Hewlett-packard Company

Exabyte Corporation

Sifera, Inc.

Christopher Koerner

Alberto Gutierrez, Jr

Masaharu Goto

James Oliver Barnes

Thomas K Bohley

Grosvenor H Garnett

Charles E Moore

James Zweighaft

Stephen James Sheafor

Bradford C Lincoln

James R Hulings

Robert Sugar

Edward G Pumphrey

Mark H Moyer

Jonathan L Huie

A crossbar routing arrangement is disclosed for use in a digital system having three or more buses. An associated method is also disclosed. The routing arrangement is configured for transferring a set of data received from any particular one of the buses to any other selected one of the buses and includes a control arrangement associated with each bus for dividing the set of data into at least first and second subsets of data and for adding self-routing signals to each data subset which signals identify the selected bus. A switching arrangement is configured for directing the first and second data subsets in a predetermined way responsive to the self-routing signals. The control arrangement cooperates with the switching arrangement to transfer the data subsets over physically distinct data transfer paths defined between the switching arrangement and the control arrangements. In accordance with one feature, the configuration of the routing arrangement provides for linear expansion whereby to service buses having increased width and/or to service an increased number of buses in a cost effective manner while, in either instance, maintaining high data throughput.

Linearly expandable self-routing crossbar switch

A system and method is provided for controlling a brushless DC motor (100), the motor being of the type having a plurality of coils (25, 26, 27) and a switching amplifier coil driving circuit (25A, 26A, 27A) including a plurality of transistors (21, 22, 29, 30, 33, 34). Current application to the plurality of transistors is controlled to obtain, near a commutation point of the motor, a simultaneous rise in current applied to a first of the transistors and a fall in current applied to a second of the transistors. Controlling application of current to the plurality of transistors involves, for each of the transistors, generating a PWM gate drive signal by selectively switching between a nominal PWM signal and a constant signal. The selective switching is in response to a synthesized state signal, the synthesized state signal being generated to alternate variably between the two states in accordance with a desired ramping of current to the first and second transistors. In one embodiment, the control system is employed for a motor used to rotate a reel of a helical scan tape drive.

Digital acoustic noise reduction in electric motors driven by switching

A system and method for compensating in real time the dynamic power variation of a computer chip containing CMOS devices is provided. The present invention functions to control the temperature variations on the chip thus eliminating the drift to analog signals associated with CMOS devices. The present invention controls the temperature with the use of a compensation heater located on the CMOS chip. The compensation heater is driven by a plurality of signals which act in harmony with one another to control the temperature on the chip when it becomes unstable. The system and method includes driving the compensation heater with a maximum dynamic power value to effectively maintain the temperature on the chip, evaluating the chip for temperature fluctuation, and compensating for the temperature fluctuation by driving the compensation heater with at least one compensation power value.

System and method for dynamic power compensation

A delay element for fine tuning the position in time of timing edges of an input signal, comprising a first and a second inventer, each comprising a data input, a control input and a data output. The delay element further comprises a node comprised of a connection between the data output of the first inverter and the data input of the second inverter. An adjustable control voltage is included for applying a biasing voltage to the first and second control inputs to thereby control the amount of charge supplied to the node. Finally, the variable capacitance means is connected to the node for applying finite amounts of capacitance to the node to delay and thereby fine tune in time the timing edges of the input signal propagating from the first inverter to the second inverter.

Programmable capacitance delay element having inverters controlled by

The present invention is directed to a delay line for providing fine timing adjustment on subsequent edges of an input signal. The delay line comprises a plurality of delay elements for fine tuning the position in time of the timing edges of the input signal. Each delay element has a data input and data output where the data output is connected to the subsequent delay element's data input, thereby forming a delay line with delay elements connected in series. This implementation facilitates the addition of fine increments of delay to be added to the input signal and thereby enable fine tuning of timing edges. Also, included is a wired-OR multiplexor having data inputs connected to the data outputs of the plurality of the delay elements and a control input to select a particular data output to thereby provide an output signal having delayed timing edges.

Fine/coarse wired-or tapped delay line

A system for generating an analog regulating voltage to be supplied to one or more circuit elements on an integrated circuit. The circuit elements have operational characteristics that are voltage dependent and the analog regulating voltage having the a property of changing with temperature, power supply voltage, and manufacturing process variations so as to substantially eliminate the effects of such variations on the operational characteristics of the circuit elements.

System for generating an analog regulating voltage

The present invention is a time vernier providing fine timing control of an input signal having coarse timing edges. The time vernier comprises a receiving means for receiving a value representing a desired time delay to be added to the coarse timing edge input. The desired time delay may have both fine and coarse delay aspects. The time vernier also comprises a first decoding means for decoding the fine delay aspect and generating fine delay control signals, as well as a second decoding means for decoding a coarse delay aspect and generating coarse delay control signals. A delay line is also included in the time vernier which has inputs to receive the input signal having coarse timing edges, the fine and coarse delay control signals, and a control voltage which automatically adjusts with temperature and power supply variations, so as to provide for temperature and power supply compensation. The delay line combines the fine and coarse delay signals to provide an output signal with fine timing edges. Furthermore, the architecture of the present invention enables an automated method of calibration in order to adjust fine and coarse delay elements for fabrication process variations and photolithography variations.

CMOS pseudo-NMOS programmable capacitance time vernier and method of

A plural channel indirect digital to analog converter. Words containing address bits and data bits are received on an input and entered into a specific one of the converter channels under control of the address bits of the word. The data bits are applied to a binary rate multiplier of the channel which generates a pulse modulated output signal representing the binary value of the received data bits. The pulse modulated output signal is applied to an associated filter which converts the pulse modulated signal to an analog output signal whose amplitude represents the binary value of the received data bits. Gating circuitry ensures that each output pulse is of a precisely controlled pulse width. One of the converter channels is used to calibrate the output level of the filters. The number of data bits applied to the different channels may need not be the same and may vary in number from a minimum of 1 to a maximum of m.

Indirect D/A converter

Pulse modulation circuitry which receives n binary data bits and generates a rate/width pulse modulated signal representing the binary value of the received data bits. The lower order m of the n bits generate a rate modulated signal having a number of pulses equal to the binary value of the m bits. The remainder of the n bits width modulate the rate modulated pulses. Each least significant bit increase in the binary value of the received date bits increases the width of a rate modulated pulse by a predetermined amount.

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Longmont, CO, United States of America

Christopher Koerner