Bell Telephone Laboratories

Carlo Heinrich Sequin

Michael F Tompsett

Robert H Krambeck

Edward J Zimany, Jr

Ronald E Crochiere

Robert Henry Walden

Peter Van Wilde

A charge transfer device includes two channels and a common input structure. The input structure is operated in a manner to divide a charge packet of signal-independent size into two complementary packets for movement along the two channels. A single-channel embodiment employs a similar input structure.

Linear differential charge splitting input for charge coupled devices

The source-drain resistance of an MOS load transistor (M.sub.2) is linearized by means of a pair of properly designed auxiliary MOS transistors (M.sub.3 and M.sub.4) whose source-drain paths are electrically coupled (conductively or through an amplifier) with the load transistor (M.sub.2). The gate electrode of the load transistor (M.sub.2) is connected to the common node point (N.sub.34) between the auxiliary transistors (M.sub.3 and M.sub.4); whereas the transconductances (.beta..sub.3 and .beta..sub.4) of the auxiliary transistors (M.sub.3 and M.sub.4) are designed such that during operation the resulting feedback signal from the common node point (N.sub.34) to the gate electrode of the load transistor (M.sub.2) reduces its nonlinearity.

Linear load MOS transistor circuit

A sensing circuit is disclosed for detecting and amplifying the output signal of a semiconductor charge transfer device, particularly of the transversal filter type containing sensing split-electrodes for sensing the charge packets being transferred through the device. The circuit includes two amplifier means, one of which suppresses the (useless) common mode signal and the other of which detects the (useful) difference signal of the split-electrodes. In addition, the sensing circuit is provided both with 'reset' switching means for eliminating spurious signals due to stray charges that accumulate on the sensing electrodes and with 'clamping' switching means for eliminating noise of the kTC type generated by the 'reset' switching.

Sensing circuit for semiconductor charge transfer devices

An on-chip semiconductor pre-filter device is designed with a prescribed low frequency passband (0 to f) and a prescribed stopband (F.+-.f), with a frequency roll-off therebetween. The pre-filter performs a weighted averaging of signal samples taken from an input electrical signal at a suitable sampling frequency and converts the weighted average into an equivalent charge packet for input by injection into a semiconductor charge coupled device (CCD) driven on the same chip by a clock of frequency F. In this way, the 'reflected' parts (in band: F.+-.f) of the frequency spectrum of the CCD are suppressed from the input to the CCD, thereby suppressing undesired aliasing in the CCD.

Anti-aliasing pre-filter circuit for semiconductor charge transfer device

Charge transfer devices which permit movement of charge carriers in two noncollinear directions in the surface plane of the device. A network of electrodes in two levels of metallization is combined with an appropriate doping of the storage medium to define the charge transfer paths. The direction of charge transfer is determined by an appropriate pulsing of the network which may take the form of different driving sequences of a number of phases in various embodiments. This concept may be used for both charge coupled and bucket brigade devices.

Two-dimensional transfer in charge transfer device

In order to reduce the steady dark current background effect on the output sequence of charge packets in a semiconductor charge transfer device, each charge packet on its first arrival at the output end of a transfer path is inverted with respect to a suitable reference level; and the inverted charge packet is then recirculated through the same transfer path for subsequent detection on its next arrival at the output end of the path.

Semiconductor charge transfer devices with dark current background

Charge transfer devices of either the charge coupled or bucket brigade type are described which allow movement of charge carriers in two noncollinear directions in the surface plane of the device. One level of metallization is utilized to provide the appropriate surface potential for charge transfer in the storage medium. The electrode pattern comprises charge transfer electrodes which are coupled diagonally to one of a plurality of conduction paths. Directionally is aided by asymmetric potentials under each electrode which may be formed by localized regions of fixed charge at the surface of the storage medium. Horizontal or vertical transfer is determined by the sequence of biasing the conductive paths. In one embodiment, the electrode pattern is formed by strips of conductive material shaped in the form of diagonally overlapping quadrilateral members and positioned so as to form an array resembling the normal two-dimensional array of discrete transfer electrodes.

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New Providence, NJ, United States of America

Carlo Heinrich Sequin