Deflection supply voltage feedback control in conjunction with frequency change

A video display apparatus, comprising:

• a deflection circuit output stage for selectively generating a deflection current in a deflection winding at a first deflection frequency and at a second deflection frequency;
• a power supply having a power transformer for producing a first supply voltage to energize said deflection circuit output stage, selectively, when said first deflection frequency is selected, and for producing a second supply voltage to energize said deflection circuit output stage, selectively, when said second deflection frequency is selected, said power transformer including a transformer winding for producing a third supply voltage that is coupled to a load circuit;
• and
• a power supply regulator responsive to at least one of said first and second supply voltages for regulating at least one of said first and second supply voltages via a negative feedback path such that a volts-per-turn ratio in said transformer winding remains the same at each of said first and second deflection frequencies.

A deflection arrangement, comprising:

• a power supply for producing a first deflection voltage when said deflection arrangement operates at a first deflection frequency and for producing a second deflection voltage when said deflection arrangement operates at a second deflection frequency, different from said first deflection frequency, said power supply also including feedback by way of a feedback path, which feedback tends to control that one of said first and second deflection voltages being generated;
• feedback control means coupled to said feedback path, for controlling said feedback to be in a first proportion when said first deflection frequency is selected and in a second proportion, different from said first proportion, when said second deflection frequency is selected, for tending to maintain a set voltage value;
• and
• voltage correction means coupled to said feedback path, for adding a first voltage correction signal to said feedback when said first deflection frequency is selected, and for adding to said feedback a second voltage correction signal, different from said first voltage correction signal, when said second deflection frequency is selected, for correcting the value of said set voltage.

A power supply, comprising:

• a controllable source of varying voltage including a feedback input port;
• a transformer including first, second, and third secondary windings, and also including a primary winding coupled to said controllable source, for generating pulsatory voltages in said first, second, and third secondary windings;
• rectifying and filtering means coupled to said first secondary winding, for generating a first energizing voltage;
• second and third rectifying means coupled to said second and third secondary windings, respectively, for rectifying said pulsatory voltages developed across said second and third secondary windings, respectively;
• second filtering means, for smoothing rectified pulsatory voltages for producing a second energizing voltage;
• a switch coupled to said second and third rectifying means and to said second filtering means, for, in a first mode of operation, coupling said second rectifying means to said second filtering means, to the exclusion of said third rectifying means, and for, in a second mode of operation, coupling said third rectifying means to said second filtering means;
• and
• feedback means coupled to said second filtering means and to said feedback input port of said source of varying voltage for, in said first mode of operation, coupling to said feedback input port a first proportion of said second energizing voltage, and for, in said second mode of operation, coupling to said feedback input port a second proportion, different from said first proportion, of said second energizing voltage.

A power supply, comprising:

• a switch mode power supply including a transformer and first, second, and third secondary windings, for producing first, second and third secondary voltages;
• first rectifying and filtering means coupled to receive said first secondary voltage for producing a first energizing voltage;
• second and third rectifying means coupled to said second and third secondary windings, respectively, for rectifying said second and third secondary voltages for generating second and third rectified secondary voltages;
• second filtering means for smoothing rectified secondary voltages to produce a second energizing voltage;
• controllable switch means coupled to said second and third rectifying means and to said second filtering means, for, in a first mode of operation, coupling said second rectified secondary voltage from said second rectifying means to said second filtering means, to the exclusion of said third rectified secondary voltage, and for, in a second mode of operation, coupling said third rectified secondary voltage to said second filtering means;
• and
• controllable feedback means coupled to said second filtering means and to said switch mode power supply, for coupling a sample of the smoothed voltage produced by said second filtering means to said switch mode power supply for feedback control thereof, said sample being in a first proportion of said smoothed voltage in said first operating mode and in a second proportion, different from said first proportion, in said second operating mode.