Dell E1909W - 8.3 U850 (LD7552 B, PWM Power Controller); 8.4 U1 (INL833, CCFL Inverter controller IC)

Service Manual
19
8.3 U850 (LD7552B, PWM Power Controller)
Pin
Symbol
I/O
Description
1
GND
Ground
2
COMP
I
Voltage feedback pin,by connecting a photo-coupler
to close the control loop and achieve the regulation
3
VCC
I
Supply voltage pin
4
RT
I
This pin is to program the switching frequency. By
connecting a resistor to ground to set the switching
frequency.
5
NC
Unconnected pin
6
CS
I
Current sense pin,connect to sense the MOSFET
current.
7
VCC
I
Supply voltage pin
8
Out
O
Gate drive output to drive the external MOSFET
8.4 U1 (INL833, CCFL Inverter controller IC)
Pin
Symbol
I/O
Description
1
VSEN
I
Voltage Sense Feedback
2
SSTCMP
I
Capacitor for Soft-Start and loop Compensation
3
CT
I
Timing Resistor and Capacitor for Operation and
Striking Frequency
4
RT
I
Timing Resistor for Striking Frequency
5
GNDA
Signal Ground
6
PDR2
O
High Side Driver Output2
7
GNDP
Power Ground
8
NDR2
O
Low Side Driver Output2
9
NDR1
O
Low Side Driver Output1
10
PDR1
O
High Side Driver Output1
11
VDDA
I
Input Power Pin
12
TIMER
I
Timing Capacitor for Delay Timer
13
PWM
I
Ecternal PWM Dimming Input
14
ISEN
I
Current Sense Feedback
15
OVPT
I
Over-Voltage Protection Threshold Voltage
16
ENA
I
IC Enable/Disable