Panasonic KX-TDA0103XJ Service Manual page 46

KX-TDA0103XJ / KX-TDA0104XJ / KX-TDA0108XJ / KX-TDA0103X / KX-TDA0104X / KX-TDA0108X
8.3.1.1. AC Input ~ PFC Output
This section explains about the operations of AC filter circuit, Rectifier circuit and PFC circuit.
1) Filter Circuit, Rectifier Circuit 1
The filter part eliminates the noise from power supply unit not to leak it out, and also the circuit prevents an incoming noise.
Varistor Z1 deals with the excessive surge voltage from thunder, etc.
Rectifier circuit 1 rectifies input AC voltage at D1, which is input to PFC circuit.Varistors Z4 and Z5 deal with the excessive surge
voltage from thunder, etc.
Refer to Fig.1 (A), (B), (C)
2) PFC Switching Circuit
Rectified input voltage at D1 is boosted by the switching operation of transformer T1 (Main winding), FETs Q6 and Q7, diode
D19, and smoothed by electrolytic capacitors C18 and C19.
The voltage between both terminals of C18 and C19 becomes PFC output voltage (DC420V TYP.).
Refer to Fig.1 (D)
46