Patents Represented by Attorney H. C. Chan
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Patent number: 6507220Abstract: A typical occurrence in communication circuits, such as transmitters and receivers, is the internal transfer of a sequence of pulses, known as a clock signal, from an amplifier to a digital circuit. For proper operation, it is critical that the digital circuit accurately comprehends the clock signal. However, in some communications circuits a phenomenon called duty-cycle distortion—that is, a distortion of the apparent duration of the pulses in clock signals—causes the digital circuit to read the clock signals as having a longer or shorter duration than intended. Accordingly, the inventors devised unique circuitry for correcting or preventing this distortion. One exemplary circuit uses a voltage divider, comprising a pair of transistors, to set the DC or average voltage of the clock signals input to the digital circuit at a level approximating the logic threshold voltage of the digital circuit.Type: GrantFiled: September 28, 2001Date of Patent: January 14, 2003Assignee: Xilinx, Inc.Inventors: Eric Douglas Groen, Charles Walter Boecker
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Patent number: 6505337Abstract: A method for implementing a large multiplexer with FPGA lookup tables. Logic that defines a multiplexer is detected and implemented according to the number of inputs and the target FPGA architecture. In one situation, a large multiplexer is implemented in two stages. The first stage implements wide AND functions of each of the input signals using lookup tables and carry logic. In a second stage, the resulting decoded input signals are combined in a wide OR gate again formed from lookup tables and a carry chain. In another situation, the multiplexer is implemented as a tree structure using lookup tables that implement 2:1 multiplexers in combination with other 2:1 multiplexers provided by configurable logic blocks of the FPGA.Type: GrantFiled: December 19, 2000Date of Patent: January 7, 2003Assignee: Xilinx, Inc.Inventors: Ralph D. Wittig, Sundararajarao Mohan
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Patent number: 6504415Abstract: In many electronic systems, it is common to communicate data from a transmitter in one device to a receiver in another. Accurate communications requires use of several matched clock signals. Mismatches in these clock signals cause transmitters to add “jitter” to transmitted data or receivers to be more intolerant of jitter in received signals, increasing the chances of mis-interpreting the data. Accordingly, the inventors devised an exemplary clock-distribution method which entails generating a base set of matched clock signals, deriving at least two separate sets of matched clock signals from the base set, and distributing one of the sets of clock signals to a set of matched components in a circuit and the other set of matched clock signals to a different set of components in the same circuit. The clock signals driving the matched components are isolated from mismatched aspects of the other components, and thus exhibit better matching.Type: GrantFiled: August 28, 2001Date of Patent: January 7, 2003Assignee: Xilinx, Inc.Inventors: Moises E. Robinson, Ahmed Younis
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Patent number: 6501396Abstract: A scalable physical coding sublayer (PCS) can be adjusted to provide different combinations of communication channels and data widths. The PCS can use 8B/10B encoders having a disparity input connection and at least one disparity output connection. In one embodiment, the encoder has both a synchronous and an asynchronous disparity output connection. The encoder can be coupled with additional encoders to provide an expanded width channel of 16B/20B encoding. Additional configurations are possible. In expanded operation, only one of the encoders needs to output special codes. The encoders, therefore, include a slave input connection to place the encoder in a slave mode so that a special code is replaced with an inert special code. All but one encoder in an expanded system are slave encoders. An idle input connection is also provided in the encoders to place the encoder in an idle mode where pre-defined data is output from the encoder.Type: GrantFiled: March 30, 2001Date of Patent: December 31, 2002Assignee: Xilinx, Inc.Inventors: Joseph Neil Kryzak, Thomas E. Rock
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Patent number: 6501297Abstract: The resource cost associated with each resource in a programmable logic device (PLD) can be obtained from topology information. In one embodiment, the PLD can be geometrically divided into an array of logical tiles. The cost can be set equal to the number of tiles the resource intersects (span). A signal path between a.source and a destination can be routed using this resource cost. In another embodiment, the cost is set as the maximum value between the vertical and horizontal spans (instead of the total span). This embodiment often increases the speed of routing.Type: GrantFiled: September 5, 2001Date of Patent: December 31, 2002Assignee: Xilinx, Inc.Inventor: Raymond Kong
