Abstract: A video display includes a scanner operable at a first frequency and a higher second frequency. A switch mode power supply drives a transformer with three secondaries. First and second rectifiers & filters are associated with the first and second secondaries. A rectifier is coupled to the third secondary and by way of a switch to the first filter. Feedback from the first filter controls the SMPS. In a first operating mode, the scanner is operated at the first frequency, the switch is open, the scanner supply is a first voltage from the first filter, and ancillary equipment is supplied with a third voltage by the second filter. In a second operating mode, the scanner is operated at the second frequency, the switch is closed, the scanner supply is a second voltage, higher than the first, from the first filter, and ancillary equipment is supplied with the same third voltage.

Abstract: An autotransformer steps up the output of a high voltage amplifier for applying a drive signal to the focus electrode of a CRT. A parabolic signal is obtained or generated at a deflection frequency such as the horizontal scanning frequency and is applied as an input to the amplifier. The amplifier output is coupled to a center tap of the autotransformer. One winding is serially coupled to the focus electrode and the other winding is AC coupled by a capacitor to ground, in parallel with the amplifier output. The transformer steps up the amplifier output voltage and can reduce the voltage rating required of transistors in the amplifier.

Abstract: A dynamic focus voltage generator includes a source of a flyback input signal at a horizontal deflection frequency. A double integrator is responsive to the input signal for generating a parabolic periodic signal. An amplitude detector is responsive to the parabolic periodic signal for generating a control signal that is indicative of an amplitude of the parabolic periodic signal. A comparator is responsive to a signal at a reference level and to the control signal and coupled to the double integrator for regulating an amplitude of the parabolic periodic signal in a gain control negative feedback manner. A non-linear network is responsive to the parabolic periodic signal for producing a bathtub shaped output signal that is coupled to a focus electrode of a cathode ray tube.

Abstract: An autotransformer steps up the output of a high voltage amplifier for applying a drive signal to the focus electrode of a CRT. A parabolic signal is obtained or generated at a deflection frequency such as the horizontal scanning frequency and is applied as an input to the amplifier. The amplifier output is coupled to a center tap of the autotransformer. One winding is serially coupled to the focus electrode and the other winding is AC coupled by a capacitor to ground, in parallel with the amplifier output. The transformer steps up the amplifier output voltage and can reduce the voltage rating required of transistors in the amplifier.

Abstract: A dynamic focus voltage generator includes a source of a flyback input signal at a horizontal deflection frequency. A double integrator is responsive to the input signal for generating a parabolic periodic signal. An amplitude detector is responsive to the parabolic periodic signal for generating a control signal that is indicative of an amplitude of the parabolic periodic signal. A comparator is responsive to a signal at a reference level and to the control signal and coupled to the double integrator for regulating an amplitude of the parabolic periodic signal in a gain control negative feedback manner. A non-linear network is responsive to the parabolic periodic signal for producing a bathtub shaped output signal that is coupled to a focus electrode of a cathode ray tube.

Abstract: In a television deflection system employing a first SCR for coupling a deflection winding across a source of energy during a trace interval of each deflection cycle and a second SCR for replenishing energy to the source of energy during a commutation interval of each deflection cycle, a gating circuit for triggering the first SCR. The gating circuit employs a voltage divider coupled in parallel with the second SCR which develops gating signals proportional to the voltage across the second SCR.