Inverter Circuit And 1 Blink Sos - Panasonic TC-L42D2 Technical Manual

Inverter Circuit and 1 Blink SOS

The INV_ON/OFF command (high) of the MPU, IC8001 of the A board,
enters the P-Board to turn on the inverter circuit. The inverter circuit
produces AC voltages that power the backlight fluorescent lamps . The
output of the inverter, approximately 2Kvp-p is provided to the LCD panel
via the connectors P5, P6, P7 and P8.
To avoid catastrophic failures, when the inverter circuit is defective, the
INV_SOS command is output to IC8001 to trigger the shutdown of the TV.
The power LED blinks one time. The same operation takes place when
there is an impedance mismatch between the Panel and the inverter.
IC7800 is the controller. IC7801 is the oscillator that provides the switching
signals to the transistors Q7801 through Q7804.
The backlights are manipulated (dimmed) by the control signal INV_PWM
coming from the main board Via pin 12 of the connector P2.
Slide # 34