Rush Current Control Circuit - Epson TM-U675 Service Manual

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Rush Current Control Circuit

The rush current control circuit controls rush current when the power source is turned on. This
printer has large-capacity condensers to facilitate stable operation of mechanism drivers and
circuits. Therefore, an excess of rush current is generated when the power is turned on. This
circuit controls the rush current.
An external power supply is connected to the CN18. A switch is connected to CN29. When the
switch is turned ON, the voltage at Q61 Gate-Source is "0" because Q61 is OFF and C605 is not
energized. For that reason, there is no current flowing. After that, the voltage to Gate-Source
gradually rises according to the time constant determined by C605 and R245 to gently raise the
output voltage. This restricts the sudden flow of current to the capacitors.
CN29
1
2
F1
CN18
1
2
3
SH
Rev.D
L3
D16 C40
Figure D-64 Rush Current Control Circuit
TM-U675/U675P (with autocutter) Service Manual
C605 R244
C41
Product Overview Appendix D-67
24VB
Q61
C42 C43
R245
C44