Bull Hn Information Systems, Inc.

Other

Honeywell Bull, Inc.

George A Person

In order to prevent a logic circuit including a multi-stage temporary storage array having both valid and invalid state combinations from locking up in an inadvertently entered invalid state and from alternating between invalid state combinations, support logic circuitry is employed which is configured to force the array back to a valid state combination. The forcing operation may be alternatively undertaken immediately or in synchronism with the next succeeding clock pulse following entry into the invalid state combination. A specific valid state combination to be entered following entry into a specific invalid state may be predetermined.

Sensing and responding to invalid states in logic circuitry

In order to determine if a micropackage containing a plurality of integrated circuits, at least some of which are supplied with a reference voltage, should be classified as 'risky' the reference voltage current is measured for each micropackage in a group of logically identical micropackages. The measurements are arranged for statistical analysis, and an initial threshold is selected above which a micropackage is classified as 'risky'. The subsequent history in operation of measured micropackages, as well as reference voltage measurements on additional newly fabricated like micropackages, is entered into the database to permit refining the position of the threshold. In one variant, all micropackages in an initially measured group are 'passed'.

Detecting presence of N+ diffusion faults in a micropackage containing a

Spurious cavity resonance effects in a cabinet housing electronics circuitry are suppressed by determining the maximum repetition rate or frequency for legitimate signals which can appear in the circuitry and then establishing the dimensions of each cavity within the cabinet such that each cavity's resonant frequency is higher than the critical repetition rate/frequency. Since a given cavity in a cabinet is typically block-shaped (such as the space between a cabinet door and the circuit panel facing the door), a special purpose formula may be employed to obtain a good approximation of the cavity's resonant frequency, and the cavity dimensions then adjusted to raise the cavity resonant frequency above the critical frequency. For the still more particular cavity configuration in which the length is greater than the width which is much greater than the depth, a further simplified formula can be employed to find an approximate cavity resonant frequency. In addition, for the common configuration in which one or more significant intrusions reduce the cavity volume, a more complex formula may be employed to find its approximate resonant frequency with the cavity dimensions then being adjusted to raise that approximate resonant frequency above the critical frequency. The method may be employed either in the design stage or at a remedial stage.

Method for limiting spurious resonant cavity effects in electronic

A method and exemplary apparatus are disclosed for increasing the heat transfer capabilities between a nominally planar, but actually slightly concave, first surface (such as the substrate of a micropackage) and a planar second surface such as a heat sink. This result is obtained by filling any non-contacting space intermediate the heat transfer surfaces of the thermal interface with helium. In a test environment for a micropackage, the heat transferring surfaces are, respectively, a substrate outer face of the micropackage and a planar surface of a test fixture heatsink. Helium is introduced, under pressure, through one or more apertures provided in the heatsink planar surface to displace air and occupy any non-contacting space between the heat transferring surface which result from the presence of non-planar regions of the substrate outer face, particularly those resulting from quasi-spherical surface distortion. Such quasi-spherical surface distortion is often observed in micropackages and is typically in the form of a generally slightly concave surface configuration caused by stresses applied to the inner face of the substrate by the overlaying circuit laminations. In one embodiment of the invention, the helium is supplied at sufficient pressure to ensure a constant leak of helium to the ambient at the periphery of the thermal interface ot further promote temperature uniformity by convection as well as by the superior heat transfer characteristics of helium over air.

Substrate thermal interface employing helium gap

Instability resulting from the presence of reactive components in the output filter of regulated power supplies of the general type in which regulation is obtained by feeding back the output voltage to the regulator circuitry is eliminated by deriving a feedback signal from the output voltage which includes not only a direct component, but also separately derived first and second derivative components referenced to the reactive characteristics of a series output choke and parallel output capacitor of the output filter circuit. The amplitude ratios of the feedback signal components are selected in accordance with a key aspect of the invention to eliminate the output filter from the characteristic equation of the power supply to thereby eliminate instability whatever its source.

Cancellation of regulator output filter poles by second derivative

Instability resulting from the presence of reactive components in the output filter of regulated power supplies of the general type in which regulation is obtained by feeding back the output voltage to the regulator circuitry is eliminated by deriving a feedback signal from the output voltage which includes not only a direct component, but also separately derived first and second derivative components referenced to the reactive characteristics of a series output choke and parallel output capacitor of the output filter circuit. The amplitude ratios of the feedback signal components and the elements of the local feedback loop of the regulator error amplifier are selected in accordance with key aspects of the invention to eliminate the output filter (including the effective series resistance of the output filter capacitor) from the characteristic equation of the power supply to thereby eliminate instability whatever its source.

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Phoenix, AZ, United States of America

George A Person