22
DJS-1000
1
2
3
4
A
B
C
D
E
F
1
2
3
4
5.3 VOLTAGE MONITORING CIRCUIT
With this product, voltage of main power supply is monitored by FAULT_DET signal.
In the normal status, FAULT_DET signal is Hi level (+
3
.
3
V), however, in the abnormal status, it is at Low level (0V)
and it is detected by M1 UCOM (IC
8
005).
Voltage monitoring
If power supply failure is detected by FAULT_DET signal, M1 UCOM sets V +12
S
W_CONT signal to Low to stop V+12
S
W and V+12A
power supply output that is outputted from
S
W power supply.
WAKE UP indicator blinks in red.
To stop V+12
S
W and V+12A power supply output, all indications other than WAKE UP are turned OFF and all of
S
W and VR become
unresponsive.
Symptom of product in abnormal status
If the voltage is abnormal, an error is detected when the voltage monitoring program starts operating after usual startup to stop V+12
S
W
and V+12A power supply output that is outputted from
S
W power supply.
Thus, power supply is turned ON for approximately five second at the startup. While monitoring each voltage using an oscilloscope,
turn OFF and ON the power supply and check which voltage is abnormal for the voltages immediately before power supply is stopped.
* Be sure to check the part between each power supply and GND does not cause short-circuit before turning ON the power supply again.
Diagnosis method
Voltage monitoring circuit
Voltage monitoring voltage value
AUDB A
SS
Y
MAIN A
SS
Y
MAIN A
SS
Y
AUDB A
SS
Y
PADB A
SS
Y
LCDB A
SS
Y
•
Regulator
•
DC-DC Converter
•
Regulator
•
DC-DC Converter
•
FET
S
W
•
DC-DC
Converter
•
Regulator
S
W POWER
S
UPPLY
Power Supply
Threshold value
–
+
V+5R1D
4.19V
6.61V
V+4R2D
-
8
.
8
0V
V+
3
R
3
D
2.40V
4.1
8
V
V+OPA
6.4
8
V
-
V-OPA
–5.
8
5V
-
V+9HP
3
.44V
-
V-9HP
–5.
8
5V
-
V+5A
-
6.5
3
V
V+5A_REF
-
6.5
3
V
V+
3
R
3
A
-
4.62V
V+
3
R
3
D_CLK
-
4.62V
Regardless of power switch ON/OFF
always output at AC IN
Hi : Normal
Low : Abnormal
Hi : V+12
S
W, V+12A output
Low : V+12
S
W, V+12A output stop
Monitoring
Hi : Normal
Low : Abnormal
Voltage Monitoring
Circut
Monitoring
Voltage Monitoring
Circut
Monitoring
Monitoring
Monitoring
Monitoring
Blinking abnormal STATUS
(red)
