Showing papers on "Decoupling (electronics) published in 1995"

Performance of the decoupled ACRI-1 architecture: the perfect club

Abstract: This paper examines the performance potential of decoupled computer architectures on real-world codes, and includes the first performance bounds calculations to be published for the highly-decoupled ACRI-1 computer architecture. It also constitutes the first published work to report on the effectiveness of a decoupling Fortran90 compiler. Decoupling is an architectural optimisation which offers very high sustained performance through large-scale latency hiding. This paper investigates the applicability of access and control decoupling to real-world codes. We illustrate this with compiler-generated decoupling optimisations for the Perfect Club benchmark suite on the Advanced Computer Research Institute's ACRI-1 system, utilising the frequency of loss of decoupling (LOD) events as a measure of the effectiveness of decoupling to each code. We derive bounds for the performance of these codes and show that, whilst some exhibit performance roughly equivalent to that on vector computers, others exhibit considerably higher performance potential in a decoupled system.

Power bus decoupling on multilayer printed circuit boards

Abstract: Guidelines for the selection and placement of decoupling capacitors that work well for one-sided or two-sided printed circuit boards are not appropriate for multilayer boards with power and ground planes. Boards without internal planes take advantage of the power bus inductance to help decouple components at the higher frequencies. An effective decoupling strategy for multilayer boards must account for the low inductance and relatively high capacitance of the power bus. >

State variable decoupling and power flow control in PWM current source rectifiers

Abstract: Current source PWM rectifiers among others are gradually replacing thyristor line commutated rectifiers as a source of variable DC power. Advantages include reduced line current harmonic distortion and complete power factor control, including unity power factor operation. However, due to intrinsic nonlinearities and stability problems, the control of the rectifier has usually been achieved using off-line patterns or direct line current control in the abc frame. This paper proposes a state variable control technique that introduces more flexibility in the control of the rectifier and a more straightforward approach to controller design. The proposed technique consists in linearizing the state variable model of the system in the dq frame, decoupling and independently controlling the two components of the line current (active and reactive), eliminating the input damping resistors, and rejecting the effect of supply voltage variations. Also, a space vector modulation technique is used to maximize the current gain and switch utilization of the rectifier. The paper includes a complete formulation of the equations of the decoupled system and a controller design procedure. Experimental results on a 2 kVA DSP based prototype confirm the theoretical considerations.

A decoupling control method of reluctance type bearingless motors considering magnetic saturation

Abstract: The interference of the torque component current of a motor with the radial position control of reluctance-type bearingless motors is investigated. In order to cancel this interference, a decoupling control method has been proposed. With this method, machine parameter identification of radial force production is very important. It is shown that the radial force constants exhibit significant variations in accordance with the torque component current due to magnetic saturation. The parameter tuning of the decoupling compensator taking into account the magnetic saturation is found to realize very stable operation in radial rotor position control.

Addressing noise decoupling in mixed-signal IC's: power distribution design and cell customization

Abstract: An important and largely unexplored aspect of power distribution synthesis is cell customization. Through automatic cell customization, power I/O cell assignments and local substrate and power supply decoupling may be tailored to reduce deleterious noise effects on analog circuits in mixed-signal environments. Techniques for simultaneous power grid design (topology and sizing) and cell configuration/customization are described that allow designers to handle more difficult chip-level noise problems. Synthesis results on an industrial mixed-signal example demonstrate the effectiveness of this approach. >

On-chip decoupling capacitor optimization for high-performance VLSI design

Abstract: This paper describes the on-chip power bus modeling and switching noise analysis for high performance circuit design, and the methodology to optimize the placement of on-chip decoupling capacitors The switching noise is analyzed at both the package level and the chip level An equivalent circuit which consists of time-varying resistors, loading capacitors, and decoupling capacitors, is used to simulate the switching activities of functional blocks Both the resistive and inductive voltage drops on the power bus are modelled to identify the hot spots on the chip and /spl Delta/V across the chip Based on the noise analysis results, a decoupling capacitor insertion algorithm is proposed to determine the amount of decoupling capacitance needed to keep the power supply voltage within specification, and optimize the final size and location of on-chip decoupling capacitors

Printed radiating element with two highly decoupled input ports.

