Service Manual
10
Fig.3
The transformer (T1 to T12) secondary winding leakage inductance and
output capacitances that are in the inverter PCB board, forms a lower pass
filter, which converts the square-wave driving signal into a sinusoidal output
voltage signal for CCFL.
The voltage signal sensed through R14 comes to Pin13 of U1-ISEN (Lamp
Current Detection & Control). The CCFL current is detected through R14 and
reaches a regulated value. The CCFL current detected at resistor R13 and
R14 is converted to a voltage level and input to the ISEN pin. Once the voltage
at the ISEN pin reaches the lamp on threshold, the IC switches from the
striking mode to the normal operation mode and the PWM dimming control is
activated.
C21 is used to dump noise. Once the CCFLs are ignited and current is
sensed through resistor R14 ,capacitor C15 performs the loop compensation
function. The voltage at pin1, pin2, pin23 and pin24 controls the drive duty
cycle of the power MOSFETs to regulate the CCFL current.
Q5 off and Q6 on during normal operation. Once any one of ISs falls down,
gate of Q6 lost voltage, Q6 turns off and Q5 turns on, ISEN would be pulled
Содержание 2209WA - UltraSharp - 22" LCD Monitor
Страница 1: ...Service Manual 0 Service Manual LCD Monitor 2209WA ...
Страница 25: ...Service Manual 24 8 Key Parts Pin Assignments 8 1 U105 TSUMU58EHJ LF ...
Страница 26: ...Service Manual 25 ...
Страница 27: ...Service Manual 26 ...
Страница 31: ...Service Manual 30 ...
Страница 32: ...Service Manual 31 Chapter 4 Disassembly Assembly 1 Exploded Diagram ...
Страница 36: ...Service Manual 35 Note 1 The arrows point out the direction of assembly ...
Страница 44: ...Service Manual 43 ...
Страница 80: ...Service Manual 79 ...
Страница 81: ...Service Manual 80 Attachment 3 PCB Layout power inverter bd inverter board Top Layer Bottom Layer ...
Страница 82: ...Service Manual 81 Main board Top Layer ...
Страница 83: ...Service Manual 82 Bottom Layer ...
Страница 84: ...Service Manual 83 Keypad USB convert board ...
Страница 85: ...Service Manual 84 ...