC-DC Converter
2
3
VIN LX
5
FB
R1243S001C
U24
DC-DC Converter
10
13
PVIN1 SW1
11
14
PVIN2
SW2
15
12
PVIN3 SW3
4
9
VIN
FB
PAM2307AJEADJR
+3.3V Regulator
2-36
U1A
CPU
PWRSAVE
D18
114
+5V
+5V
+1.5V/+1.2V Regulator
U23
DC-DC Converter
+3.3V
7
8
VIN1 LX1
4
FB1
2
1
VIN2 LX2
10
FB2
PAM2306AYPCB
Q22
Q23
+1.5V
+1.2V
+3.3V