Abstract: The authors present a very efficient technique based on the symmetry of the feeds to strongly reduce the port-to-port coupling of dual-polarisation printed antennas. This technique was applied to a dot-coupled microstrip stacked structure fed by stripline, a breadboard was made, and a decoupling of -35 dB or better was achieved over a large bandwidth.

An experimental investigation of 4-layer printed circuit board decoupling

Abstract: This paper examines the measured power bus impedance of fully populated 4-layer printed circuit boards with internal power and ground planes. Three boards provided by two leading computer companies were evaluated. Each of the state-of-the-art high-speed boards used in this study employed surface-mount decoupling capacitors to reduce noise on the power bus. The boards were measured with and without some or all of their decoupling capacitance. The effectiveness of the decoupling capacitors as a function of location and frequency and the relationship between board impedance and power bus noise was explored. The behavior of 4-layer boards is shown to be quite different than that of boards without planes or boards with closely spaced planes.

On-chip decoupling capacitor design to reduce switching-noise-induced instability in CMOS/SOI VLSI

Abstract: The supply noise from the packaging of CMOS/SOI circuits can cause performance degradation, reliability reduction and even loss of circuit functionality due to the device latch-up problem. By properly adding on-chip decoupling capacitors in the proximity of the circuitry, we can effectively alleviate the switching noise problem and improve the performance of CMOS/SOI circuits.

Surface coil elements

Abstract: A coil element, comprising a quadrature surface coil, includes side by side loops, slightly overlapped to the degree necessary to cancel mutual inductance. A coil includes a split-capacitor configuration for balanced-to-unbalanced conversion between the coil and a coaxial cable, without interfering with the highly magnetic environment of a magnetic resonance imaging system. A coil includes multiple diodes and current stabilizing impedances in parallel, or alternatively a combination of a fast low-power PIN diode and a slow high-power diode to effectively multiply the power handling capability of fast diodes for passive decoupling in a decoupling circuit for reducing the risk to the patient over active decoupling. A coil includes a counter-rotating decoupling circuit to cancel the effects of decoupler radiation, and to prevent lowering of the quality factor of the decoupling circuit and the detection of undesirable image artifacts. A coil includes a capacitor and decoupling circuit opposite that of the primary tuning and decoupling circuit for increased symmetry during the imaging cycle receive and transmit phases.

Scan based testing for analog module within a mixed analog and digital circuit

Abstract: An integrated circuit containing analogue operation circuitry having a plurality of nodes for input and output of signals during normal operation, a plurality of scan cells connected to at least said plurality of nodes for containing signals to be utilized in selected tests to be performed on said analogue operation circuitry and responsive to selected output signals is provided. A method for testing a module of analogue circuitry incorporated into an integrated circuit having other circuitry by decoupling a plurality of module signal terminals from respective normal operation connections to a plurality of scan cells, and inputting at least portions of test suites and sensing test result output signals through at least selected ones of said scan cells is provided.

MCM substrate with high capacitance

Abstract: It is well established that thin film capacitors have good electrical characteristics; for that reason they are often used in high frequency applications. We have investigated planarization of bottom capacitive electrodes which must make direct contact with a co-fired ceramic surface, and adjustment and control of the Thermal Coefficient of Expansion (TCE) difference between high dielectric constant material and the base MCM ceramic substrate. Combining thin film capacitors with MCM substrates can result in high frequency decoupling capacitors (with 100/spl times/ the capacitance of comparable co-fired thin layer alumina constructions), space savings, and significant improvement in performance over conventional discrete chip capacitors. >

Scan based testing for analogue circuitry

Abstract: An integrated circuit containing analogue operation circuitry having a plurality of nodes for input and output of signals during normal operation, a plurality of scan cells connected to at least said plurality of nodes for containing signals to be utilized in selected tests to be performed on said analogue operation circuitry and responsive to selected output signals is provided. A method for testing a module of analogue circuitry incorporated into an integrated circuit having other circuitry by decoupling a plurality of module signal terminals from respective normal operation connections to a plurality of scan cells, and inputting at least portions of test suites and sensing test result output signals through at least selected ones of said scan cells is provided.

