Voltage Monitoring Circuit - PIONEER DJ TSP-16 Service Manual

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5.3 VOLTAGE MONITORING CIRCUIT

Voltage monitoring
With this product, voltage of main power supply is monitored by FAULT_DET signal.
A
In the normal status, FAULT_DET signal is Hi level (+3.3V), however, in the abnormal status, it is at Low level (0V)
and it is detected by M1 UCOM (IC8005).
Symptom of product in abnormal status
If power supply failure is detected by FAULT_DET signal, M1 UCOM sets V +12SW_CONT signal to Low to stop V+12SW power supply
output that is supplied from AC adapter (DWR1553) via FET (Q209).
Moreover, M1 UCOM displays that power supply abnormal is occurring by blinking MAKE UP button by LED_STBY signal.
To stop V+12SW power supply output, all indications other than WAKE UP are turned OFF and all of SW and VR become unresponsive.
Diagnosis method
If the voltage is abnormal, an error is detected when the voltage monitoring program starts operating after usual startup to stop V+12SW
power supply output that is supplied from AC adapter (DWR1553) via FET (Q209).
Thus, power supply is turned ON for approximately one 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.
B
* Be sure to check the part between each power supply and GND does not cause short-circuit before turning ON the power supply again.
C
V+12E
AC ADAPTER
(DWR1553)
Voltage monitoring circuit
IO ASSY
D
Voltage monitoring voltage value
E
Overpower /
reduced
Power supply
power
+
V+5R1D
-
+
V+4R2D
-
+
V+3R3D
-
V+OPA -
V-OPA -
V+5A +
V+5A_REF +
V+3R3A +
F
+ overpower, - reduced power
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MAIN ASSY
• DC-DC
Converter Monitoring
V+5R1D
Voltage
• Regulator
V+4R2D
monitoring circuit
• FET SW
V+3R3D
FAULT_DET
Hi :
Normal
Low : Abnormal
Hi : V+12SW
output
Low : V+12SW
output stop
V+12SW_CONT
FET
(Q209)
LDO LDO
(IC200) (IC203)
Always output at DC IN
MAIN ASSY
Threshold value
Detection range Center
considering variability value
6.08V to 7.17V 6.61V
3.97V to 4.41V 4.19V
4.88V to 5.08V 4.98V
2.84V to 3.51V 3.17V
4.10V to 4.26V 4.18V
2.31V to 2.50V 2.40V
5.96V to 7.03V 6.48V
-4.77V to -7.17V -5.85V
6.25V to 6.82V 6.53V
6.25V to 6.82V 6.53V
4.05V to 5.23V 4.62V
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3
IO ASSY
Voltage
monitoring circuit
PADB ASSY
LED_STBY
M1 UCOM
(IC8005)
V+3R3E
Case when the monitoring functions
IC201 IN/OUT short-circuit or short-circuit with different power supply
Short-circuit with GND or different power supply
IC202 IN/OUT short-circuit or short-circuit with different power supply
Short-circuit with GND or different power supply
Short-circuit with different power supply
Short-circuit with GND or different power supply
Short-circuit with GND or different power supply
Short-circuit with GND or different power supply
IC5005 IN/OUT short-circuit or short-circuit with different power supply
IC5007 IN/OUT short-circuit or short-circuit with different power supply
IC5006 IN/OUT short-circuit or short-circuit with different power supply
TSP-16
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4
Regulator
V+OPA
Monitoring
V+5A
V+5A_REF
V+3R3A
V-OPA
STBY ASSY
WAKE UP
LED
(D9201)
Blinking in abnormal
status (red)
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