Q7C3 LCD Monitor Service Guide
Circuit Operation Theory
6
#5 PWM Controller
The PWM controller NCP1200A implements a standard current mode architecture. With an internal
structure operating at a fixed 40KHz. Where the switch time is dictated by the peak current set-point.
When the current set-point falls below a given value. The output power demand diminishes, the IC
automatically enters the so-called skip cycle mode and provides excellent efficiency.
Fig. 6
#6 Feedback circuit
PC123 is a photo-coupler and TL431 is a shunt regulation. They are used to detect the output
voltage change and be the primary and secondary isolation. When output voltage changes, the
feedback voltage will be compared and duty cycle will be decided to control the correct output
voltage. (See Fig.7)
Fig. 7
Содержание Q7C3
Страница 19: ...Q7C3 LCD Monitor Service Guide Engineering Specification 19 Fig 1 Physical Dimension Front View and Side view...
Страница 27: ...Q7C3 LCD Monitor Service Guide Alignment Procedure 7 E Tapes on backlight wire F Spring at the top of BKT...
Страница 29: ...Q7C3 LCD Monitor Service Guide Alignment Procedure 9 I Backlight wire J Two screws on panel left side...
Страница 33: ...Q7C3 LCD Monitor Service Guide Alignment Procedure 13 Q Paste aluminum tape on the backlight wire hole...
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