Technique for reduction of electrical input noise in charge coupled devices

Claim 1

In a charge coupled device comprising a semiconductor substrate defining a channel and phase electrodes overlying and insulated from a surface of said substrate along said channel, input structure for introducing charge packets into a potential well in said substrate beneath at least one of said phase electrodes under control of input signals applied to said input structure, output structure for deriving output signals from said channel, and means for applying clock voltages to said phase electrodes for propagating said electrical charge packets along said substrate beneath said phase electrodes toward said output structure, said input structure including: means for defining a floating doped region having conductivity different from that of said channel, means for introducing an input signal charge packet into said floating doped region dependent on the amplitude of an input signal applied to said input structure, said input signal charge packet characterized by noise uncertainty factor KTC wherein k = Boltzman's constant; T = absolute temperature; C = capacitance associated with said floating doped region; gate electrode means overlying and insulated from said substrate and disposed between said floating doped region and said one phase electrode; means for applying a gating voltage to said gate electrode and a clock voltage to said one phase electrode to transfer a quantity of charge dependent on the magnitude of said input signal from said floating doped region into the potential well under said one phase electrode, said quantity of charge also characterized by said noise uncertainty factor; means for sampling the voltage of said floating doped region after introduction thereto of said input signal charge packet, and for sensing the voltage of said floating doped region subsequent to said transfer of charge into said potential well and for deriving from said sensed voltages an error voltage characteristic of the said noise uncertainty factor kTC; and means for utilizing said error voltage to modify an output signal produced by said output structure responsive to said input signal to produce an output signal voltage substantially free from said noise uncertainty factor.

Claim 8

A method of reducing noise content in an output signal from output structure of a charge coupled device which comprises a semiconductor substrate defining a channel and having an insulating layer on one surface of said substrate and a plurality of spaced apart phase electrodes disposed on said insulating layer above said channel, and input structure for introducing electrical charges into said charge coupled device for propagation along said channel to said output structure, comprising the steps of introducing into a floating doped region in said substrate adjacent to and spaced from a first one of said phase electrodes, a quantity of electrical charge dependent on the amplitude of an input signal applied to said input structure, said quantity of charge being characterized by noise uncertainty factor kTC wherein k = Boltzman's constant; T = absolute temperature; C = capacitance associated with said floating doped region; sampling the voltage of said floating doped region after introduction of said quantity of charge; applying a gating voltage to a gate electrode located on said insulating layer between said floating doped region and said first phase electrode and a clock voltage to said first phase electrode to transfer a quantity of electrical charge dependent on the amplitude of said input signal from said floating doped region into a potential well beneath said first phase electrode, said electrical charge also being characterized by said noise uncertainty factor; sensing the voltage of said floating doped region following said transfer of electrical charge; utilizing said sensed voltages to generate an error voltage dependent on said noise uncertainty factor, propagating said charge inputted into said potential well along said channel to said output structure to generate an output signal characterized by said noise uncertainty factor, and utilizing said error signal to modify said output signal to reduce said noise uncertainty factor thereof.

Claim 9

A method of reducing noise content in an output signal from output structure of a charge coupled device which comprises a semiconductor substrate defining a channel and having an insulating layer on one surface of said substrate and a plurality of spaced apart phase electrodes disposed on said insulating layer above said channel, and input structure for introducing electrical charges into said charge coupled device for propagation along said channel to said output structure, comprising the steps of introducing into a floating doped region in said substrate adjacent to and spaced from a first one of said phase electrodes, a quantity of electrical charge dependent on the amplitude of an input signal applied to said input structure, said quantity of charge being characterized by noise uncertainty factor kTC wherein k = Boltzman's constant; T = absolute temperature; C = capacitance associated with said floating doped region; sampling the voltage of said floating doped region after introduction of said quantity of charge; applying a gating voltage to a gate electrode located on said insulating layer between said floating doped region and said first phase electrode and a clock voltage to said first phase electrode to transfer a quantity of electrical charge dependent on the amplitude of said input signal from said floating doped region into a potential well beneath said first phase electrode, said electrical charge also being characterized by said noise uncertainty factor; sensing the voltage of said floating doped region following said transfer of electrical charge; utilizing said sensed voltages to generate an error voltage dependent on said noise uncertainty factor, propagating said charge inputted into said potential well along said channel to said output structure to generate an output signal characterized by said noise uncertainty factor, and utilizing said error signal to modify said output signal to reduce said noise uncertainty factor thereof.