Power Supply for a deflection circuit operating at multi-scan frequencies
First Claim
1. A video display deflection apparatus capable of selectively operating at a deflection frequency selected from a range of frequencies, comprising:
- a source of a synchronization signal at a frequency indicative of said selected frequency;
a deflection circuit output stage responsive to said synchronization signal for generating a deflection current at said selected deflection frequency;
a first power supply including a first power transistor for generating a first supply voltage by the operation of said first power transistor when a first deflection frequency is selected;
a second power supply including a second power transistor for generating a second supply voltage by the operation of said second power transistor when a second deflection frequency is selected; and
a source of a signal indicative of said frequency of said synchronization signal for generating a first control signal that is coupled to one of said first and second power supplies for selecting, in accordance therewith, said first supply voltage to energize said deflection circuit output stage, when said first deflection frequency is selected, and said second supply voltage, when said second deflection frequency is selected, such that when said first supply voltage energizes said output stage, said second power transistor is outside a supply current path of said output stage, and, when said second supply voltage energizes said output stage, said first power transistor is outside said supply current path of said output stage.
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Accused Products
Abstract
A television apparatus set has the capability of selectively displaying picture information obtained from a broadcast television signal and a display monitor data signal. A zero voltage switching switch mode power supply generates a higher voltage B+ supply voltage for a horizontal deflection circuit output stage, when the deflection circuit output stage operates at a rate greater than or equal to approximately 32 KHz. A series-pass regulator power supply generates at a common supply terminal a lower voltage B+ supply voltage, when the deflection circuit output stage operates at a lower rate equal to approximately 16 KHz. During a start-up interval, the horizontal scanning output stage is supplied with the lower B+ supply voltage regardless of the scan frequency for reducing excessive stress in the horizontal output stage switching transistor to improve reliability.
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Citations
13 Claims
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1. A video display deflection apparatus capable of selectively operating at a deflection frequency selected from a range of frequencies, comprising:
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a source of a synchronization signal at a frequency indicative of said selected frequency; a deflection circuit output stage responsive to said synchronization signal for generating a deflection current at said selected deflection frequency; a first power supply including a first power transistor for generating a first supply voltage by the operation of said first power transistor when a first deflection frequency is selected; a second power supply including a second power transistor for generating a second supply voltage by the operation of said second power transistor when a second deflection frequency is selected; and a source of a signal indicative of said frequency of said synchronization signal for generating a first control signal that is coupled to one of said first and second power supplies for selecting, in accordance therewith, said first supply voltage to energize said deflection circuit output stage, when said first deflection frequency is selected, and said second supply voltage, when said second deflection frequency is selected, such that when said first supply voltage energizes said output stage, said second power transistor is outside a supply current path of said output stage, and, when said second supply voltage energizes said output stage, said first power transistor is outside said supply current path of said output stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A video display deflection apparatus capable of selectively operating at a deflection frequency selected from a range of frequencies, comprising:
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a source of a synchronization signal at a frequency indicative of said selected frequency; a deflection circuit output stage responsive to said synchronization signal for generating a deflection current at said selected deflection frequency; a first power supply for generating a first supply voltage when a first deflection frequency is selected; a second power supply for generating a second supply voltage when a second deflection frequency is selected; and a source of a signal indicative of a frequency of said synchronization signal for generating a first control signal that is coupled to one of said first and second power supplies for selecting, in accordance therewith, said first supply voltage to energize said deflection circuit output stage, when said first deflection frequency is selected, and said second supply voltage, when said second deflection frequency is selected, such that during a start-up interval, one of said first and said second supply voltages having a lower voltage is selected to energize said deflection circuit output stage regardless of the selected frequency.
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Specification