Sharp Aquos LC-39LE440U, Руководство по обслуживанию

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UM102 is powered on to start issuing the gate drive signal , the high-voltage current source is then
disabled ,and the Vcc supply current is provided from the auxiliary winding of the transformer PIN3.
UM102 Pin3 is protection PIN.RM101 are sense circuit, UM102 detects the MOSFET current,
from the CS in. When CS pin over 0.73V, the UM102 will enter auto-recovery type protection,
Presenting a hiccup mode. The gate-out will not resume switching until OCP falls below 0.67V.
UM102 Pin1 is OVP protection PIN.
It receives ON/OFF signal from secondary scalar
controller. If the voltage of EN/DIS pin exceeds the enable threshold voltage 1.2V or EN/DIS pin is
floating, the system will be start-up. However, if the voltage of EN/DIS voltage is below the enable
threshold voltage 0.8V, the system will be shut down completely and consume almost zero power.
For low standby power application, it's important to make current in this path
as small as possible. The deglitch delay time of the disable function is about 20us. The internal
bias current of EN/DIS is 2uA. For low power consumption, it's a high impedance pin. Therefore,
proper layout is necessary for noise immunity. If capacitor is unavoidable, capacitor value
should be carefully calculated and not to influence system operation.
UM102 control 12V output , UM103, UM108, LM101 construct buck circuit to output 5V. UM104,
LM103 , QM105 construct buck circuit to output 12V.
ACD circuit is to make the backlight shutdown in time as son as AC input turn off .When
AC input turn on , the ACD signal will output a low voltage, then the main board receive this
low voltage to make backlight work normally. When AC input turn off , the ACD signal will
output a high voltage, then the main board receive this high voltage to make backlight
shutdown.