Patents Represented by Attorney Neil B. Schulte
  • Patent number: 4338590
    Abstract: A multi-stage resistive ladder network which uses extra stages to trim out resistance discrepencies. All of the stages are interconnected in a series. Nominally, current is divided in half within each stage. Half of the current is gated onto a bus in response to logic control signals, and the other half of the current is passed onto the next succeeding stage. Due to various processing limitations, the resistors comprising each stage vary slightly from their nominal value, which in turn upsets the current division. To compensate for this additional current dividing stages are serially connected to the last stage of the ladder. Current from these additional stages are selectively coupled onto the bus in response to the logic signals in addition to the current which is normally coupled thereto.
    Type: Grant
    Filed: January 7, 1980
    Date of Patent: July 6, 1982
    Assignee: National Semiconductor Corporation
    Inventors: Joseph J. Connolly, Jr., James B. Cecil
  • Patent number: 4336489
    Abstract: Butted guard band CMOS circuits have a typical breakdown of about 7 volts. It is often desirable to operate circuitry from supplies greater than 7 volts. For example, 9 volts is a commonly used supply value. An isolated zener diode is fabricated into a CMOS integrated circuit so as to develop a voltage drop equal to guard band breakdown. The zener voltage is coupled by way of a diode-connected transistor to the operating circuitry. The diode drop substracts from the zener voltage so that the circuitry is always operated at a voltage below its breakdown.
    Type: Grant
    Filed: June 30, 1980
    Date of Patent: June 22, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Thomas M. Frederiksen
  • Patent number: 4335371
    Abstract: A single chip integrated circuit analog-to-digital converter uses the successive approximation approach with resistor ladder-switching decoder digital-to-analog coverters coupled to a precision plural input comparator. An on board PROM is provided to store in digital form the information necessary to trim the digital-to-analog converters. The converter is actuated during wafer probing in the manufacturing process and the PROM is programmed with the trim information. Initially, the PROM is bypassed and the digital words needed for accurate trim applied externally. Once the correct trim words are found, the PROM is programmed with the correct words. A 13-bit converter is supplied with ten 7-bit trim words to achieve a fully trimmed product in wafer fabrication.
    Type: Grant
    Filed: April 9, 1979
    Date of Patent: June 15, 1982
    Assignee: National Semiconductor Corporation
    Inventors: Joseph J. Connolly, Jr., Thomas P. Redfern, Thomas M. Frederiksen
  • Patent number: 4335162
    Abstract: A bubble memory includes a garnet film and a pattern of overlying propagation elements, each made of a layer of permalloy and a layer of manganese. The elements define a plurality of paths for propagating magnetic bubble domains under the influence of a Z bias magnetic field and a rotating XY magnetic drive field. The configuration and positioning of the propagation elements is such that the magnetic bubble domains can be selectively routed, e.g. to bypass defective minor loops, by creating barriers over which the magnetic bubble domains will not propagate. Preselected ones of the elements are preferably heated with a laser beam to a temperature which is approximately 75-90% of the melting point of the permalloy. This diffuses the manganese in the permalloy sufficiently to quench the magnetization in the permalloy to thereby create the barriers to bubble propagation.
    Type: Grant
    Filed: April 25, 1980
    Date of Patent: June 15, 1982
    Assignee: National Semiconductor Corporation
    Inventors: James A. Cunningham, Anthony M. Tuxford
  • Patent number: 4331740
    Abstract: A continuous tape is employed in the automatic assembly of semiconductor devices. The tape contains a sequential series of patterns, each one comprising a plurality of metal fingers. Each pattern includes fingers having an inward extension that terminates in a configuration that mates with the contact pattern of the semiconductor device. Desirably these fingers are thermocompression gang bonded to the semiconductor contact pads. This attaches the semiconductor device to the tape for further processing. In one assembly method the fingers have an outward extending portion that is designed for bonding to a secondary structure such as a lead frame destined to become part of the final housing. The fingers in the pattern are joined together by means of a ring located at or near the point at which they are bonded to the lead frame. After the lead frame bonds are achieved, preferably by thermocompression gang bonding, the ring is severed at locations between the fingers.
