Patents Assigned to STMicroelectronics
  • Patent number: 5973959
    Abstract: A reading circuit comprises a current mirror circuit connected, at a first and a second output node, to the drain terminals of an array cell and of a reference cell; a comparator whose inputs are connected to the output nodes of the current mirror circuit; a ramp generator having an enabling input connected to the output of the comparator and an output connected to the control terminal of the reference cell. Biasing the gate terminal of the array cell to a constant voltage, when the currents flowing in the array cell and in the reference cell are equal, the value assumed by the ramp voltage is proportional to the threshold value of the array cell; at that time the comparator is triggered and discontinues the ramp increase, supplying as output the desired threshold value.
    Type: Grant
    Filed: July 22, 1998
    Date of Patent: October 26, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Danilo Gerna, Roberto Canegallo, Ernestina Chioffi, Marco Pasotti, Pier Luigi Rolandi
  • Patent number: 5969491
    Abstract: The sensing of the rotor position for synchronizing the drive of a multi-phase brushless motor when driven in a "multi-polar" mode is carried out by interrupting the driving current in at least one of the windings of the motor coupled with a zero-cross sensing circuit of the BEMF signal. This done by using a first logic signal, enabling a logic gate for asserting a zero-cross event detected by the circuit by a third logic signal, and simultaneously resetting the first signal and the third signal after a certain period of time from the instant of interruption.
    Type: Grant
    Filed: July 14, 1998
    Date of Patent: October 19, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Marco Viti, Michele Boscolo, Alberto Salina
  • Patent number: 5969541
    Abstract: A tri-state I/O buffer and a method of inhibiting current to an I/O buffer arranged to be powered by a supply voltage and to drive an output terminal are provided. The I/O buffer preferably has an output driving circuit connected to the supply voltage for driving the output terminal and includes a first plurality of transistors defining an isolated floating well circuit for operatively connecting the output terminal to the supply voltage and a second plurality of transistors defining a pull-down circuit for operatively connecting the output terminal to ground. An input control circuit is connected to the output driving circuit and the supply voltage, and is arranged to receive a buffer input signal for controlling the buffer input signal to the output driving circuit.
    Type: Grant
    Filed: May 19, 1997
    Date of Patent: October 19, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Charles D. Waggoner
  • Patent number: 5969977
    Abstract: An electronic memory device organized into sections which are in turn divided into blocks formed of cells and their associated decoding and addressing circuits, the cells being connected in a predetermined circuit configuration and each block being included between two opposite contact regions which are interconnected by parallel continuous conduction lines referred to as the bit lines. In the present invention, at least one interruption is provided in each bit line near a contact region by inserting a controlled switch which functions as a block selector. Advantageously, the proposed solution allows each block to be isolated individually by enabling or disabling as appropriate the switches of the cascade connected blocks.
    Type: Grant
    Filed: December 29, 1997
    Date of Patent: October 19, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Emilio Camerlenghi, Paolo Cappelletti, Luca Pividori
  • Patent number: 5966110
    Abstract: An LED driver drives a plurality of light emitting diodes (LEDs) having first terminals connected to a common output stage and second terminals respectively receiving different, suitably rectified, phases of a sinusoidal signal. An output stage of the LED driver includes a first bipolar transistor coupled between a first supply terminal and the first terminals of the LED's. A first MOS transistor drives the base of the first bipolar transistor. The gate of the first MOS transistor is coupled to a first reference voltage. A second bipolar cascode transistor is connected in series with the first MOS transistor and biased by a second reference voltage such that the voltage across the first MOS transistor does not exceed a limit value.
    Type: Grant
    Filed: November 26, 1996
    Date of Patent: October 12, 1999
    Assignee: STMicroelectronics S.A.
    Inventor: Klaas Van Zalinge
  • Patent number: 5966034
    Abstract: In a pulse filtering device, the pulse signal is sampled to enable the counting of this signal by an asynchronous counter. A pulse of calibrated duration is generated when the counting reaches a predetermined number.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: October 12, 1999
    Assignee: STMicroelectronics S.A.
    Inventor: Jean-Francois Leon
  • Patent number: 5963025
    Abstract: A voltage regulator (400) having a charge pump includes a bias current circuit (402) which produces a bias current (I.sub.bias). The bias current (I.sub.bias) is mirrored by a first mirror circuit (404) and multiplied by gain stage Q4.sub.beta and mirrored again by a factor "c" on the output of DMOS2. The same I.sub.bias is mirrored by a ratio "b" and multiplied by the product of Q5.sub.beta and Q6.sub.beta. The push-pull current operation at the output terminal (416) is obtained by turning on and off switches SW1 (418) and SW2 (420) that are controlled by a clock signal. The voltage regulator (400) further includes an output voltage clamp (424) that keeps control of the V.sub.boost voltage by controlling the amount of bias current (I.sub.bias).
