Service Manual
10
When the sense voltage across the sense resistor R859, reaches the threshold voltage around 0.85v,
the output GATE drive will be turned off. Every time when the output of power supply is shorted or over
loaded, the FB voltage will increase, the build-in PWM output will then be turned off. Both of two will
prevent the power supply from being overheated under over loading condition. The PWM duty cycle is
determined by this current sense signal and VFB, the feedback voltage, when the voltage on sense pin
reaches V-
(PWMcopm)
=(V
comp
-
2V
F
)/3, A switch cycle will be terminated immediately, Vcomp is internally
clamped to a variable voltage around 0. 85 V for output power limit
When Q850 are turned off, the main current flow will be consumed through D85
1
, C8
75
,
R853/R854/R855
and D853
, This will prevent Q850 from being damaged under large current impulse and
voltage spike.
2.2.4)DC_
27
V and 5V Output Circuit and Feedback circuit:(fig.7)
fig.7
D854/D855 is used to rectify the inducted current.
C
86
2
is used to store energy when current is
reversed. The parts including C8
63
are used to smooth the current waves that are from D854/D855, then
27V voltage is supplied;
D8
60
is used to rectify the inducted current. R86
1
and C8
73
are used to store energy when current is
reversed. The parts including C8
66
, C8
67
, C868, and L85
4
are used to smooth the current waves that are
from D8
60
, then
5
Vvoltage is supplied;
27
V and 5V supply voltage feed back to PWM controller U850 via R871, R872, R868 and
I850,I851.R86
0
,C8
59
and C8
71
used to control respond time.
Содержание E2209Wf
Страница 1: ...Service Manual 0 Service Manual LCD Monitor E2209Wf ...
Страница 7: ...Service Manual 6 Fig 12 ...
Страница 16: ...Service Manual 15 8 Key Parts Pin Assignments U105 TSUMU58EHJ LF 2 ...
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Страница 21: ...Service Manual 20 Chapter 4 Disassembly Assembly 1 Exploded Diagram ...
Страница 22: ...Service Manual 21 2 E2209WFPf Disassembly Block Note 1 The arrows point out the direction of disassembly ...
Страница 23: ...Service Manual 22 3 Assembly Block Note 1 The arrows point out the direction of assembly ...
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Страница 46: ...Service Manual 45 2 power board schematic ...
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Страница 50: ...Service Manual 49 Attachment 3 PCB Layout power inverter bd power inverter board Top Layer ...
Страница 51: ...Service Manual 50 Bottom Layer ...