High-voltage power supply for a picture tube
AssigneeBlaupunkt-Werke GmbH
InventorKarl-Hans Schmadel
Life of this patent
Estimating the term…
Abstract
The primary winding of a high-voltage transformer is periodically connected to an operating voltage source at the television line scanning frequency. The secondary winding is subdivided into several component windings which are connected to each other through diodes. A further diode provides the output for the high voltage. A somewhat similar circuit with interposed diodes can provide a center tap and full-wave rectification. A control voltage derived by voltage division from the high voltage is supplied to regulating means for holding the high voltage constant by controlling the width of the driving pulses for the semiconductor switch or by directly controlling the operating voltage connected to the transformer through the semiconductor switch.
Claims12
Circuit for producing a high voltage for operation of a picture tube, comprising:
- a transformer (16) having a primary winding and a primary winding circuit including a source of operating voltage (19) and a semiconductor switch (17) connected in series between said primary winding and said source of operating voltage for periodic connection of said transformer primary winding to said operating voltage source, said transformer also having a secondary winding subdivided into several component windings (1, 2, 3;
- 31, 32, 33, 34) connected together at least in some cases through diodes (4, 5;
- 35, 37);
- at least one additional diode (6;
- 36, 38) being provided between a component winding (1;
- 31, 34) and an output terminal for providing a high voltage,
- a voltage divider (9, 10, 11, 12, 13) connected between said output terminal for high voltage and a ground connection and having a first adjustable output for suppluing focussin voltage, a second adjustable output for providing screen grid voltage and in addition a third fixed output (14) for supplying a control voltage, which third output is electrically nearer said ground connection than are said first and second outputs of said voltage divider, and
- means for regulating said high voltage towards constancy in response to said control voltage.
Circuit for producing a high voltage for operation of a picture tube, comprising:
- a transformer (16) having a primary winding and a primary winding circuit including a source of operating voltage (19), a semiconductor switch (17) connected in series between said primary winding and said source of operating voltage for periodic connection of said transformer primary winding to said operating voltage source, and at least one capacitor (21), said transformer also having a secondary winding subdivided into several component windings (31, 32, 33, 34) connected together at least in some cases through diodes,
- at least one additional diode (36, 38) being provided between a component winding (31, 34) and an output terminal for providing a high voltage,
- said transformer, said semiconductor switch, said diodes and said at least one capacitor consituting a voltage converter wherein, during non-conducting phases of said semiconductor switch (17), an approximately sinusoidal oscillation takes place;
- a voltage divider (9, 10, 11, 12, 13) connected to said output terminal for high voltage and having an output (14) for supplying a control voltage, and
- means for regulating said high voltage towards constancy in response to said control voltage.
Dependencies are inferred from the claim text.