    Type: Grant
    Filed: April 14, 1980
    Date of Patent: May 25, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Carmen D. Burns
  • Patent number: 4330790
    Abstract: A semiconductor device is bonded to a contact finger pattern which is located in a continuous tape. A metal package cup is fabricated from metal stock so as to have a flat rim portion around its periphery. A plastic insulating sheet is punched so that it forms an overlapping cover for the flat rim and is attached thereto. The tape mounted semiconductor device is then bonded to the inside of the cup and the metal fingers bonded to the insulating sheet covering the flat rim. Provision is made for one of the fingers to connect to the cup. Then the device is encapsulated using one of two techniques. In the first a cap that mates with the cup is provided with a bonded insulating film cover and is bonded to the cup with its overlying metal fingers, so that a metal housing results. An encapsulating material is then injected inside the housing by way of a hole in the cap. Alternatively the semiconductor device can be covered by a suitable casting material.
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: May 18, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Carmen D. Burns
  • Patent number: 4327333
    Abstract: A circuit for supplying a pair of currents that vary in opposite directions as a function of a control current. The pair of currents are coupled to an amplifying stage in which the gain varies in accordance with the relative magnitude of the currents. The circuit includes a differential current source having two output current terminals and a pair of controlled inputs. Both inputs are coupled to individual current sources. One input includes a resistor-diode current sink and the other input includes a current mirror sink. The control current is coupled to the current mirror thus varying the load on the related differential inputs. The current mirror input is also coupled to the diode current sink in the one differential input so that a delay can be introduced into the response to control current. That is, the control current must exceed a predetermined value before the gain reduction action occurs.
    Type: Grant
    Filed: March 17, 1980
    Date of Patent: April 27, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Milton E. Wilcox
  • Patent number: 4326443
    Abstract: An MOS integrated organ circuit compensates an audio frequency signal for variations in amplitude, attack and decay characteristics caused by process variations by adjusting a single variable reference voltage. The circuit intrinsically provides for the tracking of these characteristics, such that the attack and decay characteristics are calibrated by adjusting the variable reference voltage to provide a specified amplitude characteristic.
    Type: Grant
    Filed: May 1, 1980
    Date of Patent: April 27, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Richard W. Bryant
  • Patent number: 4323887
    Abstract: An analog to digital converter is fabricated using CMOS construction and uses a successive approximation register to develop the bits in a digital word. A digital to analog converter converts the digital word to analog voltages which are compared with the analog input. The comparator is coupled to the register so as to determine its word bit sequence. The digital words most significant bit is set first in accordance with whether the analog input is greater or less than half of the reference voltage. Then the next most significant bit is evaluated and this process is continued until the least significant bit is evaluated at which time the conversion is complete. In the CMOS circuit, a switched comparator is employed and it draws a capacitor charging current in its operation. Accordingly, it is useful to buffer the comparator input. Two buffers are employed, one p-type and one n-type. They have common inputs and outputs that are selected as a function of the most significant bit in the digital word.
    Type: Grant
    Filed: October 23, 1980
    Date of Patent: April 6, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Gerald B. Buurma
  • Patent number: 4321691
    Abstract: A magnetic bubble detector stretches a single magnetic bubble domain across two isolated magneto-resistive sensors so that only one of the sensors needs to be functional in order to detect the presence of a magnetic bubble. The magnetic bubble domain can be striped actively by a local field created by a current loop. Alternatively, if the magnetic bubble domain is stretched passively by propagation along a progressively widening pattern of magnetic elements, the pattern can be separated into two isolated patterns, one associated with each sensor, so that only one of the pattern/sensor pairs needs to be functional in order to detect the presence of a magnetic bubble.An active bubble switch can be used as an alternative to the passive stretch array. The bubble switch is coupled to receive the activating current provided to one the sensors for directing magnetic bubble domains to that sensor in response to the application of an activating current to that sensor.
    Type: Grant
    Filed: June 2, 1980
    Date of Patent: March 23, 1982
    Assignee: National Semiconductor Corporation
    Inventor: Robert H. Norton
  • Patent number: 4320521
    Abstract: A data bus transceiver reduces self-induced noise by using trapezoidal drive waveforms. A differential receiver stage of the transceiver has a threshold voltage matched to the midpoint voltage of the drive waveform to reduce distortion, and a low-pass filter matched to the slew rate of the drive waveform to reduce noise while causing minimum progation delay. The transceiver has been integrated using back-to-back junction capacitors in the driver and filter circuits and these capacitors have been biased to reduce their variation in capacitance as a function of the voltage applied across them.