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Patent number: 6489837Abstract: A system for controlling the impedances of circuits on an integrated circuit chip is provided. At least one circuit is selected to operate as a p-channel reference circuit, and at least one circuit is selected to operate as an n-channel reference circuit. Other circuits are selected to operate as circuits and/or line termination circuits. A digitally controlled impedance (DCI) circuit controls the p-channel reference circuit to determine a desired configuration of p-channel transistors for use in the circuits. The DCI circuit further controls the n-channel reference circuit to determine a desired configuration of n-channel transistors for use in the circuits. The DCI circuit takes into account such factors as resistances of p-channel transistors in the p-channel reference circuit, resistances of n-channel transistors in the n-channel reference circuit, as well as temperature, voltage and process variations.Type: GrantFiled: November 30, 2001Date of Patent: December 3, 2002Assignee: Xilinx, Inc.Inventors: David P. Schultz, Suresh M. Menon, Eunice Y. D. Hao, Jason R. Bergendahl, Jian Tan
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Patent number: 6480999Abstract: The present invention provides a new method to handle power and ground signals in modular design of programmable logic devices. During module implementation, the power and ground signals of each module are associated with area constraint properties. When performing routing in the module implementation phase, the power and ground signals together with regular local signals of the module are routed in accordance with their respective area constraint properties. However, the area constraint properties of the power and ground signals are removed during assembly phase while the area constraint properties of the local signals are retained.Type: GrantFiled: July 26, 2001Date of Patent: November 12, 2002Assignee: Xilinx, Inc.Inventors: Raymond Kong, Sandor S. Kalman
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Patent number: 6466055Abstract: An integrated circuit input buffer system includes numerous buffers used to receive input signals. The buffer system controls the buffers in a manner that places some of the buffers in a standby mode while other buffers are active. The integrated circuit input buffer system reduces the capacitive load on any individual buffer. The buffers can be activated in a variety of patters, such as sequential activation. In one embodiment, the buffers have differential transistors coupled to receive differential input signals. The differential transistors are coupled to conduct a total current defined by a tail current circuit. The buffers are placed in a standby state by electrically isolating the tail current from the differential transistors. In one embodiment, a standby transistor is electrically located between the differential transistors and a tail current transistor. The differential transistors conduct a trickle current during the standby state.Type: GrantFiled: June 15, 2001Date of Patent: October 15, 2002Assignee: Xilinx, Inc.Inventor: Michael Joseph Gaboury
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Patent number: 6437599Abstract: An integrated circuit output driver has been described. The driver can operate in a mode selected from a group of possible modes. The described driver can operate in either a positive emitter coupled logic (PECL), a current mode logic (CML), a grounded low voltage differential signal (GLVDS), or a low voltage differential signal (LVDS) mode. The driver circuit includes a output driver, an emphasis circuit and termination circuitry. A driver bias circuit controls the bias currents for the output driver and the emphasis circuit. The driver bias circuit is controlled to select the desire driver mode. A termination circuitry can be activated based upon the selected mode.Type: GrantFiled: November 6, 2000Date of Patent: August 20, 2002Assignee: Xilinx, Inc.Inventor: Eric Groen
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Patent number: 6173391Abstract: A bossless computer program architecture in which each program module is hierarchically equal is used to develop complicated software applications. Each program module is associated with a parameter file. The characteristics and operation of the program modules are determined by their associated parameter files. These modules communicate by writing statements to the parameter files associated with other modules. Once written, the origin of these statements is ignored. Thus, there is no need to “return” to the modules which originate the statements. Further, the statements are executed by the modules without regard to their origins. This new architecture does not require the preservation of linkage information because there is no need for the program modules to return information or control to other modules. Various applications of this architecture to windows-based environment and multimedia applications are disclosed.Type: GrantFiled: February 18, 1998Date of Patent: January 9, 2001Assignee: Sofmap Future Design Co., Ltd.Inventors: Daisuke Tabuchi, Wataru Shoji, Ichiro Nakajima
