Design and operation of a floating gate amplifier

Wen, David D.

doi:10.1109/jssc.1974.1050535

Cited by 56 publications

(15 citation statements)

References 5 publications

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“…A distinctive feature of the Skipper CCD is its floating gate output stage [6,9] that allows for non destructive charge measurements, instead of the common floating diffusion output stage used in standard CCDs. The layout of the output stage of the L2 amplifier is shown in Fig.…”

Section: Skipper Ccd Detectormentioning

confidence: 99%

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Sub-electron readout noise in a Skipper CCD fabricated on high resistivity silicon

et al. 2012

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The readout noise for Charge-Coupled Devices (CCDs) has been the main limitation when using these detectors for measuring small amplitude signals. A scientific CCD fabricated on a high-resistivity silicon substrate utilizing a floating gate amplifier with the capability of multiple sampling of the charge signal is described in this paper. The Skipper CCD architecture and its Exp Astron (2012) 34:43-64 advantages for low noise applications are discussed. A technique for obtaining sub-electron readout noise levels is presented, and its noise and signal characteristics are derived. We demonstrate that with this procedure a very low readout noise of 0.2e − RMS can be achieved. The contribution of other noise sources (output stage, vertical and horizontal charge transfer inefficiency, and dark current noise) are also considered. The optimum number of samples for achieving the total lowest possible noise level is obtained. This technique is applied to an X-rays experiment using a 55 Fe source.

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Section: Skipper Ccd Detectormentioning

confidence: 99%

“…The signal charge induces a potential change on the floating gate electrode that is sensed by the output transistor. The change in voltage at the floating gate for a given amount of signal charge Q is given by [9,10] …”

Section: Floating Gate Output Stagementioning

confidence: 99%

Sub-electron readout noise in a Skipper CCD fabricated on high resistivity silicon

et al. 2012

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“…Electrons are photoemitted from a zinc film into the vacuum above the device [27] and attracted to the channels by a positive bias on the large right or left reservoir gates. Figure 1 illustrates the layout and functionality of the device's array of gates and channels.Electrons are detected nondestructively through their capacitive coupling to the sense gate (a method similar to the floating-gate amplifiers employed in early Si-CCDs [28]). The electrons' coupling to the sense gate is modulated as they are pushed over it and pulled away by a constant ac-voltage (V ac ) applied to the neighboring twiddle gate of 400 mV pp .…”

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confidence: 99%

“…Electrons are detected nondestructively through their capacitive coupling to the sense gate (a method similar to the floating-gate amplifiers employed in early Si-CCDs [28]). The electrons' coupling to the sense gate is modulated as they are pushed over it and pulled away by a constant ac-voltage (V ac ) applied to the neighboring twiddle gate of 400 mV pp .…”

