Panasonic KX-NS500UC (serv.man2) Service Manual ▷ View online
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KX-NS500UC
2) 41V Output voltage
2-1) 41V Output
FET Q151 is in ON status during normal operation, conducts to main converter output and the potentiostatically-controlled volt-
age is output.
Q151 is in ON status when the sub winding voltage of coil L201 of 15V output converter has force applied to it.
age is output.
Q151 is in ON status when the sub winding voltage of coil L201 of 15V output converter has force applied to it.
2-2) 41V Output Overcurrent Protection Circuit
This circuit consists mainly of R161, Q152.
When Overcurrent flows to R161, the voltage potential difference of R161 is detected, Q152 is turned ON, and Q151 is turned
OFF.
Consequently the fold back current limiting shuts down 41V output.
When Overcurrent flows to R161, the voltage potential difference of R161 is detected, Q152 is turned ON, and Q151 is turned
OFF.
Consequently the fold back current limiting shuts down 41V output.
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KX-NS500UC
4.9.
Battery voltage input and output
This section describes the operation of battery input and output.
1) Battery voltage output (charge time)
Charge circuit has constant voltage and constant current.
When the battery voltage is high, a controlled fixed voltage of the main converter is output.
When the battery voltage is low, a controlled fixed current of main converter is output.
When the battery switch SW181 turns ON and CN102áB-áC is short circuited, the main converter output supplies voltage with
controlled circuit, and Q181, Q182, Q183 change to ON. The voltage from L201 (sub winding voltage) is applied to the gate ter-
minal of Q161, Q163 and the battery output.
When the battery voltage is low, battery output is limited to a fixed current controlled by R170, R171, R172, and Q162.
When voltage is even lower.
Consequently the fold back current limiting shuts down 41V output.
When the battery voltage is high, a controlled fixed voltage of the main converter is output.
When the battery voltage is low, a controlled fixed current of main converter is output.
When the battery switch SW181 turns ON and CN102áB-áC is short circuited, the main converter output supplies voltage with
controlled circuit, and Q181, Q182, Q183 change to ON. The voltage from L201 (sub winding voltage) is applied to the gate ter-
minal of Q161, Q163 and the battery output.
When the battery voltage is low, battery output is limited to a fixed current controlled by R170, R171, R172, and Q162.
When voltage is even lower.
Consequently the fold back current limiting shuts down 41V output.
2) Battery voltage input (power outage)
Battery voltage conducts to FET Q163 and diode D163, and is supplied by main converter output (C101, C102, C109).
When the battery voltage is reduced, Q181, Q182, Q183 on the battery control circuit go OFF. Q163 of the battery input/output
DC switch circuit goes to OFF status and releases the battery which stops the power supply.
When the battery voltage is reduced, Q181, Q182, Q183 on the battery control circuit go OFF. Q163 of the battery input/output
DC switch circuit goes to OFF status and releases the battery which stops the power supply.
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KX-NS500UC
4.10. Alarm Signal Sending Circuit
This section describes the operation of the circuit that sends the AC alarm/DC alarm signal
1) Alarm Circuit Power Supply
This power supply consists mainly of Q301, D301. The output of the main converter (described in section 2) drops from 41V to
around 26V for a more stable supply.
around 26V for a more stable supply.
2) AC alarm signal sending circuit
When the AC Detection Circuit (described in section 1 (5)) detects AC input as "Yes", the Secondary side transistor of PC80
turns ON. This action turns Q312 ON and then a LOW signal is sent to AC alarm output.
However, if the AC input is detected as "No", the Secondary side transistor of PC80 turns OFF. This action turns Q312 OFF and
then AC alarm sending output becomes OPEN. (Open collector output)
turns ON. This action turns Q312 ON and then a LOW signal is sent to AC alarm output.
However, if the AC input is detected as "No", the Secondary side transistor of PC80 turns OFF. This action turns Q312 OFF and
then AC alarm sending output becomes OPEN. (Open collector output)
3) DC Alarm Signal Sending Circuit
When 41V is output normally, transistors Q303 and Q304 in the output voltage detection circuit turn ON. Q302 also turns on and
then DC alarm sending output becomes LOW.
When 41V output becomes abnormal, transistors Q303 and Q304 turn OFF, Q302 turns OFF and DC alarm sending output
becomes OPEN. (Open collector output)
then DC alarm sending output becomes LOW.
When 41V output becomes abnormal, transistors Q303 and Q304 turn OFF, Q302 turns OFF and DC alarm sending output
becomes OPEN. (Open collector output)
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KX-NS500UC
4.11. Protection Circuit
This section describes the Overvoltage Protection Circuit and Overheat Protection Circuit.
1) Abnormal Condition Detection Circuit
Abnormal condition detection circuit is a thyristor circuit which is comprised of Q306 and Q307. When power supply operation
becomes abnormal, a signal is sent to the abnormal detection circuit and Q307 is turned ON. A current flows through the diode
of PC50, which is sent to the control circuit of main converter. The operation of main converter is then stopped.
becomes abnormal, a signal is sent to the abnormal detection circuit and Q307 is turned ON. A current flows through the diode
of PC50, which is sent to the control circuit of main converter. The operation of main converter is then stopped.
2) Overheat Detection Circuit
When internal temperature of power supply rises abnormally, resistance values of PTC thermistor PT301 increase, transistor
Q305 turns ON, and signal is sent to the abnormal detection circuit through D312.
Q305 turns ON, and signal is sent to the abnormal detection circuit through D312.
3) Overvoltage Protection Circuit
When 15V or 41V output becomes abnormal, that voltage is sent to the abnormal detection circuit through zener diode D311
4) Reverse Connection Protection Circuit
When the battery is connected in reverse, + terminal of the battery becomes negative voltage, D167, D168, D169 start to con-
duct and transistor Q313 turns ON.
Dropper Circuit voltage (in section 5) is sent to the abnormal detection circuit through zener diode D319.
duct and transistor Q313 turns ON.
Dropper Circuit voltage (in section 5) is sent to the abnormal detection circuit through zener diode D319.
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