Analog-to-digital conversion and associated circuitry

Claim 2

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the generating means comprising an operational amplifier with capacitive feedback for generating said ramp signal, a current source for feeding said operational amplifier, and gating means for controllably resetting said operational amplifier to initiate the generation of said ramp signal thereby, the said current source comprising an inverter amplifier constituted of a complementary metaloxide-silicon device, a ramp-slope capacitor connected to the input of said invented amplifier, and a metal-oxide-silicon resistor connected at the output of said inverter amplifier.

Claim 3

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the generating means comprising an operational amplifier with capacitive feedback for generating said ramp signal, a current source for feeding said operational amplifier, and gating means for controllably resetting said operational amplifier to initiate the generation of said ramp signal thereby, further including gating means for controlling the charge and discharge of said ramp-slope capacitor to adjust the slope of said ramp signal, said gating means comprising a first metal-oxide-silicon gate for controlling the charge of said ramp-slope capacitor and a second metal-oxide-silicon gate for controlling the discharge of said ramp-slope capacitor.

Claim 4

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the generating means comprising an operational amplifier with capacitive feedback for generating said ramp signal, a current source for feeding said operational amplifier, and gating means for controllably resetting said operational amplifier to initiate the generation of said ramp signal thereby, further including gating means for controlling the charge and discharge of said ramp-slope capacitor to adjust the slope of said ramp signal, said gating means comprising a first metal-oxide-silicon gate for controlling the charge of said ramp-slope capacitor and a second metal-oxide-silicon gate for controlling the discharge of said ramp-slope capacitor.

Claim 5

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the providing means comprising means for comparing said ramp signal with said first presecribed level and said second prescribed level and to generate, at respective coincidences thereof, said first control signal and said second control signal, said first prescribed level is being preset in a first comparator by a signal related to said analog input signal and said second prescribed level is being preset in a second comparatoR by a signal related to said input signal, each comparator comprising means for indicating, at an output, the existence of a difference between signals at distinctive inputs thereof, storage means connected to one of the inputs of the difference indicating means, and means for gating said output to said storage means to preset said comparator with a signal related to a signal applied at the other input thereof. the difference indicating means comprising first and second differentially connected metal-oxide-silicon devices, a third metal-oxide-silicon device disposed in series with the first and adapted to act as a resistor of high resistive magnitude, and a fourth metal-oxide-silicon device connected jointly to the first and second devices and adapted to act, in conjunction with a voltage source, as a current source.

Claim 6

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the providing means comprising means for comparing said ramp signal with said first presecribed level and said second prescribed level and to generate, at respective coincidences thereof, said first control signal and said second control signal, said first prescribed level is being preset in a first comparator by a signal related to said analog input signal and said second prescribed level is being preset in a second comparatoR by a signal related to said input signal, each comparator comprising means for indicating, at an output, the existence of a difference between signals at distinctive inputs thereof, storage means connected to one of the inputs of the difference indicating means, and means for gating said output to said storage means to preset said comparator with a signal related to a signal applied at the other input thereof. the difference indicating means comprising first and second differentially connected metal-oxide-silicon devices, a third metal-oxide-silicon device disposed in series with the first and adapted to act as a resistor of high resistive magnitude, and a fourth metal-oxide-silicon device connected jointly to the first and second devices and adapted to act, in conjunction with a voltage source, as a current source.

Claim 7

Apparatus as defined in claim 3 wherein said first and second metal-oxide-silicon devices are disposed to achieve a common electrode by a separate, diffused region constituting a well in a base of semiconductor material.