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: October 5, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Gianluca Colli
  • Patent number: 5963485
    Abstract: A bit line recovery circuit for random access memory. The circuit includes a pair of pull-up devices, each of which is connected to a bit line of a bit line pair. Pass gates are disposed between a sense amplifier and the bit lines. The pull-up devices are cross-coupled such that the gate node of the pull-up devices are connected to the sense amplifier on the opposed side of the pass gates in order to rapidly turn on the appropriate pull-up device following a memory cell read operation.
    Type: Grant
    Filed: August 19, 1998
    Date of Patent: October 5, 1999
    Assignee: STMicroelectronics, Inc.
    Inventors: James Brady, James L. Worley
  • Patent number: 5963386
    Abstract: A disk resident system for managing split data sector information in a headerless format magnetic disk device. The split data sector information is stored in a split data sector information field that is recorded in available areas within a headerless disk format such as the gaps within the headerless disk format or in available space within disk administration fields. Preferred areas within a headerless disk format include the gap immediate preceding a servo burst, the gap immediately following a servo burst, or within the servo burst itself, so that the split data sector information is readily available at the time the servo burst is read and interpreted.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: October 5, 1999
    Assignee: STMicroelectronics N.V.
    Inventor: Nicolas C. Assouad
  • Patent number: 5963443
    Abstract: A power terminal is connected to a DC power source. A differential amplifier has primary and secondary input terminals and an output terminal, and a device applies a reference voltage to the secondary input terminal of the differential amplifier. A phase inverter has an input terminal connected to the output terminal of the differential amplifier and has primary and secondary output terminals that output two output signals of opposite phase. A push-pull drive circuit has primary and secondary input terminals connected to the primary and secondary output terminals of the phase inverter, and has primary and secondary output terminals connected to a switching element that alternately turns on and off by being driven by the two output signals of opposite phase that are provided from the output terminals of the phase inverter.
    Type: Grant
    Filed: April 28, 1998
    Date of Patent: October 5, 1999
    Assignee: STMicroelectronics K.K.
    Inventor: Masaaki Mihara
  • Patent number: 5959332
    Abstract: The device has an SCR structure in a P surface zone of a silicon die. A P+ anode region for connection to an I/O terminal to be protected is formed in an N region, as well as an N+ contact region; an N+ cathode region is formed in another N region for connection to the earth of the integrated circuit. The striking potential of the SCR, that is, the intervention potential of the protection device, is determined by the reverse breakdown of the junction between the first N region and the P-body surface zone. This potential is influenced by an electrode which is disposed over the junction and is connected to the cathode constituting the gate of a cut-off N-channel MOS transistor. The concentrations are selected in a manner such that the P-channel MOS transistor defined by the P region, by the portion of the first region over which the electrode is disposed, and by the P-body, has a conduction threshold greater than the striking potential.
    Type: Grant
    Filed: August 3, 1995
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, S.r.l.
    Inventors: Enrico Ravanelli, Lucia Zullino
  • Patent number: 5960311
    Abstract: A method of forming a thick interlevel dielectric layer containing sealed voids, formed in a controlled manner, over a substantially planar surface in semiconductor device structure, and the semiconductor structure formed according to such a method. The sealed voids are used to reduce interlevel capacitance. A plurality of metal signal lines are formed over a globally planarized insulator. A thick layer of first conformal interlevel dielectric is deposited over the metal signal lines and over the intermetal spacings formed between the metal signal lines. Because of the thickness, flow properties, and manner of deposition of the interlevel dielectric and the aspect ratio the intermetal spacings, voids are formed in the first conformal interlevel dielectric, in the intermetal spacings. This interlevel dielectric is then etched or polished back to the desired thickness, which exposes the voids in the wider intermetal spacings, but does not expose voids in the narrower intermetal spacings.
    Type: Grant
    Filed: August 14, 1997
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, Inc.
    Inventors: Abha R. Singh, Artur P. Balasinski, Ming M. Li
  • Patent number: 5960277
    Abstract: A merged power device structure, of the emitter-switching type, in which the emitter of the bipolar power transistor has a minimum-width pattern which is aligned to the trenches of a trench control transistor. Thus the current density of the bipolar is maximized, since the emitter edge length per unit area is increased. The parasitic base resistance of the bipolar can also be reduced.