    Type: Grant
    Filed: July 25, 1980
    Date of Patent: March 16, 1982
    Assignee: National Semiconductor Corporation
    Inventors: Ramanatha V. Balakrishnan, William R. Fowler
  • Patent number: 4307682
    Abstract: A watering cup especially useful for watering chickens having a first contact actuated valve for admitting water which first valve bears against a second interior valve and holds the second valve open. The first valve can be removed for cleaning and inspection without the necessity of shutting down the water pressure since removal of the first valve closes the second valve and prevents leakage.
    Type: Grant
    Filed: October 17, 1980
    Date of Patent: December 29, 1981
    Assignee: Miller Little Giant Co., Inc.
    Inventor: Donald R. Bollman
  • Patent number: 4296681
    Abstract: A hydraulic servomechanism permitting a wrist like universal motion of an extending member through a generally hemispherical operating range in which a sphere or sphere-like drive member is mounted for movement in a spherical or sphere-like cavity and driven by fluid pressure in intersecting circumferential channels mounted either in the drive member or the support means. The circumferential channels are sealed by curved metal bands with gaskets along the edge. Hydraulic fluid enters the channels through ports in the sealing bands themselves so as to facilitate easier movement of the drive member.
    Type: Grant
    Filed: November 14, 1979
    Date of Patent: October 27, 1981
    Inventor: Mark E. Rosheim
  • Patent number: 4266486
    Abstract: A door linkage for a side dump railroad car operable to automatically lower the door on the low side of the car when the car body is tilted to dump its contents thereof.
    Type: Grant
    Filed: August 30, 1979
    Date of Patent: May 12, 1981
    Assignee: The Maxson Corporation
    Inventor: Douglas A. Puariea
  • Patent number: 4263852
    Abstract: A side shiftable railway car in which the bolsters resting on the wheeled trucks engage a movable center plate on the underside of the car. The center plate may be slid sideways along retaining flanges welded to the underside of the car and locked in place by heavy keeper pins adapted to be inserted and extracted manually with levers.
    Type: Grant
    Filed: February 1, 1979
    Date of Patent: April 28, 1981
    Assignee: The Maxson Corporation
    Inventor: Philip J. Kramlinger
  • Patent number: 4264410
    Abstract: A metal abrading material formed from acid etching with a resist pattern comprising a plurality of polygonal shapes with accentuated corners dispersed in a pattern chosen to intermix cutting points with planing edges.
    Type: Grant
    Filed: January 22, 1980
    Date of Patent: April 28, 1981
    Assignee: Minnesota Micro Metal, Inc.
    Inventor: John J. Frantzen
  • Patent number: 4254598
    Abstract: A corrugated panel adapted to be nailed to a roof between the base roof structure and the roof covering material so as to provide a multitude of ventilating air passages under the roof covering and thermally isolate the roof covering from the building.
    Type: Grant
    Filed: May 21, 1979
    Date of Patent: March 10, 1981
    Inventor: Roger R. Rugroden
  • Patent number: 4240806
    Abstract: A metal abrading material formed from acid etching with a resist pattern comprising a plurality of polygonal shapes with accentuated corners dispersed in a pattern chosen to intermix cutting points with planing edges.
    Type: Grant
    Filed: August 16, 1978
    Date of Patent: December 23, 1980
    Assignee: Minnesota Micro Metal, Inc.
    Inventor: John J. Frantzen
  • Patent number: 4240355
    Abstract: A side dump rail car tilted by means of hydraulic cylinders at each end of the car which are centrally located. The edge of the car is retained by an engagement lug slid into place hydraulically to determine direction of tilt.
    Type: Grant
    Filed: May 21, 1979
    Date of Patent: December 23, 1980
    Assignee: The Maxson Corporation
    Inventor: Douglas A. Puariea
  • Patent number: 4236357
    Abstract: An etched metal abrasive formed from a laminated sheet of steel having a top layer of high carbon steel and a base layer of low carbon steel.
    Type: Grant
    Filed: May 8, 1979
    Date of Patent: December 2, 1980
    Assignee: Minnesota Micro Metal, Inc.
    Inventor: John J. Frantzen