High-performance decoupling control techniques for various rotating field machines

Abstract: This paper presents a comparative study of different field-oriented rotating-field machines, including squirrel cage induction machines, series-connected wound rotor induction machines, and synchronous machines. Evaluation of various field-oriented rotating-field machines for high-performance applications is presented. The concept of torque linearization and decoupling control is studied and compared for the various field-oriented motors. Computer simulations, experimental results and space phasor diagrams are employed to illustrate the dynamics of decoupling control for the various field-oriented-control (FOC) systems. The control complexity and parameter sensitivity of various FOC drive motors are compared. >

Integrated chip multilayer decoupling capacitors

Abstract: A multilayer decoupling capacitor structure is disclosed, having a first decoupling capacitor with one electrode formed in a conductively doped silicon substrate and a second electrode made of conductively doped polysilicon. A third bifurcated conductive layer disposed above the second electrode in conjunction with a fourth conductive layer above the third layer form a second and third decoupling capacitor. The first decoupling capacitor serves to decouple circuitry associated with dynamic random access memory cells, while the second and third decoupling capacitors provide decoupling for further circuitry.

Effects of on-package decoupling capacitors on the simultaneous switching noise

Abstract: Effects of on-package decoupling capacitors on the simultaneous switching noise (SSN) of output drivers are presented. The effectiveness of the capacitor is a function of inductance from switching drivers to capacitors, and the signal/VSS/VDD stack-up of the package. For a /spl mu/-strip structure, the decoupling capacitor provides an AC shunt path between VSS and VDD that minimizes the impedance for signal transmission that leads to the reduction of SSN. The reduction of SSN is dependent on the inductance from chip pad to decoupling capacitor. Increasing this inductance will render the capacitor ineffective. For a tri-layer stripline structure, the decoupling capacitor has little effect on SSN reduction. SSN simulation results are compared and are consistent with the measurement data of an SSN dynamic electric test chip.

Field oriented control of induction motors using neural networks decouplers

Abstract: This paper presents a novel approach to field oriented control (FOC) of induction motor drives. It discusses the introduction of artificial neural networks (ANN) in the area of decoupling control of induction motors using field oriented control principles. Two ANNs are presented for direct and indirect FOC applications. The first performs estimation of the stator flux and the second is trained to realize the decoupling control of the motor. The two ANNs use the backpropagation learning process to update their weights. A decoupling controller and a flux estimator are realized upon these ANNs using the MATLAB/SIMULINK Neural Network Toolbox. The data for training are obtained from a computer simulation of the system and from experimental measurements. The methodology used to train the network is presented and the results show very interesting features and good potential as an alternative to the conventional field oriented decoupling control of induction motors.

Nonlinear decoupling of an induction motor drive with input filter

Abstract: In this paper, the nonlinear decoupling control of a high power induction motor with input filter is investigated. Keeping a field-oriented control structure, the decoupling terms are modified so that the physical characteristics of the plant can be taken into consideration. Finally, in order to separate the problems of input filter instability and induction motor control, a decoupled supply voltage control is presented.

Position-transmitting electromagnetic quanta and particle radiation detector

Abstract: A method and apparatus for image signal decoupling in position-transmitting high-vacuum electromagnetic radiation quanta or particle detectors. The electromagnetic radiation quanta or particles impinge on a spatially resolving anode structure through a photoelectron converter layer (in the case of electromagnetic radiation) and directly through an electron multiplier as an electron avalanche (in the case of particle radiation). The electron avalanche is first collected for a short time inside the vacuum on the anode side by means of a high-resistance, conducting semiconductor thin film, and is then read out capacitively from the outside through the glass bottom (counter-substrate) of the detector device as an image charge by means of a low-resistance anode layer of suitable structure. The capacitive decoupling permits high spatial resolution when the internal resistances of the charge collecting layer and the readout anode layer are optimally adapted to one another. The decoupling requires only a simple high-resistance monolayer in the vacuum with a single voltage contact. The spatially resolving anode structure outside the vacuum can be modified or exchanged to individually adapt the spatial resolution.

