| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability by opening FET switches sequentially when a voltage in response to frequency reaches a prescribed value or over so as to decrease a base current, thereby minimizing a loss in a horizontal output transistor(TR). SOLUTION: A horizontal drive correction circuit 1 converts a repetitive pulse input into a DC voltage, in response to a frequency and a base resistor of a horizontal deflection output TR 7 is open depending on the DC voltage. That is, the horizontal synchronizing signal is converted into a voltage, in response to a frequency by a frequency - voltage converter 29. When the voltage reaches a prescribed voltage or over, diodes 25, 26 clamp the voltage to activate inverting amplifiers 19, 16 and to open switching FETs 11, 14. Then a clamp voltage is selected in a range where a switching heat loss of the output TR 7 is not excessive, so as to prevent destruction. A horizontal deflection output circuit 2 uses the TR 7 to discharge charges stored in an S-shaped capacitor 4 to a deflection yoke 3 and to invert them through the resonance between a yoke 2 and a capacitor 5, thereby supplying a current to the yoke 3. |
