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2.2.5.1 +5
V Current Limiting and Voltage Regulator Circuits
The + 5 V current limiting and voltage regulation is performed by controlling the ON/OFF time of
switching transistor
1.
Current Limiting
Figure 2-25 shows the + 5 V current limiting circuit.
The +5 V current limiting is controlled by
10
I I
R3
T1
a comparator (IC 1
3’
3
L3
m
-
(
+ 5
T
I
1
I
1
L -- -- -
P c l
Figure 2-25. +5 V Current Limiting Circuit
Reference voltage
which is obtained by dividing the + 5 V output by
and
is supplied to
the plus side (pin 3) of
1. Voltage
which is proportional to the current flowing through current
detection resistor R20, is supplied to the minus side (pin 2) of
1.
As the load at
increases,
When
<
the output
1 ) of
1
changed from
+ 12 V (HIGH) to O V (LOW)
by Zener diode ZD 1 and R 14. ZD 1 keeps the voltage at the cathode side
of the photo transistor in photo coupler PC 1 constant. At this time, the photo diode and photo transistor
of PC 1 turns on, transistor Q2 turns on, and Q 1 turns off.
The collector current for the transistor of PC 1 is supplied by D3, C 10, and the primary side of coil
. . .
2-32
Содержание LQ-2550
Страница 1: ...L Q 2 5 5 0 TECHNICAL MANUAL EPSON ...
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Страница 241: ...REV A 7 i_ Figure 6 4 LQ 2550 Lubrication and Adhesive Application Points Diagram 3 6 4 ...
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Страница 297: ...REV A 1 L I Irl N I i t 1 I I x Figure A 50 ROPSE Board Circuit Diagram A 52 ...
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