Current controlled two-state modulation
First Claim
1. Signal translation apparatus comprising,a two-state device having means for establishing a hysteresis characteristic and including an input and an output for providing one of first and second output levels and shifting to the other only in response to a predetermined shift in the level on said input across one of first and second different threshold levels,an input terminal for receiving an external signal,means for combining a current feedback signal of frequency corresponding to the rate at which the shift between said first and second levels occurs representative of the current delivered by said output with a signal related to that applied to said input terminal to provide a combined signal at the combining means output of frequency corresponding to said rate,means for coupling the output of said combining means to said input to shift said two-state device output between said first and second levels when said combined signal crosses said first and second threshold levels respectively whereby the signal at said output includes a characteristic representative of the signal at said input terminal,said output signal characteristic being its average value over a cycle,averaging means,means for coupling said two-state device output to said averaging means to provide a signal having a waveform corresponding substantially to that of the signal then received by said input terminal,said means for coupling including essentially nondissipative means for blocking spectral components of the energy at said two-state device output from said averaging means which spectral components are of frequency at least as high as the rate at which the shift between said first and second levels occurs,means for providing a voltage feedback signal representative of a signal provided by said averaging means,and means for coupling said voltage feedback signal to said means for combining to provide said combined signal that is related to said current feedback signal, the signal applied to said input terminal, and said voltage feedback signal.
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Abstract
In a current controlled two-state modulation system having a power switch and a low pass filter, a current sensor provides a current feedback signal representative of the current delivered by the power switch to the low pass filter. The low pass filter also provides a voltage feedback signal that is combined with a reference signal to provide a combined signal. A limiting amplifier amplifies the combined signal for further combination with the current feedback signal to provide a switching signal that is delivered to a circuit characterized by hysteresis. This circuit determines the instant when the power switch is switched so as to maintain the output voltage provided by the low pass filter substantially constant so long as the load current is less than a predetermined limiting value determined by the limiting amplifier and thereafter limits the output current to substantially the predetermined limiting value.
167 Citations
19 Claims
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1. Signal translation apparatus comprising,
a two-state device having means for establishing a hysteresis characteristic and including an input and an output for providing one of first and second output levels and shifting to the other only in response to a predetermined shift in the level on said input across one of first and second different threshold levels, an input terminal for receiving an external signal, means for combining a current feedback signal of frequency corresponding to the rate at which the shift between said first and second levels occurs representative of the current delivered by said output with a signal related to that applied to said input terminal to provide a combined signal at the combining means output of frequency corresponding to said rate, means for coupling the output of said combining means to said input to shift said two-state device output between said first and second levels when said combined signal crosses said first and second threshold levels respectively whereby the signal at said output includes a characteristic representative of the signal at said input terminal, said output signal characteristic being its average value over a cycle, averaging means, means for coupling said two-state device output to said averaging means to provide a signal having a waveform corresponding substantially to that of the signal then received by said input terminal, said means for coupling including essentially nondissipative means for blocking spectral components of the energy at said two-state device output from said averaging means which spectral components are of frequency at least as high as the rate at which the shift between said first and second levels occurs, means for providing a voltage feedback signal representative of a signal provided by said averaging means, and means for coupling said voltage feedback signal to said means for combining to provide said combined signal that is related to said current feedback signal, the signal applied to said input terminal, and said voltage feedback signal.
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8. Signal translation apparatus comprising,
an output terminal, sources of first and second output signal levels, a switching signal terminal, switching means for coupling said first and said second output signal levels to said output terminal during mutually exclusive time intervals in response to a predetermined shift in the level of a switching signal on said switching signal terminal across one of first and second different threshold levels, an input terminal for receiving an input signal, combining means for providing said switching signal by combining a signal related to that on said input terminal with a current feedback signal, feedback means responsive to the current delivered from said sources through said switching means to said output terminal for providing said current feedback signal representative of said current with cyclical variations synchronously related to those of said current delivered to said output terminal, averaging means coupled to said output terminal for providing a signal related to the ratio of time said first signal level is provided on said output terminal to the time said second signal level is provided on said output terminal, means for providing a voltage feedback signal representative of a signal provided by said averaging means, and means for coupling said voltage feedback signal to said combining means to provide said switching signal of frequency the same as said cyclical variations that is related to that on said input terminal, said current feedback signal and said voltage feedback signal for establishing said first and second output levels on said output terminal when said switching signal crosses said first and second threshold levels respectively.
Specification