| 摘要 |
PURPOSE: To obtain an excellent image by preventing the overshoot. CONSTITUTION: A digital signal Xda so controlled as to gradually rise by a one-chip microcomputer 15 is sent to a comparator 57 as a reference voltage value Vrefpr via a D/A converter. The comparator 57 compares the output value of a smoothing circuit 56 with the sent value Vrefpr, and sends an output responsive to the difference of the both to a transformer driver 54. The driver 54 controls the voltage to be inputted to the transformer in response to the output of the comparator 57. That is, since the signal Vrefpr is gradually raised in response to the signal Xda, a DC high voltage supplied to a primary charger is gradually raised up to a target voltage value Vpr, thereby preventing the overshoot immediately after driving the transformer. |
