| 摘要 |
PURPOSE:To realize the detection of excess current and the detection of excess voltage with a few circuit scale and to suppress X-ray radiation amount to specified amount and less. CONSTITUTION:When excess current exceeds VBE of a first detection transistor Qc, this is turned on, a third control transistor Qd is turned on by the voltage at that time and the supply of a horizontal drive signal is stopped. As the result, the oscillation of a flyback transformer 12 is stopped and X-ray is stopped to be radiated to specified amount and more by excess current. From excess current, a CRT and the flyback transformer 12 are protected. As a second detection transistor Qe is turned on at the time of excess voltage, the first detection transistor Qc is also turned on and a first control transistor Qa is compulsorily turned off. Thus, X-ray is not radiated to specified amount and more by excess voltage since the oscillation of the flyback transformer 12 is stopped. A second control transistor Qb can be protected also from excess voltage. |
