Thomson Consumer Electronics Inc.

Kenneth J Helfrich

Joseph C Stephens

David Ross Jackson

Paul D Henry

Kevin E Nortrup

Brian Lee

Kevin E McClain

A method and apparatus for apportioning standby power implements a first transition mode between standby and run modes of operation in which a control circuit is energized by a standby power supply in a fully active state and generates an on/off command signal responsive to detection of an input signal and a second transition mode between the standby and run modes of operation in which the control circuit is energized by the standby power supply in a partially active state and generates the on/off command signal and a drive signal generator is fully energized by the standby supply. An intermediate transition mode may also be implemented between the first and second transition modes, in which the control circuit and the generator are both energized in a fully active state for a brief interval by the standby power supply and an auxiliary energy source.

Apportioning minimal standby power

An automatic degaussing circuit provides a video display apparatus with a degaussing capability over a wide range of ac mains sources. An ac mains source is coupled to a degaussing coil by a series interconnection of first and second temperature-sensitive resistances. The temperature-sensitive resistances have oppositely-tending temperature coefficients, so that a total dc impedance of the automatic degaussing circuit initially decreases after power is applied to the circuit.

Degaussing circuit for wide-range ac

A horizontal deflection circuit couples flyback pulses from a first transformer winding to a second transformer winding. The second winding is coupled to a source of unregulated DC voltage. A switch has input, output and control terminals. The output terminal is coupled to the first winding. The switch operates with a variable duty cycle for generating a regulated DC voltage at the output terminal. An inductor and a diode are coupled to the second winding. The inductor is also coupled to the input terminal. A pulse width modulator varies the duty cycle of the switch responsive to feedback and timing signals. Drive voltage for the control terminal is supplied by a first capacitor charged during retrace intervals and a second capacitor charged at the end of the retrace intervals by the first capacitor. The second capacitor is coupled to the control terminal and the drive voltage is discharged by the pulse width modulator.

Switching power supply regulator with an inductive pulse circuit

A free running frequency alignment method in a video display having a sync generator comprising a first oscillator having a first frequency and a second oscillator having a second frequency. The first oscillator is phase modulated by the second oscillator which has a free running frequency different from a standard frequency. The free running frequency of the first oscillator is to be controllably aligned to the standard frequency by a method comprising the steps of applying a frequency determining initial control value to the first oscillator and measuring an average free running frequency responsive to the initial control value. An absolute difference frequency is calculated between the average frequency and the standard frequency. The absolute difference frequency is tested for a frequency value less than a predetermined value which signifies an aligned condition. If the difference frequency is less than the predetermined value the alignment is complete. If the difference frequency is greater than the predetermined value the alignment is continued and a new control value is generated responsive to the difference. The new control value is applied to the first oscillator and the steps of average frequency measurement, absolute difference frequency calculation and difference frequency value testing are repeated until alignment is achieved. Upon failure of the difference frequency test, a counter is incremented and the count examined to determine if a predetermined number of alignment attempts have been exceeded. Upon exceeding the predetermined number the alignment is determined to have failed and the alignment is ended.

Oscillator free run frequency setting by data bus control

A deflection apparatus comprises a deflection amplifier coupled to a deflection waveform modulation circuit such as a diode modulator. A source for generating a modulation signal. The modulation signal comprises a symmetrical periodic AC component having equal first and second portions of a trace period. A feedback amplifier alters the amplitude of a first portion of the trace period relative to a second portion of the trace period to render the AC component asymmetrical. The asymmetrical AC component is coupled to the deflection waveform modulation circuit for deflection waveform modulation.

Deflection waveform correction circuit

A video display has microcomputer control via a data bus and comprises a first sync generator coupled to the data bus for control by data thereon. A second sync generator is without controllable coupling to the data bus. A deflection amplifier is coupled to a deflection coil for generating a deflection current therein. A circuit for controlling the second sync generator is coupled to the first sync generator and is responsive to a digitally controlled signal therefrom. The second generator output signal is coupled to the deflection amplifier for deflection generation responsive to the digitally controlled signal.

video display device employing two SYNC generators

A scanning waveform generator for operation at a first or a second scanning frequency comprises a source of a parabolic shaped signal having a frequency selectable between the first or second scanning frequency. A means for generating a switching signal indicative of a video signal operating at one of a first or a second scanning frequency. A means for generating a sawtooth shaped waveform is coupled to the switching signal for switching between the first or the second scanning frequency. A means for generating an S correction signal is coupled to the source and to the sawtooth generating means. A means for filtering the parabolic signal is controllably coupled to the switching signal generator, and is also coupled to the S correction signal generating means. The filtered parabolic signal has an substantially the same shape during the first or second scanning frequency.

50 Hz parabolic signal filter

A deflection apparatus comprises a deflection amplifier coupled to a deflection waveform modulation circuit such as a diode modulator. A source for generating a modulation signal. The modulation signal comprises an AC component and a DC component, each having levels which define an amplitude ratio. An amplifier alters the amplitude ratio, and the altered amplitude ratio signal is coupled to the deflection waveform modulation circuit for deflection waveform modulation.

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Fishers, IN, United States of America

Kenneth J Helfrich