High efficiency deflection circuit
First Claim
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1. A deflection circuit comprising:
- first and second serially coupled transistors forming a push-pull amplifier stage coupled to a first source of relatively low direct operating voltage, a junction of said first and second transistors forming an output terminal;
a deflection winding and a feedback resistor serially coupled to said output terminal and a point of reference potential;
a driver stage coupled to said amplifier stage and said feedback resistor and responsive to a source of input signals for defining trace and retrace intervals during each deflection cycle;
first switching means coupled in a main current conduction path of said first transistor and said deflection winding; and
second switching means coupled to said output terminal and a second source of relatively high direct operating voltage and responsive to signals obtained from said driver stage for coupling said deflection winding to said second source only during said retrace interval;
said first switching means serving to disconnect the main current conducting path of said first transistor when retrace voltage developed across said deflection winding exceeds said first source voltage, and said feedback resistor sampling current in said deflection winding for determining the end of said retrace interval and the start of the next succeeding trace interval.
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Abstract
A push-pull common emitter deflection output stage energized by a relatively low direct voltage includes zener diode drive coupling to its input circuit for reducing crossover distortion. A diode in series with a deflection winding disconnects the output stage from the winding during a portion of the retrace interval to allow the retrace pulse voltage to rise to a relatively high direct voltage supplied through a switched transistor only during the retrace interval to reduce power dissipation in the output stage. Current feedback from the deflection winding to a driver stage during trace and retrace intervals accurately determines the retrace duration.
35 Citations
5 Claims
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1. A deflection circuit comprising:
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first and second serially coupled transistors forming a push-pull amplifier stage coupled to a first source of relatively low direct operating voltage, a junction of said first and second transistors forming an output terminal; a deflection winding and a feedback resistor serially coupled to said output terminal and a point of reference potential; a driver stage coupled to said amplifier stage and said feedback resistor and responsive to a source of input signals for defining trace and retrace intervals during each deflection cycle; first switching means coupled in a main current conduction path of said first transistor and said deflection winding; and second switching means coupled to said output terminal and a second source of relatively high direct operating voltage and responsive to signals obtained from said driver stage for coupling said deflection winding to said second source only during said retrace interval; said first switching means serving to disconnect the main current conducting path of said first transistor when retrace voltage developed across said deflection winding exceeds said first source voltage, and said feedback resistor sampling current in said deflection winding for determining the end of said retrace interval and the start of the next succeeding trace interval. - View Dependent Claims (2, 3, 4, 5)
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Specification