Signal (Refer To The Timing Chart) - Dell 2005FPW - UltraSharp - 20.1" LCD Monitor Service Manual

50 ~ 60Hz
EMI
COMPONENTS
LINE
100 ~ 240V
1. EMI components.
This part contains of EMI components to comply with global marketing EMI standards like FCC,VCCI CISPR,
the circuit included a line-filter, across line capacitor and of course the primary protection fuse.
2. Input rectifier and filter.
This part function is for transfer the input AC voltage to a DC voltage through a bridge rectifier and a bulk capacitor.
3. Energy Transfer.
This part function is for transfer the primary energy to secondary through a power transformer.
4. Output rectifier and filter.
This part function is to make a pulse width modulation control and to provide the driver signal to power switch,to
adjust the duty cycle during different AC input and output loading condition to achieve the dc output stabilized, and
also the over power protection is also monitor by this part.
5. Photo-Coupler isolation.
This part function is to feed back the dc output changing status through a photo transistor to primary controller to
achieve the stabilized dc output voltage.
6. Signal collection.
This part function is to collect the any change from the dc output and feed back to the primary through photo
transistor
7. Inverter
The inverter converts from DC12V to AC 840Vrms and operate back-light lamp of module.
INPUT RECTIFIER
AND FILTER
PWM CONTROL
CIRCUIT
PRIMARY
12V
Operation description_Power
HVDC
SWITCHING
TRANSFORMER
PHOTO -COUPLER
ISOLATION
INVERTER CIRCUIT
- 11 -
100KHz
OUTPUT RECTIFIER
AND FILTER
SIGNAL
COLLENT-
ION
SECONDARY
High Voltage
12V
5V
GND