Display power system

Claim 2

In combination: a display system including means for generating a raster scan and means for generating characters to be displayed in said display system, said character generating means being synchronized with said display means; a power supply energized with power from an input power source, said power supply providing pulses of power to said display system at a predetermined frequency; an oscillator energized with power from said power source, said display system further comprising means for synchronizing said oscillator at a harmonic of a scanning frequency of said scanning means, said oscillator driving said power supply at said harmonic frequency; and means responsive to the amount of power supplied by said power supply to said display system for varying the amount of power coupled from said power source to said power supply, said power varying means including means for filtering pulsations of said coupled power.

Claim 3

A combination in accordance with claim 1, wherein said system is a digital data display system.

Claim 4

A combination in accordance with claim 1, further comprising a power transformer to which said power supply is coupled and from which are derived a plurality of output voltages ranging from X to Y, where Y is at least 1,000X.

Claim 5

In combination: a switching mode power supply; a data display system including a cathode ray tube upon which characters are displayed in a line raster; means for the generation of a switching frequency for said power supply; a switching regulator for energizing said power supply, said switching regulator comprising a pulsing circuit and a filter, said filter providing an average value of the pulses of power generated by said pulsing circuit, said average value of power pulses being coupled to said power supply; a pulse width modulator coupled to said pulsing circuit and driven at said switching frequency, said modulator being responsive to an output voltage of said power supply for varying the width of pulses of said pulsing circuit; and means for synchronizing said switching frequency with a harmonic of said display line frequency.

Claim 6

In combination: a switching mode power supply; a data display system including a cathode ray tube upon which characters are displayed in a line raster; means for the generation of a switching frequency for said power supply; a switching regulator for energizing said power supply, said switching regulator comprising a pulsing circuit and a filter, said filter providing an average value of the pulses of power generated by said pulsing circuit, said average value of power pulses being coupled to said power supply; a pulse width modulator coupled to said pulsing circuit and driven at said switching frequency, said modulator being responsive to an output voltage of said power supply for varying the width of pulses of said pulsing circuit; and means for synchronizing said switching frequency with a harmonic of said display line frequency.

Claim 7

A combination in accordance with claim 4, wherein the means for generating said switching frequency comprises: a control oscillator for generating a squarewave output; and wherein said power supply comprises DC to AC conversion means synchronized by said control oscillator for converting said switching regulator output to ac at the control oscillator frequency.

Claim 8

A combination in accordance with claim 5, wherein the means for synchronizing the switching frequency of said supply with a multiple of the display line frequency comprises a synchronization input from said data display system.

Claim 9

A combination in accordance with claim 6, wherein said pulse width modulator includes: coupling means for coupling the squarewave output of said control oscillator to the pulse width modulator input; means for sensing current variations in said power supply output; width means for integrating the squarewave input to said pulse with modulator to form a triangular waveform; and a Schmitt trigger controlled by a particular triggering level which is supplied by said sensed output current and driven by said triangular waveform from said integrating means, whereby the pulse width of said Schmitt trigger output is a function of the level on said triangular input at which said sensing input initiates operation of said Schmitt trigger.

Claim 10

A combination in accordance with claim 7, wherein the variable pulse width output of said Schmitt trigger controls said switching regulator.

Claim 11

In combination: a cathode ray tube upon which characters are displayed in a line raster including a high voltage anode; means for generating characters on said cathode ray tube including a video amplifier for supplying both video signals and blanking signals to the cathode of said cathode ray tube; a switching mode power supply, the frequency of which is synchronized to a multiple of the line raster frequency of said cathode ray tube for supplying high voltage dc to said high voltage anode, whereby any power supply transients occur during the blanking periods of the cathode ray tube; a switching regulator for energizing said power supply, said switching regulator comprising a pulsing circuit and a filter, said filter providing an average value of the pulses of power generated by said pulsing circuit, said average value of power pulses being coupled to said power supply; and a pulse width modulator coupled to said pulsing circuit and driven at said switching frequency, said modulator being responsive to an output voltage of said power supply for varying the width of pulses of said pulsing circuit.

Claim 12

In combination: a cathode ray tube upon which characters are displayed in a line raster including a high voltage anode; means for generating characters on said cathode ray tube including a video amplifier for supplying both video signals and blanking signals to the cathode of said cathode ray tube; a switching mode power supply, the frequency of which is synchronized to a multiple of the line raster frequency of said cathode ray tube for supplying high voltage dc to said high voltage anode, whereby any power supply transients occur during the blanking periods of the cathode ray tube; a switching regulator for energizing said power supply, said switching regulator comprising a pulsing circuit and a filter, said filter providing an average value of the pulses of power generated by said pulsing circuit, said average value of power pulses being coupled to said power supply; and a pulse width modulator coupled to said pulsing circuit and driven at said switching frequency, said modulator being responsive to an output voltage of said power supply for varying the width of pulses of said pulsing circuit.