Abstract: A hiccup-mode short circuit protection circuit and method for a linear voltage regulator using a FET pass transistor uses the capacitance of the pass transistor's gate as a timing element. The regulator's output voltage is monitored, and when it droops below a voltage indicative of a short-circuit condition, the regulator's drive signal is disconnected from the pass transistor. While the short-circuit condition persists, a first current is provided to charge the pass transistor's gate capacitance. When the gate voltage rises above a first predetermined threshold, a second current is provided to further charge the gate capacitance. When the gate voltage rises above a second predetermined threshold, the gate capacitance is discharged. The gate capacitance is cyclically charged and discharged in this way unless the output voltage rises to indicate that the short-circuit condition has cleared, in which case the regulator's drive signal is restored to the pass transistor's gate.

Abstract: Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.

Abstract: Methods and structures are provided that enhance the accuracy of the service attitude of an inclined-orbit spacecraft and, thereby, facilitate reduction of service error between a communication service area and the spacecraft's payload beam. The enhancement is realized by configuring a beacon-receiving antenna to have a beacon-receiving field-of-view that substantially matches a beacon-station window. Preferably, the beacon-receiving field-of-view is elongated and tilted to enhance its match with the beacon-station window in both size and orientation. The goals are also realized by configuring the beacon-receiving antenna to have a beacon-receiving field-of-view that is substantially smaller than the beacon-station window and successively steering a beacon-receiving boresight to successive beacon-receiving attitudes that maintain the beacon station within the beacon-receiving field-of-view over each solar day.

Abstract: Line drivers are provided that are suitable for driving communication cables (e.g., in Data Over Cable Service Interface Specification (DOCSIS) certified systems) without the need for output drivers and their size, power-consumption, noise and signal-distortion penalities. These line drivers directly couple switched current mirrors to a transformer's input winding to simultaneously provide currents in response to a differential input signal and a digital command signal and drive the load impedance to thereby realize a corresponding signal gain.

Abstract: New boron icosahedral ethers and esters formed from Cs2[closo-B12(OH)12],; Cs[closo-1-H-1-CB11(OH)11]; and closo-1,12-H2-1,12-C2B10(OH)10 are disclosed. Also set forth are their preparation by reacting the icosahedral boranes [closo-B12H12]2−, [closo-1-CB11H12]− and closo-1,12-(CH2OH)2-1,12-C2B10H10 with an acid anhdride or acid chloride to form the ester or an alkylating agent to form the ether.

Abstract: The present invention is a circuit comprising two series-coupled field effect transistor (FET) devices with a resistor network coupled in parallel forming a composite device (that can be substituted directly for a single FET device). In applications such as active loads or current sources, the composite device exhibits a greater breakdown voltage and superior high-frequency characteristics. The resistor network provides optimum direct current (DC) bias for depletion mode devices and superior high-frequency loading. Bandwidth and stability are both increased. Furthermore, this circuit is compatible with depletion mode FET processes having a single fixed threshold voltage.

Abstract: A focal plane array has a plurality of detectors for each pixel of the array. The detector having the best operability for each pixel is determined and a custom microlens array is fabricated, with each lens having a focal point directed to the best detector on each pixel. A Multiplexer (MUX) similarly transmits signals from the selected detectors while blocking transmission from the non-selected detectors.

Abstract: This invention describes new LEDs having light extraction structures on or within the LED to increase its efficiency. The new light extraction structures provide surfaces for reflecting, refracting or scattering light into directions that are more favorable for the light to escape into the package. The structures can be arrays of light extraction elements or disperser layers. The light extraction elements can have many different shapes and are placed in many locations to increase the efficiency of the LED over conventional LEDs. The disperser layers provide scattering centers for light and can be placed in many locations as well. The new LEDs with arrays of light extraction elements are fabricated with standard processing techniques making them highly manufacturable at costs similar to standard LEDs. The new LEDs with disperser layers are manufactured using new methods and are also highly manufacturable.

Abstract: Space vector modulation methods and structures are provided that reduce feedback errors which degrade motor control performance. In particular, the rotation of a reference voltage vector Vref is modified as it rotates with respect to voltage vectors that each represent a respective one of converter switch states in an electric-motor control system. One embodiment modifies the reference voltage vector Vref as it approaches various voltage vectors and another modifies the reference voltage vector Vref when its magnitude is less than a predetermined magnitude.

Abstract: A poly fuse trim cell includes a poly fuse and a transistor connected together at a first node; the transistor conducts a current necessary to blow the fuse in response to a control signal. The cell also includes a switching transistor, connected between the first node and a current source circuit. A logic gate is connected to the first node at one input, and to a reset signal at a second input. The output of the logic gate provides the trim cell's output, and controls the switching transistor. When the fuse is intact, the logic gate output is “low” such that the switching transistor is off and the cell's quiescent current is zero. When the fuse is blown, the logic gate output goes “high” upon the occurrence of a reset signal, which turns on the switching transistor and allows the current source circuit to pull down the first node.

Abstract: Mulitplying digital-to-analog converters (MDACs) are provided that reduce signal distortion without significantly raising current demand. These goals are achieved with input structures that lower input impedances and enhance the driving of nonlinear capacitances that are generally presented by the DAC portion of these devices.

