| 摘要 |
PROBLEM TO BE SOLVED: To allow the display device to operate so as to surely prevent destruction of a horizontal output transistor(TR) and to conduct screen display at a frequency after being changed over at the fastest in the case that a frequency of a horizontal synchronizing signal received by the display device is switched from a high frequency into a low frequency. SOLUTION: A CPU 101 is used to detect changeover of a frequency of a horizontal synchronizing signal to decrease a +B power supply voltage to prevent a horizontal output TR 106 from being destroyed and a feedback loop to always monitor a level of the reduced power supply voltage is provided. In this case, after confirming the voltage reaches a level in response to a frequency of the horizontal synchronizing signal after changeover, a control voltage for a horizontal oscillated frequency is switched into a control voltage for the horizontal oscillated frequency after the changeover. |
