Switched mode vertical deflection system and control circuit

A switched mode vertical deflection system, comprising:

• a switched mode vertical deflection output stage for driving a vertical deflection coil;
• means for generating a feedback signal related to vertical deflection current;
• means for generating a vertical rate ramp signal;
• a comparator having an output controlling switching in said output stage and coupled for receiving said vertical rate ramp signal and said feedback signal as inputs;
• and,
• a passive network DC coupled between a source of horizontal flyback pulses and an input of said comparator for generating from energy in said horizontal flyback pulses a horizontal rate ramp signal substantially independent of amplitude variations in said flyback pulses and having a substantially constant DC voltage reference level.

A deflection system, comprising:

• a deflection output stage for driving a deflection coil;
• means for generating a feedback signal related to deflection current;
• means for generating a first deflection rate waveform;
• a passive network coupled to a source of flyback pulses for generating from energy in said flyback pulses a second deflection rate waveform substantially independent of amplitude variations in said flyback pulses and having a substantially constant DC voltage reference level set by operation of said passive network;
• and,
• a comparator coupled for receiving said first and second deflection rate waveforms and said feedback signal as inputs and having an output controlling switching in said output stage, said amplifier output having a DC voltage reference level corresponding to said DC reference level of said first deflection rate waveform.