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KX-TES824RU / KX-TEM824RU
1.4.
CIRCUIT OPERATION
1.4.1.
POWER SUPPY CIRCUIT (PSLP1278YA)
Change from the Original Service Manual Section 11.1
1.4.1.1.
The function of the power unit are listed below
1.4.1.2.
Control Section
1) AC-DC Inverter Function
The AC input voltage is rectified and smoothed by D10-13 and C5. The obtained DC voltage is converted into a rectangular wave by
the switching transistor Q1, then isolated and transduced by T1. This converted rectangular wave is rectified and smoothed by
D101 and C101 to output DC27V. The DC27V is transmitted to the primary side by PC1 and then PWM- controlled to keep con-
stant. The switching frequency of Q1 is approximately 63KHz (55KHz~70KHz).
2) DC-DC Inverter Function
The DC27V as input is converted into a rectangular wave by the switching transistor Q201, then isolated and transduced by T2.
DC+15V, -15V and 3.3V are outputted by a rectification smoothing circuit composed of D401, D301, D701, C401, C301 and C702.
The +3.3V of the three outputs is PWM-controlled by IC201 to keep constant.The switching frequency of the Q2 is approx. 55 KHz.
3) Ringing signal output function
Ringing signal (20/25Hz, 75Vac from main board) is amplified in power by power amplifier circuits (including of IC501, R601~R608,
C601~C603).
Ringing signal amplified in power is transmitted to the ringing transformer through pin 4 of CN601.
4) Battery back up function
This back up battery adaptor circuit has DC supply function, from battery (+24V) to service unit and DC charge from service unit to
battery (+24V). Charge current is typ. 0.4A.
The AC input voltage is rectified and smoothed by D10-13 and C5. The obtained DC voltage is converted into a rectangular wave by
the switching transistor Q1, then isolated and transduced by T1. This converted rectangular wave is rectified and smoothed by
D101 and C101 to output DC27V. The DC27V is transmitted to the primary side by PC1 and then PWM- controlled to keep con-
stant. The switching frequency of Q1 is approximately 63KHz (55KHz~70KHz).
2) DC-DC Inverter Function
The DC27V as input is converted into a rectangular wave by the switching transistor Q201, then isolated and transduced by T2.
DC+15V, -15V and 3.3V are outputted by a rectification smoothing circuit composed of D401, D301, D701, C401, C301 and C702.
The +3.3V of the three outputs is PWM-controlled by IC201 to keep constant.The switching frequency of the Q2 is approx. 55 KHz.
3) Ringing signal output function
Ringing signal (20/25Hz, 75Vac from main board) is amplified in power by power amplifier circuits (including of IC501, R601~R608,
C601~C603).
Ringing signal amplified in power is transmitted to the ringing transformer through pin 4 of CN601.
4) Battery back up function
This back up battery adaptor circuit has DC supply function, from battery (+24V) to service unit and DC charge from service unit to
battery (+24V). Charge current is typ. 0.4A.
AC-DC Inverter Function
This function isolates and transduces the AC input voltage to DC input and output
of DC27V.
of DC27V.
DC-DC Converter Function
This function outputs DC+15V, -15V and 3.3V from the inputted DC27V.
Ringing Signal Output Function
Based on the 20/25Hz sine wave signal output from KX-TES824/KX-TEM824,
this function generates ringing and supplies to the system.
this function generates ringing and supplies to the system.
Battery Back Up Adaptor Function
This function connects battery and service unit without battery adaptor, only
needs a cable connected to the battery and service unit.
needs a cable connected to the battery and service unit.
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