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Patent number: 6081404Abstract: When an auto-reverse is designated in the state of the magnetic tape of a cassette being transferred in a first direction with a planetary gear meshing with a first reel gear, a motor reverses, and also a central gear reverses such that the planetary gear starts revolving around the central gear away from the first reel gear. The planetary gear meshes with a mode changing gear, and rotate the mode changing gear, a projection and a switching member. In accordance with the rotation of the switching member, a head base moves horizontally and a magnetic head separates from the magnetic tape. Further, a bent piece on the head base abuts against a stopper, due to which the revolution of the planetary gear stops, and the planetary gear stays to assuredly transmit the revolution of the central gear to the mode changing gear. Moreover, the projection while in rotation presses a slider. As the slider slides, the magnetic head turns 180.degree..Type: GrantFiled: March 23, 1998Date of Patent: June 27, 2000Assignee: Asahi CorporationInventor: Susumu Arai
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Patent number: 6062942Abstract: A rotation control unit is disposed on an intersection portion. The rotation control unit has a plurality of blocks and extends into a running way of an automotive toy. As an automotive toy enters an intersection from a running way, the automotive toy pushes a block to rotate a rotation control unit. Due to this rotation, the block is moved away from the running way and the automotive toy on the running way is made movable. A block is placed on the other running way to close it so that the other automotive toy is prevented from entering the intersection portion. While the automotive toy is passing the intersection, the rotation control unit retains this state. After the automotive toy has passed the intersection portion, the pressure applied to the block is removed and the rotation control unit is returned to its original position, whereby the automotive toy can enter the intersection portion from the other running way.Type: GrantFiled: May 26, 1998Date of Patent: May 16, 2000Assignee: Asahi CorporationInventor: Nobuaki Ogihara
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Patent number: 6031527Abstract: An application can be formed by using a plurality of program modules each having an associated display window. These modules could communicate with each other to perform desired activities. A user organizes the windows associated with these modules in a desired spatial arrangement. Various parent-child relationships among the display windows are used to place constraints on the appearance of the windows. When the program modules are executed, they communicate with each other to perform desired activities while the associated windows maintain a predetermined graphic relationship. Consequently, the application gives the appearance that it contains tightly coupled program modules instead of modules that can be selected and arranged easily by a user with little programming experience.Type: GrantFiled: July 12, 1996Date of Patent: February 29, 2000Assignee: Sofmap Future Design, Inc.Inventors: Wataru Shoji, Daisuke Tabuchi, Ichiro Nakajima
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Patent number: 6011549Abstract: Text image on a monitor can be scrolled pixel-by-pixel instead of line-by-line or character-by-character. An application window (for showing images generated by an application) and a child window are generated. The text image is drawn on the child window instead of on the application window. The size of the application window is smaller than the child window. Only the portion of the child window overlapping the application window is displayed by a computer screen. If a user desires scrolling, the child window is moved, a pixel at a time, in a direction corresponding to the direction of scrolling. When a full line or a full character is scrolled, the child window clears itself and returns to its original position. At the same time, the text image is scrolled one line or one character on the child window so as to match the pixel-based scrolling. As a result, the user sees a smooth scrolling of a text image.Type: GrantFiled: August 3, 1998Date of Patent: January 4, 2000Assignee: Sofmap Future Design, Inc.Inventors: Wataru Shoji, Daisuke Tabuchi, Ichiro Nakajima
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Patent number: 5974469Abstract: A specialized communication controller class is used to manage communications in an object oriented programming system. Classes in the system are not designed to communicate directly with each other, and communication between classes is routed by this controller class. As a result, there is no need for each class to keep track of any hierarchical relationship of classes in an application in order to be able to communicate with other classes. Members of the object oriented programming system contain parameter files and can send commands to the controller class. The controller class executes the commands without return result to the senders. Similarly, the controller class can send commands to other class members, and these commands are executed without returning result to the controller class.Type: GrantFiled: July 12, 1996Date of Patent: October 26, 1999Assignee: Sofmap Future Design, Inc.Inventors: Wataru Shoji, Daisuke Tabuchi, Ichiro Nakajima
