| 摘要 |
PROBLEM TO BE SOLVED: To obtain the video display device that can activate a spot killer circuit without being affected by a load change in a ternary winding of a flyback transformer. SOLUTION: A spot killer circuit 30 detects a trailing of a DC voltage V3 that is an output of a regulator circuit 3, and decreases a cathode voltage of a picture tube 12 so as to allow the cathode voltage to reach a cut-off voltage or below when the result of detection indicates a fall of the DC voltage. When a power switch of a television receiver is switched from on to off, a 1st DC power voltage Vl outputted from a main power supply 1 descends and the output of the regulator circuit 3 also decreases, and a transistor(TR) 31 of the spot killer circuit 30 is conductive. Thus, the spot killer circuit 30 decreases the cathode voltage of the picture tube 12 to the cut-off voltage or below and supplies a cathode current so as to prevent a fluorescent screen of the television receiver from being baked due to beam spots.
|
