Integrating ramp analog to digital converter

Claim 2

In a analog to digital converter, the combination comprising: means for receiving said analog signal of unknown magnitude; reference signal-generating means for generating a reference signal of known magnitude; integrating means responsive to said analog signal-generating means and to said reference signal-generating means for selectively integrating said analog signal and said reference signal; indicating means for producing an output indicative of the time That has elapsed since initiation of integration of said analog signal; means for generating a signal corresponding to a selected range of integration time; comparator means responsive to said range selecting signal for producing an output signal whenever the output of said indicating means indicates that an integration time corresponding to said range signal has elapsed; and control means responsive to said comparator means output for decoupling said unknown signal and for coupling said reference signal to said integrating means.

Claim 3

A device as set forth in claim 1 wherein sequential gains of said integrator circuit correspond to predefined sequential segments of integrator time, and wherein said range selecting means includes means for establishing a threshold level, and said comparator means includes logic circuit means responsive to the analog signal integrator output attaining said threshold level for causing said comparator means output signal to be produced at the end of the said sequential time segment during which said threshold attainment occurs.

Claim 4

In a analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude, the combination comprising: means for receiving said analog signal of unknown magnitude; reference signal-generating means for generating a reference signal of known magnitude; integrating means responsive to said analog signal-generating means and to said reference signal-generating means for selectively integrating said analog signal and said reference signal; means responsive to said integrating means for generating a signal indicative of the elapsed time of the integration of said analog signal; storage means; means for loading said storage means with a signal corresponding to a selected integration time; means for sensing the contents of said storage means and said elapsed time indicating signal for producing a signal when a comparison exists therebetween; control means responsive to said sensing means signal for coupling said reference signal to said integrating means.

Claim 5

In a analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude, the combination comprising: means for receiving said analog signal of unknown magnitude; reference signal-generating means for generating a reference signal of known magnitude; integrating means responsive to said analog signal-generating means and to said reference signal-generating means for selectively integrating said analog signal and said reference signal; means responsive to said integrating means for generating a signal indicative of the elapsed time of the integration of said analog signal; storage means; means for loading said storage means with a signal corresponding to a selected integration time; means for sensing the contents of said storage means and said elapsed time indicating signal for producing a signal when a comparison exists therebetween; control means responsive to said sensing means signal for coupling said reference signal to said integrating means.

Claim 6

A device as set forth in claim 3 wherein said elapsed time indicating means comprises a counter and means for selectively gating a series of pulses to said counter.

Claim 7

A device as set forth in claim 4 wherein said storage means is a digital register; and said sensing means produces said output signal whenever at least a portion of said counter contains a count corresponding to the contents of said digital register.

Claim 8

A device as set forth in claim 1 wherein said comparator means includes a counter coupled for storing said range selecting signal, means for coupling count pulses to said counter during integration of said analog signal, and means for producing said comparator means output signal whenever the content said counter reaches a preselected level.

Claim 9

A device as set forth in claim 6 wherein said count pulses decrement said counter; and means for sensing when the count in said counter reaches zero.

Claim 10

In a analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude the combination comprising: means for receiving said analog signal of unknown magnitude; reference signal-generating means for generating a reference signal of known magnitude; integrating means responsive to said analog signal-generating means and to said reference signal-generating means for selectively integrating said analog signal and said said reference signal; pulse-producing means; means responsive to said integrating means for counting pulses from said pulse-producing means and for producing a multiplicity of carry signals during integration of said analog signal; means for generating a signal corresponding to selected range of time of integration of said analog signal; sensing means for producing an output whenever a number of said Carry signals has occurred corresponding to said range signal; and control means responsive to said sensing means output for stopping the integration of said analog signal and coupling said reference signal to said integrating means.

Claim 11

In a analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude the combination comprising: means for receiving said analog signal of unknown magnitude; reference signal-generating means for generating a reference signal of known magnitude; integrating means responsive to said analog signal-generating means and to said reference signal-generating means for selectively integrating said analog signal and said said reference signal; pulse-producing means; means responsive to said integrating means for counting pulses from said pulse-producing means and for producing a multiplicity of carry signals during integration of said analog signal; means for generating a signal corresponding to selected range of time of integration of said analog signal; sensing means for producing an output whenever a number of said Carry signals has occurred corresponding to said range signal; and control means responsive to said sensing means output for stopping the integration of said analog signal and coupling said reference signal to said integrating means.

Claim 12

A device as set forth in claim 8 wherein said means for sensing the integration of said analog signal comprises: means for detecting when the output of said integrating means reaches a threshold level; and means responsive to said detecting means and said carry signals for selectively determining the remaining length of time of integration before producing the output signal for said control means.

Claim 13

A device as set forth in claim 9 which further includes: means responsive to said pulse-producing means and said remaining integration time determining means for storing a digital count corresponding to the length of time said analog signal was integrated.