Abstract: A high temperature hybrid-circuit structure includes a temperature sensitive device which comprises SiC, AlN and/or AlxGa1−xN(x>0.69) connected by electrodes to an electrically conductive mounting layer that is physically bonded to an AlN die. The die, temperature sensitive device and mounting layer (which can be W, WC or W2C) have temperature coefficients of expansion within 1.06 of each other. The mounting layer can consist entirely of a W, WC or W2C adhesive layer, or an adhesive layer with an overlay metallization having a thermal coefficient of expansion not greater than about 3.5 times that of the adhesive layer. The device can be encapsulated with a reacted borosilicate mixture, with or without an upper die which helps to hold on lead wires and increases structural integrity. Applications include temperature sensors, pressure sensors, chemical sensors, and high temperature and high power electronic circuits.

Abstract: Differential sampler structures are provided that reduce signal distortion and current demand. The structures include first and second buffers that drive first and second capacitors and first and second switches. First and second current pumps are capacitively coupled and also cross coupled to the first and second capacitors relative to the coupling of the first and second buffers to these capacitors. As a result, signal distortion and current demand are both reduced.

Abstract: A bipolar transistor breakdown voltage enhancement circuit extends the voltage swing which can be tolerated at an output terminal driven by an emitter follower-connected bipolar output transistor operating in a high impedance state. The enhancement circuit connects the base of the output transistor to a voltage which extends the allowable high impedance output voltage swing: an NPN output transistor's base is tied to a voltage that is the lower of the output voltage or ground, and a PNP output transistor's base is tied to a voltage which is the higher of the output voltage or VDD.

Abstract: A micro-bore catheter for use with an infusion pump wherein the micro-bore lumen of the catheter acts as an adjustable flow restricting element. The flow rate through the catheter can be increased proportionally by trimming the length of the catheter. One end of the catheter is attached to a needle for insertion of the catheter into the elastomeric septum of a drug infusion pump.

Abstract: Unwanted voltage drops associated with the bit switches of a DAC are compensated with an output amplifier circuit for the DAC that includes a feedback circuit with a switch compensation resistance element that is connected in a combined series/parallel circuit with a feedback resistance circuit, so as to reduce both the size and associated capacitance of the resistance element.

Abstract: A multi layered high impedance structure presents a high impedance to multiple frequency signals, with a different frequency for each layer. Each layer comprises a dielectric substrate, and an array of radiating elements such as parallel conductive strips or conductive patches on the substrate's top surface with a conductive layer on the bottom surface of the bottommost layer. The radiating elements of succeeding layers are vertically aligned with conductive vias extending through the substrates to connect the radiating elements to the ground plane. Each layer presents as a series of parallel resonant L-C circuits to an E field at a particular signal frequency, resulting in a high impedance surface at that frequency. The new structure can be used as the substrate for a microstrip patch antenna to provide an optimal electrical distance between the resonator and backplane at multiple frequencies.

Abstract: In order to generate a carrier frequency Fc, a digital modulator must operate (to satisfy the Nyquist criteria) at a system sample rate Rs which is at least twice the carrier frequency Fc. However, digital modulator structures are provided herein that facilitate the use of M quadrature modulators which modulate, at a reduced modulation rate Rs/M, respective ones of M polyphase cosine elements and M polyphase sine elements with respective ones of interpolated I elements and interpolated Q elements to thereby form M polyphase modulated elements. The modulated elements are then sequentially selected in a multiplexer to form a modulated digital signal. The reduced modulation rate simplifies modulator design and lowers fabrication costs.

Abstract: A method for protecting the surface of a semiconductor material from damage and dopant passivation is described. A barrier layer of dense or reactive material is deposited on the semiconductor material shortly after growth in a growth reactor such as a MOCVD reactor, using the MOCVD source gasses. The barrier layer blocks the diffusion of hydrogen into the material. The reactor can then be cooled in a reactive or non-reactive gas ambience. The semiconductor material can then be removed from the reactor with little or no passivation of the dopant species. The barrier layer can be removed using a variety of etching processes, including wet chemical etching or can be left at the semiconductor material for surface protection. The barrier layer can also be a gettering layer that chemically binds hydrogen trapped in the semiconductor material and/or blocks hydrogen diffusion into the material.

Abstract: A system and method for reducing reaction forces induced in a machine frame by an oscillating tool employs a counterforce assembly which is driven to move along linear slides mounted to the machine frame. The counterforce assembly is driven with a drive signal derived from two signals: a first signal which is proportional to the acceleration of the tool, and a second signal which is directly proportional to the velocity of the oscillating tool. By properly-adjusting the acceleration and velocity components of the drive signal, the magnitude of the reaction forces induced in the machine frame by the oscillating tool can be substantially reduced. The counterforce assembly preferably includes a centering means which prevents it from moving to either end of the slide. An accelerometer is preferably mounted to the machine frame to sense its vibration, with the accelerometer output used to adjust the counterforce assembly's drive electronics to reduce vibration to a minimum.