| 摘要 |
PROBLEM TO BE SOLVED: To provide a protective circuit for a horizontal output transistor which is capable of protecting the horizontal output transistor against damage caused by the single lack of a horizontal oscillation pulse of "H" level, and in addition by the continuous lack of horizontal oscillation pulses and the lack of horizontal oscillation pulses of "H" level, after returnings due to making the transistor an IC construction. SOLUTION: The horizontal output transistor protective circuit is equipped with a current limiting resistor 11 which limits a current that is inputted into the primary side of a horizontal drive transformer 5 connected to the horizontal output transistor 6, a smoothing capacitor 12 which smoothes a voltage between the current limiting resistor 11 and the horizontal drive transformer 5, a horizontal oscillation pulse-lacking detection circuit 8 which detects that a horizontal oscillation pulse is lacking and outputs horizontal oscillation pulse-lacking detection signals, and a timer circuit 10 which outputs signals of forcibly turning on a horizontal drive transistor 3 that turns on/off the primary side of the horizontal drive transformer 5 for a prescribed time which is previously set when the horizontal oscillation pulse-lacking detection signals are inputted. COPYRIGHT: (C)2005,JPO&NCIPI |