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confidence: 99%

Electrons Take Their Places on a Liquid Helium Grid

Kono¹

2011

Physics

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Unprecedented transport efficiency is demonstrated for electrons on the surface of micron-scale superfluid helium-filled channels by co-opting silicon processing technology to construct the equivalent of a charge-coupled device. Strong fringing fields lead to undetectably rare transfer failures after over a billion cycles in two dimensions. This extremely efficient transport is measured in 120 channels simultaneously with packets of up to 20 electrons, and down to singly occupied pixels. These results point the way towards the large scale transport of either computational qubits or electron spin qubits used for communications in a hybrid qubit system. DOI: 10.1103/PhysRevLett.107.266803 PACS numbers: 73.40.Àc, 67.25.bh, 73.20.Àr Interesting applications of quantum algorithms will need large numbers of logical qubits, as well as the many-fold redundancy of corresponding physical qubits required for quantum error correction [1]. While experiments have shown several simple quantum systems to have qubit coherence times exceeding the time necessary for performing operations [2][3][4][5][6], thus far none have demonstrated scaling beyond a handful of coupled qubits.Electrons floating on the surface of liquid helium have very little interaction with the environment, resulting in long predicted spin coherence times [7]. The minute spinorbit interaction means that even mobile electrons are expected to exhibit long spin coherence, unique amongst condensed matter systems. Electron spin-based solid-state qubits normally require the electrons to be confined, i.e., in a quantum dot [8] or bound to a donor [9], to obtain acceptable spin coherence [6]. Coherent mobile spins will enable fast and efficient qubit transport. Here we demonstrate exceptionally efficient clocked electron transport along gate-defined paths across the surface of superfluid helium (spin coherence during transport has not yet been measured). The gates form the equivalent of a buriedchannel charge-coupled device (CCD) [10], which simultaneously moves electron packets in many parallel channels (120 channels in the structure used for this work). No transfer errors were detected after clocking the electron packets across 10 9 pixels (moving them 9 km), even with one electron per packet, on average. This highly parallel and efficient electron transport could be leveraged in a hybrid quantum processor to form a quantum communications fabric between computational qubits defined and localized in the substrate, for example, superconducting qubits [11]. Alternatively, the same electron spin qubits could be used for both communications and computation [7].Electrons are held above the surface of superfluid helium by the fields from underlying electrostatic gates (in addition to a weak image potential) and their positions can be controlled by voltages applied to those gates [12][13][14][15]. They form a clean and well-studied classical two-dimensional electron system. Besides being the highest mobility twodimensional electron system [16] and forming the first demo...

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“…Here, we a r e u s i n g a g a t e for the sense as opposed to the di usion. The idea here is to use a similar technique as in the oating di usion case, except now w e rely on the capacitive coupling to a gate for the charge sense 45,46]. The advantage of this approach is that the charge is not removed in the process and can continue on down the shift register, where there may be more oating gate ampli ers.…”

Section: Charge Outputmentioning

confidence: 99%

An analog VLSI chip for estimating the focus of expansion

McQuirk

Lee²,

Horn³

1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers

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For applications involving the control of moving vehicles, the recovery of relative motion between a camera and its environment is of high utility. This thesis describes the design and testing of a real-time analog vlsi chip which estimates the focus of expansion (foe) f r o m measured time-varying images. Our approach assumes a camera moving through a xed world with translational velocity the foe is the projection of the translation vector onto the image plane. This location is the point t o wards which the camera is moving, and other points appear to be expanding outward from. By way of the camera imaging parameters, the location of the foe gives the direction of 3-D translation.The algorithm we use for estimating the foe minimizes the sum of squares of the di erences at every pixel between the observed time variation of brightness and the predicted variation given the assumed position of the foe. This minimization is not straightforward, because the relationship between the brightness derivatives depends on the unknown distance to the surface being imaged. However, image points where brightness is instantaneously constant play a critical role. Ideally, the foe would be at the intersection of the tangents to the iso-brightness contours at these \stationary" points. In practice, brightness derivatives are hard to estimate accurately given that the image is quite noisy. Reliable results can nevertheless be obtained if the image contains many stationary points and the point is found that minimizes the sum of squares of the perpendicular distances from the tangents at the stationary points.The foe chip calculates the gradient of this least-squares minimization sum, and the estimation is performed by closing a feedback loop around it. The chip has been implemented using an embedded ccd imager for image acquisition and a row-parallel processing scheme. A 64 64 version was fabricated in a 2 m ccd/bicmos process through mosis with a design goal of 200 mW of on-chip power, a top frame rate of 1000 frames/second, and a basic accuracy of 5%. A complete experimental system which estimates the foe in real time using real motion and image scenes is demonstrated.

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Design and operation of a floating gate amplifier

Cited by 56 publications

References 5 publications

Sub-electron readout noise in a Skipper CCD fabricated on high resistivity silicon

Sub-electron readout noise in a Skipper CCD fabricated on high resistivity silicon

Electrons Take Their Places on a Liquid Helium Grid

An analog VLSI chip for estimating the focus of expansion

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