US 4,362,974 AGranted

Commutated switched regulator with line isolation for transistor deflection

AssigneeRCA Corporation

InventorWolfgang F. W. Dietz

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Abstract

A transistor horizontal deflection circuit is energized from a source of unregulated direct voltage derived from the power mains but is conductively isolated therefrom. A switching voltage regulator couples the direct voltage source to the horizontal deflection circuit. The regulator includes a controllable switch serially coupled with the primary winding of a transformer and the source. The switch is controlled to maintain a constant voltage or energy level in the horizontal deflection circuit. A secondary winding conductively isolated from the primary is coupled across the deflection winding for forming a path for bidirectional current flow. The horizontal output transistor is coupled in parallel with the deflection winding for producing retrace pulses which are coupled to the primary winding for reducing the current in the controllable switch to zero during the retrace interval.

Claims16

Dependent claims

A regulated television deflection apparatus adapted to be energized by and isolated from a source of unregulated direct voltage, comprising:

regulator switch means including a controlled, main, current path and a control electrode;
a transformer including a primary winding serially coupled with said main current path and with said source for coupling energy from said source to said primary winding when said main current path is conductive in a first direction, said transformer further including a secondary winding conductively isolated from said primary winding;
a deflection winding coupled across said secondary winding for forming a path for the bidirectional flow of current therebetween;
a trace switch coupled in parallel with said deflection winding and operated at the horizontal rate for promoting the flow of deflection current in said deflection winding during trace and retrace intervals of each deflection cycle;
and
control means coupled to said control electrode and to an energy sensing point on the apparatus for making said main current path conductive at a controllable instant during said trace interval that varies as said unregulated direct voltage varies for maintaining the voltage at said point substantially constant, said main current path remaining conductive after said controllable instant until the occurrence of said retrace interval when the voltage across said deflection winding is applied to said secondary winding for inducing a current in said primary winding that reduces the current in said main current path to zero during said retrace interval and thereafter said main current path is substantially nonconductive in said first direction until the reoccurrence of said controllable instant within the subsequent trace interval.

3 more elements

A regulated television deflection apparatus adapted to be energized by and isolated from a source of unregulated direct voltage, comprising:

regulator switch means comprising a silicon controlled rectifier having a controlled, main, current path comprising the anode-to-cathode path thereof and a control electrode;
a diode paralleling said anode-to-cathode path;
a transformer including a primary winding serially coupled with said main current path and with said source for coupling energy from said source to said primary winding when said regulator switch means is on, said transformer further including a secondary winding conductively isolated from said primary winding;
a deflection winding coupled across said secondary winding for forming a path for the bidirectional flow of current therebetween;
a trace switch coupled in parallel with said deflection winding and operated at the horizontal rate for promoting the flow of deflection current in said deflection winding during trace and retrace intervals of each deflection cycle, wherein the voltage across said deflection winding during said retrace interval is coupled to said primary winding for reducing the current in said main current path to zero during said retrace interval thereby turning said regulator switch means off, said diode conducting current from said primary winding during said retrace interval when said silicon controlled rectifier is turned off;
and
control means coupled to said control electrode and to an energy sensing point on the apparatus for varying the time during said trace interval at which said regulator switch means is turned on as said unregulated direct voltage varies for maintaining the voltage at said point substantially constant.

4 more elements

A regulated deflection circuit with a start-up arrangement, comprising:

a deflection winding;
a trace switch coupled to said deflection winding and responsive to a deflection rate switching signal for generating deflection current in said deflection winding within a deflection cycle, a retrace pulse voltage being developed across said deflection winding during a retrace interval of said deflection cycle;
a storage capacitor;
a transformer having first and second windings conductively isolated from each other, said second winding series coupled with said storage capacitor across said trace switch;
a source of input voltage;
a regulator switch for applying said input voltage to said transformer first winding to store energy in said transformer;
a control circuit coupled to said regulator switch and responsive to a deflection circuit energy level for turning on said regulator switch at a controlled instant within a trace interval of said deflection cycle, said instant varying with variations in said deflection circuit energy level to control the amount of stored energy in said transformer, said stored energy being transferred to said deflection circuit during said retrace interval, said retrace pulse voltage being applied to said transformer second winding to produce a decreasing magnitude current in said transformer first winding that turns off said regulator switch during said retrace interval;
a source of voltage conductively isolated from said transformer first winding and available during an initial turn-on interval;
and
start-up means for charging said storage capacitor from said isolated, available voltage source to develop a deflection circuit operating voltage during said initial turn-on interval, the subsequent operation of said trace switch increasing the direct voltage across said storage capacitor.

7 more elements

Dependencies are inferred from the claim text.