Hybrid HVAC systems

Abstract: This article identifies the needs for decoupling the HVAC functions under certain conditions by using an hybrid system, which can be optimised with the Merit of Hybrid System (MOH) Diagram

Robust decoupling for active car steering holds for arbitrary dynamic tire characteristics

Abstract: A robust decoupling control law was derived for active car steering under some mild assumptions. The control law simpliies the steering transfer function from the steering wheel input commanded by the driver to the lateral acceleration at the front axle. In this paper it will be shown that the decoupling is preserved even if nonlinear diierential equations are assumed as a tire model.

Task decoupling in robot manipulators

Abstract: Task decoupling in robotic manipulators implies that there is a subset of joints primarily responsible for the completion of a subset of the manipulator task. In this paper, we take a novel and general view of task decoupling in which we identify link subsystems primarily responsible for completion of a subset of the manipulator task components, which is not necessarily position or orientation. Our analysis leads to the discovery of other decoupled manipulator geometries never identified before, wherein the decoupled system is responsible for a subset of degress-of-freedom involving a hybrid combination of both position and orientation. Closed-form inverse kinematic solutions for these manipulator geometries are therefore guaranteed. Task decoupling also implied singularity decoupling wherein singularities of decoupled subsystems are equivalent to the manipulator singularities. The analysis leads to a novel and efficient method for identifying the singularities and solving the inverse kinematics problem of six-axes manipulators with decoupled geometries. The practicality of the concepts introduced is demonstrated through an industrial robot example involving a hybrid position and orientation decoupling.

Time and frequency domain analysis of integral decoupling capacitors

Abstract: Decoupling capacitors have been designed and included in high-speed packaging systems to avoid voltage drops across the power supply caused by interconnect inductance. They are also used to reduce simultaneous switching noise between the power supply and device I/O buffers. This paper will review three different measurement methods by which these capacitors were analyzed. It will discuss the possible detriments when making both low frequency and high frequency measurements on electronic packages and surface mount chip components using commercial instruments and fixtures. Two different types of high performance electronic packages with integral decoupling capacitors were analyzed. The models derived from the measurements were included in a circuit simulation to determine the effectiveness of decoupling noise between the device drivers and the system power supply. The results will provide insight into the effectiveness or these types of capacitors used within a high-speed electronic system.

Decoupling control of robot manipulators by using variable-structure disturbance observer

Abstract: Disturbance observers have been used extensively for decoupling control of robot manipulators. But the conventional disturbance observers are sometimes useless for decoupling control because they are usually constructed under the assumption that the disturbance is constant during the sampling period and the trade-off between decay rate of the estimation error and the sensitivity to sensor noise is an inevitable problem. This paper proposes a variable-structure disturbance observer and a method for decoupling control of robot manipulators by applying the proposed observer. The proposed observer can treat a general class of disturbances and overcome the problems of the conventional disturbance observers, that is, sensitiveness to sensor noise and delay of convergence. The proposed control method is implemented into an experimental 3-degree-of-freedom DD robot. It is shown through experimental results that the proposed method can realize decoupling control for robot manipulators more precisely and robustly.

Light valve for video,graphics and data display

Abstract: The light valve has the control of the light transparency for each pixel provided by optical coupling and decoupling of a light transparent apparatus. The coupling and decoupling apparatus is driven by electronic signals and the light is modulated. For decoupling the light valve lets light through. A total reflection occurs at the face of the pixel element which stands against air. Two substrate layers (3,6) with two seals contain a liquid (4). The refractive indices of the liquid and substrate layers are the same.