High voltage disabling circuit for a television receiver
AssigneeRCA Corporation
InventorDonald H. Willis
Life of this patent
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Abstract
A deflection generator develops scanning current in a horizontal deflection winding. A high voltage winding of a flyback transformer generates a high voltage for the picture tube ultor terminal. A high voltage safety circuit includes a flyback transformer secondary winding for applying a peak detected retrace pulse voltage to a disabling latch circuit. If the high voltage exceeds predetermined values, the latch is energized and disables normal operation of the deflection generator. Components of the sustaining current that maintains the latch in a regeneratively conducting state are derived from two voltage sources, with the current component derived from one of the two voltage sources by itself insufficient to maintain the latch in the regeneratively conducting state.
Claims6
A deflection and high voltage system with a disabling circuit, comprising:
- a deflection winding;
- a deflection generator coupled to said deflection winding for generating scanning current in said deflection winding;
- a transformer coupled to said deflection winding;
- high voltage generating means coupled to said transformer for generating a high voltage;
- detection means responsive to said high voltage for generating a first signal representative of high voltage;
- a disabling latch coupled to said detection means and to said deflection generator for generating a disabling signal for disabling normal deflection generator operation upon energization of said latch by said detection means when said first signal exceeds predetermined values;
- and
- means coupled to said disabling latch for providing a sustaining current to said latch for maintaining said latch in a regeneratively conducting state upon latch energization;
- wherein said sustaining current providing means includes a first source of voltage coupled to said disabling latch for providing a first component of said sustaining current to said latch, and a second source of voltage coupled to said disabling latch for providing a second component of said sustaining current to said latch, at least one of said first and second sustaining current components being by itself of insufficient magnitude to maintain said disabling latch in a regeneratively conducting state.
Dependencies are inferred from the claim text.