29
RMX-1000
5
6
7
8
5
6
7
8
A
B
C
D
E
F
5.3 VOLTAGE MONITORING CIRCUIT
Voltage Monitoring
This unit monitors the voltages of the main power-supply ICs, using the FAULT_DET signal.
The DFAULT_DET signal is detected by the K0R UCOM (IC7002) on the P
N
CE Assy. Its level is high (+3.3
V
) during
normal operation but becomes low (0
V
) if any error in voltage is generated.
Product behavior when an error is generated
If power failure is detected with the FAULT_DET signal, the K0R UCOM will stop supplying the DC5
V
power to
DD converters, regulator ICs, setting the FET_S
W
_ADP signal to low and interrupting the FET S
W
(Q1014).
The K0R UCOM also indicates power failure by making the SD-LED flash by sending STB_LED_SEL signal.
Flashing intervals: 250 ms (lit for 125 ms/unlit for 125 ms)
As the DC 5
V
power output is stopped, the indications other than the SD-LED are unlit and all the switches
and
V
Rs are disabled.
Diagnostic procedure
If any voltage is abnormal, that error will be detected by the voltage-monitoring program after it is started after a usual
startup of the unit. Then the DC 5
V
power supply to the DD converters, regulator ICs will be stopped.
Identify which power-supply IC is defective, by turning the unit OFF then back O
N
while monitoring each voltage with an
oscilloscope. Check the value of each voltage immediately before stopping power supply.
Note:
Each time before turning the unit O
N
, make sure that each power-supply IC is not short-circuited to G
N
D.
•
V
+6D
•
V
+3R3D
•
V
+15A
•
V
+5A
•
V
-15A
FET SW
3.3V
Reg IC
AC
adapter
(DC 5 V)
DD
controller
Reg IC
IC7002
K0R UCOM
SD
CARD
Flashing when
an error occurs
Monitoring
FAULT_DET
FET_SW_ADP
N
ormal: Hi level (+3.3
V
)
Abnormal: Low level (0
V
)
N
ormal: Hi level (+3.3
V
)
Abnormal: Low level (0
V
)
At power supply abnormality
detection. FET SW OFF
-> Power supply stop
STB_LED_SEL
Power SW
Always power supply
(Power S
W
: O
N
)
SD-LED
V
oltage
monitoring
circuit
MAIN ASSY
PNCE ASSY
