Furuno NX-700B Service Manual page 82

Power supply block
The input voltage of +12 VDC to +24 VDC is converted to +18 VDC, +12 VDC, +5
VDC and +3.3 VDC on the switching power supply circuit. The main specifications
are as follows.
Item
Input power supply
voltage range
Switching frequency
Conversion efficiency
+12 VDC output
+3.3 VDC output
+5 VDC output
+18 VDC output
Output protection
Input reverse
connection protection
circuit
Input low-voltage
protection
Input over-voltage
protection
Power fail signal output
L4, C63/62, 68
DC INPUT
DC+
Line FIL
DC-
Power SW
Table 5.3.3 Specifications of Power supply block
Specifications
+10.8 VDC to +31.2 VDC
192 kHz + 10 kHz
65 % or more (at max load)
+12 VDC + 0.6 V, 100～300 mA
+3.3 VDC + 0.2 V, 50～200 mA
+5 VDC + 0.2 V, 50～150 mA
+18 VDC + 1 V, 0～80 mA
Over-current protection: 780 mA to 1300 mA
Provided, Protected by fuse
(F401: 2A at CR401 of the receiver unit.)
Provided, Operated at +7 VDC to +9 VDC
Provided, Operated at +34 VDC to +38 VDC
Detects power failure from +3.3 VDC output
voltage. Time of 1.5 ms or more is assured for
voltage drop from +3.3 VDC to +3.0 VDC.
Q13
SW
U24
TP1
DET
Over &
Low Volt
CR18,
Q14
Q15
Vcc
10V
Driver
AVR
Q12,
C81
E1,2
Soft
Vcc IN2
Start
Vcc
Vcc
TP2
C74
DC-
Fig. 5.3.5 Block Diagram: Power supply block
CR12
T1
C59
CR11
C65
CR15
C66
Q11, CR14
CR16
5V AVR
U27
U20
DET
IN1
PWM
MB3759PF
DTC
CT RT
R106
5-11
5.3 Block Description
Remarks
Adjusted at R106
Output adjusted at R79
Not adjusted
Not adjusted
Not adjusted
Detected at
R71-73, 109 and 110
Detected at U24
Detected at U24
U18
18V AVR
L3
C55
3.3V AVR
L2
C54
U12
R109,110
PF DET
R71-73
U25, 23
DCV
DET
R79
+18V
+12V
+5V
+3.3V
Q8
PF