Over
Over
-
-
Current Protection Circuit 2
Current Protection Circuit 2
34
Sound_VCC Protection
During normal operation, the 24 volt output of the P board biases the transistor Q7208 into conduction,
causing its collector to become low. The low at the collector of Q7208 causes the transistor Q7214 to turn off. When
the PANEL_MAIN_ON command (high) is issued Q7212 turns on. Consequently Q7225 turns off, and IC7215 goes
into conduction to provide the SOUND_15V output.
When the 24 drops below the reverse breakdown voltage of D7206, Q7208 turns off, Q7214 turns on to
ground the PANEL_MAIN_ON voltage. Q7212 turns off and Q7225 turns on. IC7215 ceases to operate and the
Sound_VCC is no longer output.
During normal operation, the anode of D7469 receives 5V and the junction of D7469, D7470, R7486,
and R7492 receives 12V. Due to this condition, the transistor Q7210 remains off. If the SOUND_15V line becomes
shorted, diode D7469 goes into conduction to turn Q7210 on. Consequently Q7210 outputs a high to shut down the
unit.
Panel_VCC Protection
During normal operation, the 24 volt output of the P board biases the transistor Q7208 into conduction,
causing its collector to become low. The low at the collector of Q7208 causes the transistor Q7508 to turn off. When
the PANEL_VCC_ON command (high) is issued, Q7702 turns on. Consequently Q7701 turns off, and IC7212 goes
into conduction to provide the PANEL_12V output.
When the 24 drops below the reverse breakdown voltage of D7206, Q7208 turns off, Q7508 turns on to
ground the PANEL_VCC_ON voltage. Q7702 turns off, and Q7701 turns on. IC7212 ceases to operate and the
Panel_VCC is no longer output.
During normal operation, the anode of D7472 receives 5V and the junction of D7472, D7473, R7493,
and R7488 receives 12V. Due to this condition, the transistor Q7210 remains off. If the Panel_12V line becomes
shorted, diode D7472 goes into conduction to turn Q7210 on. Consequently Q7210 outputs a high to shut down the
unit.
When the unit is turned on, the TV_Main_On command (high) of IC1100 biases the transistor Q7212 into
operation, causing its collector to become “low”. The low at the collector of Q7212 causes the transistors Q7225 to
turn off. As a result, IC7215 goes into operation to provide the Sound_15V output.
To Next Page
Loading...
