| 摘要 |
A horizontal deflection circuit of a television receiver includes a horizontal deflection winding, a retrace capacitor and a trace switch comprising a damper diode and a horizontal output transistor. A horizontal oscillator provides a synchronized deflection rate square-wave voltage to a base-drive generator circuit for the horizontal output transistor. The base-drive generator circuit develops a forward biasing portion of the horizontal output transistor base-drive signal to maintain the transistor in saturated conduction during the latter portion of trace. The generator also develops a reverse biasing portion to initiate horizontal retrace after the output transistor collector current is cut off. A lapse of a turn-off delay time occurs from the initiation of the reverse biasing portion of the base-drive signal to the collector current cutoff instant. Energy is transferred from an unregulated input supply to television receiver load circuits through an inductance such as a flyback transformer. A controllable switch is coupled to the inductance. The switch is turned on within each deflection cycle to enable energy from the unregulated input supply to be stored in the inductance during the latter portion of the trace interval. A retrace pulse voltage applied to the inductance initiates the energy transfer interval. To regulate the energy transfer, the turn-off delay time of the horizontal output transistor is controlled, thereby controlling the initiation of the retrace and energy transfer interval. |
