Differential readout of a pixel array with elimination of pixel- and column-wise fixed pattern noise
First Claim
1. An amplifying circuit, comprising:
- an amplifying element with at least an input terminal and an output terminal;
a signal input node, the signal levels of which at least two moments in time are to be amplified by the amplifying element;
at least two connecting lines between the signal input node and the amplifying element, for transferring a signal from the signal input node to the input terminal of the amplifying element;
a memory element on at least one of the connecting lines, for storing a signal level of the signal input node at a moment in time;
an input switching element disposed one each connecting line, between the memory element and the input terminal of the amplifying element if a memory element is provided on the connecting line, for consecutively connecting signal levels of the signal input node at different moments in time to the same amplifying element;
a first output switching element coupled to the output terminal of the amplifying element;
a second output switching element coupled to the output terminal of the amplifying element without connection through the first output switching element;
a first readout bus coupled to the first output switching element;
a second readout bus coupled to the second output switching element; and
an output amplifier coupled to the first and second readout buses.
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Accused Products
Abstract
The present invention discloses an amplifying circuit, comprising an amplifying element with at least an input terminal and an output terminal. A signal input node is provided, the signal levels of which at least two moments in time are to be amplified by the amplifying element. At least two connecting lines are provided between the signal input node and the amplifying element, for transferring a signal from the signal input node to the input terminal of the amplifying element. A memory element is located on at least one of the connecting lines, for storing a signal level of the signal input node at a moment in time, and a switching element is disposed on each connecting line, between the memory element and the input terminal of the amplifying element if a memory element is provided on the connecting line, for consecutively connecting signal levels of the signal input node at different moments in time to the same amplifying element. The amplifying circuit has at least one output node, each output node being connected to the output terminal of the same amplifying element.
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Citations
20 Claims
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1. An amplifying circuit, comprising:
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an amplifying element with at least an input terminal and an output terminal; a signal input node, the signal levels of which at least two moments in time are to be amplified by the amplifying element; at least two connecting lines between the signal input node and the amplifying element, for transferring a signal from the signal input node to the input terminal of the amplifying element; a memory element on at least one of the connecting lines, for storing a signal level of the signal input node at a moment in time; an input switching element disposed one each connecting line, between the memory element and the input terminal of the amplifying element if a memory element is provided on the connecting line, for consecutively connecting signal levels of the signal input node at different moments in time to the same amplifying element; a first output switching element coupled to the output terminal of the amplifying element; a second output switching element coupled to the output terminal of the amplifying element without connection through the first output switching element; a first readout bus coupled to the first output switching element; a second readout bus coupled to the second output switching element; and an output amplifier coupled to the first and second readout buses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An array of amplifying circuits, each amplifying circuit, comprising:
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an amplifying element with at least an input terminal and an output terminal; a signal input node, the signal levels of which at least two moments in time are to be amplified by the amplifying element; at least two connecting lines between the signal input node and the amplifying element, for transferring a signal from the signal input node to the input terminal of the amplifying element; a memory element on at least one of the connecting lines, for storing a signal level of the signal input node at a moment in time; a switching element disposed on each connecting line, between the memory element and the input terminal of the amplifying element if a memory element is provided on the connecting line, for consecutively connecting signal levels of the signal input node at different moments in time to the same amplifying element; a first output switching element coupled to the output terminal of the amplifying element; a second output switching element coupled to the output terminal of the amplifying element without connection through the first output switching element; a first readout bus coupled to the first output switching element; a second readout bus coupled to the second output switching element; and an output amplifier coupled to the first and second readout buses, wherein the first and second readout buses are coupled to each of the array of amplifying circuits.
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10. A device for imaging applications, comprising:
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a matrix of active pixels arranged in a geometric configuration, each pixel producing an electrical signal indicative of the light intensity of a portion of a scene being imaged by that pixel; at least one amplifying circuit common to a group of pixels out of the matrix, wherein each amplifying circuit comprises; an amplifying element with at least an input terminal and an output terminal; a signal input node being intended to obtain electrical signals from pixels out of the group of pixels to which the amplifying circuit is common, the signal levels of which are to be amplified by the amplifying element; at least two connecting lines between the signal input node and the amplifying element, for transferring an electrical signal from the signal input node to the input terminal of the amplifying element; a memory element on at least one of the connecting lines, for storing a signal level of the electrical signal at the signal input node at a moment in time; a switching element disposed on each connecting line, between the memory element and the input terminal of the amplifying element if a memory element is provided on the connecting line, for consecutively connecting signal levels of the electrical signals at the signal input node at different moments in time to the same amplifying element; a first output switching element coupled to the output terminal of the amplifying element; a second output switching element coupled to the output terminal of the amplifying element; a first readout bus coupled to the first output switching element; a second readout bus coupled to the second output switching element without connection through the first output switching element; and an output amplifier coupled to the first and second readout buses, wherein the first and second readout buses are coupled to each amplifying circuit. - View Dependent Claims (11, 12, 13)
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14. A method for reducing fixed pattern noise of solid state imaging device having a group of active pixels, each pixel comprising a radiation sensitive element and an amplifying circuit, the method comprising:
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reading out the signal of a pixel brought in a first state and storing the corresponding voltage level in a first memory element; reading out the signal of the pixel brought in a second state, which is different from the first state, and storing the corresponding voltage level in a second memory element; transferring the signal of the first memory element to an amplifying element, amplifying the signal of the first memory element, and transferring the amplified signal of the first memory element to a first readout bus; transferring the signal of the second memory element to the same amplifying element, amplifying the signal of the first memory element, and transferring the amplified signal of the second memory element to a second readout bus in parallel with the transfer to the amplified signal of the first memory element to the first readout bus; and repeating these steps for at least part of the pixels of the imaging device. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification