Service Manual
8
power MOSFETs to regulate the CCFL current.
2.1.2
Output Circuit and Protection Circuit operations:(fig.3)
1
2
+
C25
680u/25V
OP
C22
12pF/3KV
ISEN
DRV2
DRV2
VS2
ISEN
PID
CN5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
PIN1
PIN2
PIN3
PIN4
PIN5
PIN6
PIN7
PIN8
PIN9
PIN10
PIN11
PIN12
PIN13
PIN14
PIN15
VS2
DRV1
VS1
1
2
R21
133
+13V
C21
3pF/3KV
DRV1
OP
DIM/ON/OFF
T1
DIP EEL19 SPW-054
1
6
4
3
8
7
VS1
+5V
C20
3pF/3KV
R20
133
+13V
Fig.3
The transformer (T1) secondary winding leakage inductance and output
capacitance(C31) forms a lower pass filter,which converts the square-wave driving
signal into a sinusoidal output voltage signal for CCFL.
The over-voltage protection feature is implemented by using an extermal
capacitor devider(C20/C21) to sense the output voltage.The divide-down voltage
signal is sent to the IC Pin11(VSEN) ,thus regulating the output voltage.
If a CCFL is removed, fails or damaged during normal operation, CCFL current
is no longer sensed and the voltage on ISEN pin drops. Once the voltage at the ISEN
pin is less than the lamp” on” threshold, the shutdown timer is activated. The IC
maintains the output voltage for approximately 2-3seconds and once the timer expires,
the IC will shutdown. To restart the IC, either toggle the SST_CMP pin or recycle the
power on the VDDA pin.
2.2 Power PWM circuit operations
2.2.1) Block diagram:(fig.4)
EMI Filter
Rectifier and
filter
Isolation power
transformer
Rectifier and filter
Inverter circuit
Rectifier and filter
AUDIO
Содержание ST2010 - 20" LCD Monitor
Страница 1: ...Service Manual 0 Service Manual LCD Monitor ST2010 ...
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Страница 21: ...Service Manual 20 8 Key Parts Pin Assignments 8 1 U105 TSUMU58EDJ LF ...
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Страница 27: ...Service Manual 26 Chapter 4 Disassembly Assembly 1 Exploded Diagram ...
Страница 30: ...Service Manual 29 3 ST2010 Assembly Block ...
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Страница 60: ...Service Manual 59 Attachment 2 Schematic 1 Interface board schematic ...
Страница 68: ...Service Manual 67 power board schematic 1 ...
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Страница 72: ...Service Manual 71 Attachment 3 PCB Layout Power inverter board Top Layer ...
Страница 73: ...Service Manual 72 Bottom Layer ...
Страница 74: ...Service Manual 73 I F board Top Layer Bottom Layer ...
Страница 75: ...Service Manual 74 Keypad ...
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