| 摘要 |
PROBLEM TO BE SOLVED: To securely interrupt high voltage even if the beam current of CRT increases to more than a prescribed value with circuit constitution which is simpler than a former one. SOLUTION: At the time of driving/controlling a high voltage output circuit applying high voltage to the anode of CRT by a high voltage control circuit 4, the high voltage control circuit 4 is constituted to stabilize high voltage output based on high voltage feedback voltage Vhfb obtained by feeding back the high voltage output of the high voltage output circuit 1. A voltage value detection circuit 2 detecting the high voltage output of the high voltage output circuit 1 is provided. When the detection voltage of the high voltage value detection circuit 2 increases with the increase of the beam current of CRT and it becomes more than a reference value, the high voltage output of the high voltage output circuit 1 is stopped. |
