High-voltage transformer for a televison receiver including separated partial windings tuned to different harmonics

Abstract

A high-voltage transformer for a television receiver is known to be tuned to a specific harmonic of the frequency of the flyback oscillation in order to reduce the internal resistance of the high-voltage source. In certain cases such as, for example, a channel change, a particularly high beam current of the order of magnitude of 3 to 5 mA briefly occurs. As a result of such a current surge, overshoots are produced at the transformer which may increase the flyback voltage at the switching transistor by approximately 150 V and thus endanger the transistor. The object is to design the transformer in such a way that overshoots of this type are reduced. According to the invention, the number of partial windings (W2-W5) is greater than the number of diodes (3-5), and separate partial windings (W2-W5) are tuned to different harmonics. This tuning causes the quality factor to be reduced and the attenuation and the bandwidth to be increased in the system. As a result, the flyback pulse at the high-voltage winding becomes larger and wider and the internal resistance of the high-voltage source is reduced. In addition, interfering overshoots of this pulse, which bring about an increase in the amplitude of the flyback pulse at the primary winding, are significantly reduced. In particular, high-voltage transformer for a television receiver having an increased high voltage.

Dependencies are inferred from the claim text.