    Type: Grant
    Filed: June 4, 1997
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Richard A. Blanchard
  • Patent number: 5960464
    Abstract: A method and apparatus employing a memory management system that can be used with applications requiring a large contiguous block of memory, such as video decompression techniques (e.g., MPEG 2 decoding). The system operates with a computer and the computer's operating system to request and employ approximately 500 4-kilobyte pages in two or more noncontiguous blocks of the main memory to construct a contiguous 2-megabyte block of memory. The system can employ, on a single chip, a direct memory access engine, a microcontroller, a small block of optional memory, and a video decoder circuit. The microcontroller retains the blocks of multiple pages of the main memory, and the page descriptors of these blocks, so as to lock down these blocks of memory and prohibit the operating system or other applications from using them. The microcontroller requests the page descriptors for each of the blocks, and programs a lookup table or memory mapping system in the on-chip memory to form a contiguous block of memory.
    Type: Grant
    Filed: August 23, 1996
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Christopher S. Lam
  • Patent number: 5959910
    Abstract: A test mode of a memory device may be invoked that varies the sense amplifier clocking of the memory device as a function of manipulation of a control signal external to the memory device. At the appropriate logic state of a test mode enable signal, the test mode of the memory device is entered. Normal clocking of the sense amplifier is suspended during the test mode and the sense amplifier is clocked according to the transition of an external control signal from a first logic state to a second logic state. A predetermined period of time after the transition of the external control signal, the sense amplifier if clocked.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: David Charles McClure
  • Patent number: 5959465
    Abstract: A method is provided for operating a programmable logic array in an integrated circuit. Each stage of the circuit is enabled only during the time necessary for that stage to propagate an incoming signal. Enable signals are generated for the stages of the circuit, using a dummy circuit which replicates elements of the circuit in dimension, orientation and connectivity. These elements provide a delay path, such that an input signal applied coincidentally to the programmable logic array circuit and the dummy circuit produces outputs of the dummy circuit which define times for applying and removing the enable signals from stages of the programmable logic array circuit.
    Type: Grant
    Filed: December 29, 1995
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics Ltd.
    Inventor: Robert Beat
  • Patent number: 5959902
    Abstract: In a first operation mode the level shifter transmits as output a logic input signal and in a second operation mode it shifts the high logic level of the input signal from a low to a high voltage. The level shifter comprises a CMOS switch and a pull-up transistor; the CMOS switch comprises an NMOS transistor and a PMOS transistor which are connected in parallel between the input and the output of the shifter and have respective control terminals connected to a first supply line at low voltage and, respectively, to a control line connected to ground in the first operation mode and to the high voltage in the second operation mode; the pull-up transistor is connected between the output of the shifter and a second supply line switchable between the low voltage and the high voltage and has a control terminal connected to the first supply line.
    Type: Grant
    Filed: February 25, 1998
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Marco Fontana, Antonio Barcella
  • Patent number: 5956239
    Abstract: The turn-on delay of a current mode switching converter is reduced by an error summing block including a window comparator to the input of which is fed the output voltage of the converter before being filtered by the low pass filter and to which a low threshold and high threshold reference voltages are applied, both of which are referred to the reference voltage of the converter. The error summing block also includes a differentiating circuit whose input is coupled to the so defined "under" output of the window comparator and outputting a pulse of a preestablished duration at the incoming of a rising front of the input signal. Two amplifiers of the same gain K, are also provided, and both are enableable for outputting an amplified signal only when enabled. In addition, two summing circuits are also included.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: September 21, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventor: Davide Giacomini
  • Patent number: 5955873
    Abstract: A band-gap reference voltage generator comprises an operational amplifier comprising a first input and a second input, the first input being coupled to a first feedback network and the second input being coupled to a second feedback network both coupled to an output of the operational amplifier providing a reference voltage. The first feedback network contains an emitter-base junction of first bipolar junction transistor and the second feedback network contains an emitter-base junction of second bipolar junction transistor. A selectively activated current supply supplies a bias current to the operational amplifier, the current supply being deactivatable in a substantially zero power consumption operating condition for turning the reference voltage generator off. A start-up circuit activated upon start-up of the reference voltage generator for a fixed, prescribed time interval forces a start-up current to flow through the first bipolar junction transistor means.
    Type: Grant
    Filed: October 30, 1997
    Date of Patent: September 21, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Marco Maccarrone, Matteo Zammattio, Stefano Commodaro
  • Patent number: RE36319
    Abstract: According to the present invention, a structure for holding broken select lines in a memory array deselected addresses the prior art problems associated with floating broken select lines, such as standby current and disruption of attached memory cells. The structure is a high impedance device which is placed on the end of select lines so that if a select line is broken during fabrication, the high impedance device, will hold the broken end of the select line to the desired deselect voltage. Select lines which have a driver at one end only and are broken during fabrication, but have the high impedance device on the other end, are not allowed to float. The high impedance device is also suitable for select lines which are not broken and previously were anchored at just one end. Suitable high impedance devices include a reverse biased diode, a weak transistor, a poly R memory cell load device, and an ON or OFF TFT memory cell load device.
    Type: Grant
    Filed: November 7, 1997
    Date of Patent: September 28, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: William C. Slemmer