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Patent number: 5929465Abstract: A light emitting diode of compound semiconductor having a triangular-shaped top surface is disclosed. It is found that these dies have higher light output, better chip handleability, increased material usage and reduced slicing damages, when compared to prior art slicing geometry. Examples of suitable compound semiconductors are GaP, GaAsP, AlGaAs, etc., in the III-IV material group or ZnSe in the II-IV material group. In the preferred embodiment, the dies are sliced into equilaterial triangles.Type: GrantFiled: August 25, 1997Date of Patent: July 27, 1999Assignee: Highligh Optoelectronics, Inc.Inventors: Coeyen Nee, Chen-ho Wu, Jeff Chang, C. James Hwang
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Patent number: 5903890Abstract: A database system can be formed by combining a plurality of single-association databases each associated with a database driver. A single-association database contains a plurality of records, and each record associates one piece of data with another piece of data. Each database driver contains a parameter file and is designed to perform searches on its associated database. Each database driver also contains means for sending a command to the parameter file of another database driver. The recipient database driver executes the command without returning result of execution to the sending database driver. The database system also contains a software module for interacting with the database drivers to achieve a desired search result.Type: GrantFiled: May 15, 1998Date of Patent: May 11, 1999Assignee: Sofmap Future Design, Inc.Inventors: Wataru Shoji, Daisuke Tabuchi, Ichiro Nakajima
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Patent number: 5885893Abstract: A stress-free and non-impact method of creating interconnects between electronic devices and electrodes is disclosed. A first conductive paste is deposited on one electrode. An electronic device, such as a dice, is attached to the electrode using the conductive paste. A second conductive paste is applied to the top surface of the dice and a third conductive paste is applied to another electrode. A conductive wire is deposited to the second and the third conductive paste. After curing, the two electrodes are connected to the dice. There is no impact required in creating the interconnect.Type: GrantFiled: June 9, 1997Date of Patent: March 23, 1999Assignee: Highlight Optoelectronics, Inc.Inventors: Coeyen Nee, Jeff Chang, C. James Hwang, Tze-Ping Chen
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Patent number: 5877761Abstract: Text image on a monitor can be scrolled pixel-by-pixel instead of line-by-line or character-by-character. An application window (for showing images generated by an application) and a child window are generated. The text image is drawn on the child window instead of on the application window. The size of the application window is smaller than the child window. Only the portion of the child window overlapping the application window is displayed by a computer screen. If a user desires scrolling, the child window is moved, a pixel at a time, in a direction corresponding to the direction of scrolling. When a full line or a full character is scrolled, the child window clears itself and returns to its original position. At the same time, the text image is scrolled one line or one character on the child window so as to match the pixel-based scrolling. As a result, the user sees a smooth scrolling of a text image.Type: GrantFiled: July 12, 1996Date of Patent: March 2, 1999Assignee: Sofmap Future Design, Inc.Inventors: Wataru Shoji, Daisuke Tabuchi, Ichiro Nakajima
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Patent number: 5859904Abstract: A method for connecting a local and a remote device using a plurality of telephone lines is disclosed. The remote device calls the local device on one of the telephone lines to establish a first telephone connection. The local device sends the other telephone numbers to the remote device on the first telephone connection. The remote device can then establish additional telephone connections. Once connections are established, the two devices can divide a data stream into smaller components. These components are sent via these telephone connections. These components are received by the receiving devices and combined to recover the original data stream. One of the application of the present invention is videophone.Type: GrantFiled: January 3, 1997Date of Patent: January 12, 1999Assignee: Advis, Inc.Inventor: Tapeng Huang