Claim 8

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the providing means comprising means for comparing said ramp signal with said first prescribed level and said second prescribed level and to generate, at respective coincidences thereof, said first control signal and said second control signal, said first prescribed level is being preset in a first comparator by a signal related to said analog input signal and said second prescribed level being preset in a second comparator by a signal related to said input signal each comparator comprising means for indicating, at an output, the existence of a difference between signals at distinctive inputs thereof, storage means connected to one of the inputs of the difference indicating means, and means for gating said output to said storage means to preset said comparator with a signal related to a signal applied at the other input thereof an amplifier being connected between the output of said difference indicating means and gating means a compensating network for preventing undesired oscillations by damping natural frequencies of said comparator said compensating network including a switchable resistance unit comprising a controllable metal-oxide-silicon device which is operative during the storage of signals on said storage means and inoperative thereafter in order to enhance the speed of operation of said comparator.

Claim 9

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the providing means comprising means for comparing said ramp signal with said first prescribed level and said second prescribed level and to generate, at respective coincidences thereof, said first control signal and said second control signal, said first prescribed level is being preset in a first comparator by a signal related to said analog input signal and said second prescribed level being preset in a second comparator by a signal related to said input signal each comparator comprising means for indicating, at an output, the existence of a difference between signals at distinctive inputs thereof, storage means connected to one of the inputs of the difference indicating means, and means for gating said output to said storage means to preset said comparator with a signal related to a signal applied at the other input thereof an amplifier being connected between the output of said difference indicating means and gating means a compensating network for preventing undesired oscillations by damping natural frequencies of said comparator said compensating network including a switchable resistance unit comprising a controllable metal-oxide-silicon device which is operative during the storage of signals on said storage means and inoperative thereafter in order to enhance the speed of operation of said comparator.

Claim 10

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the producing means comprising an oscillator which is started and stopped by said control signals, and means for counting the outpUt of said oscillator, said oscillator comprising a feedback amplifier formed by a plurality of complementary metal-oxide-silicon devices, a plurality of metal-oxide-silicon control devices, one connected in series with one of said complementary metal-oxide-silicon devices and another connected in shunt therewith, and a control line for stopping said oscillator by applying a signal to open the first control device and close the second.

Claim 11

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof; means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the producing means comprising an oscillator which is started and stopped by said control signals, and means for counting the outpUt of said oscillator, said oscillator comprising a feedback amplifier formed by a plurality of complementary metal-oxide-silicon devices, a plurality of metal-oxide-silicon control devices, one connected in series with one of said complementary metal-oxide-silicon devices and another connected in shunt therewith, and a control line for stopping said oscillator by applying a signal to open the first control device and close the second.

Claim 12

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof, means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the producing means comprising an oscillator which is started and stopped by said control signals, and means for counting the output of said oscillator; the counting means being comprised of a plurality of stages, each comprising a first switching device having signal and control terminals, a second switching device having signal and control terminals, an inverter interconnecting like signal terminals of the two switching devices, storage means jointly connecting other like signal terminals of said devices, and means connected to the control terminals of said switching devices for causing an interchange of said signal states.

Claim 13

Apparatus for converting analog input signals into digital output signals, comprising means for generating a ramp signal and adjusting the slope thereof, means for providing a first control signal when said ramp signal reaches a first prescribed level and a second control signal when said ramp signal reaches a second prescribed level, at least one of the levels being determined by an analog input signal; means responsive to the two control signals for producing digital output signals in accordance with the time interval between the occurrence of the first and second control signals; and means for testing the slope of said ramp signal and controlling the adjustment thereof, the producing means comprising an oscillator which is started and stopped by said control signals, and means for counting the output of said oscillator; the counting means being comprised of a plurality of stages, each comprising a first switching device having signal and control terminals, a second switching device having signal and control terminals, an inverter interconnecting like signal terminals of the two switching devices, storage means jointly connecting other like signal terminals of said devices, and means connected to the control terminals of said switching devices for causing an interchange of said signal states.

Claim 14

Apparatus as defined in claim 7 wherein each of said switching devices is a pair of back-to-back metal-oxide-silicon devices and said storage means is a capacitor.

Claim 15

Apparatus as defined in claim 8 further including a metal-oxide-silicon device for resetting said switching devices.