Panasonic KX-NCP1000GR, Service Manual

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KX-NCP500GR
4.6.2. Main Converter
Provides a description of the main converter that insulates primary DC voltage and converts it to secondary (32V output, 41V
output and 41V SW output).
1. Main converter section (primary side)
Consisting of the following parts, the primary side main converter is an insulated, separately-excited flyback converter.
Q1: Main switch FET
T1: Insulated transformer
IC1: Control IC for Q1 control
PC1: Secondary control transmission element
Other peripheral circuitry
Secondary output status is transmitted from PC1 to the primary side; on/off control is executed by IC1 to control secondary
voltage.
2. Main converter section (secondary side)
The T1 insulated transformer output consists of the following three outputs, and is the source of power for the output voltage
section described in Part 3.
32V output section:
Primary control output consisting of D201 and C201 - C204 rectifier smoothing circuits.
Serves as the source of power for 15V and 15 VPT output described in Part 3.
Controls output voltage by IC201 and R203 - R205 and transmits control status to primary side by PC1.
41V output section:
Output consisting of D101 and C101 rectifier smoothing circuits.
Serves as the source of power for 41V output described in Part 3.
41V switch output:
Consisting of D601 and C601 rectifier smoothing circuits, 41V switch output serves as source of power for FET Q151 for 41V
output control described in Part 3.
3. Latch Operation Section
Latch circuit for main converter stop due to abnormal state such as excessive output voltage.
Transmits abnormal state detected on secondary side (described in Part 5) to IC1 by PC50 primarily using the IC1 latch func-
tion and stops the main converter by latching.
Latching is canceled 30 seconds after the source of the abnormal state is removed and AC input is off, and is reset to ordinary
operation when AC power is turned back on.