Abstract:
A frequency test circuit (200) includes a built-in self test (BIST) circuit (212) which provides for testing of a frequency generating circuit such as an oscillator circuit (100). The test circuit (200) includes circuit stages (202-208) which help produce a reference signal (210) which has substantially the same frequency as that produced by the oscillator circuit (100) when it is operational. Since the low current oscillator circuit (100) can fail at any one of the divider or level shifting stages (106-112), the test circuit (200) can determine if the reference signal and the output signal of the oscillator have substantially the same frequency and produce a test condition signal indicative of either a pass or failed test at test port (214).
Abstract:
A method and apparatus, for applying a current to a coil of a write head assembly of a disk drive, or the like, to cause the flux within the coil to rapidly reverse, has an H-bridge having two pair of two switchable transistors. Each pair of the transistors is connected between a supply voltage and a reference potential, and is adapted to be connected to the coil between the two transistors of each pair. The two transistors of the first pair may be connected to receive a control signal to turn on complementary transistors of the first and second pair of transistors to selectively control current flow in the coil in first or second directions. A reference current source supplies a reference current, and one of the transistors in each of the first and second pairs of transistors is connected when turned on to mirror the reference current to control the currents in the coil. First and second parallel transistors are connected in parallel respectively with the mirror transistors, the first and second parallel transistors being connected to be turned on respectively by the control signal and the inverted control signal concurrently with the respective mirror transistor. A pair of timing elements turn off respective ones of the parallel transistors after a predetermined time so that when the parallel transistors are turned on, the current in the coil overshoots a value established by the mirror transistors.
Abstract:
A VDMOS structure with an added n- doping component, and a LOCOS oxide self-aligned to it, at tie surface extension of the drain. The additional shallow n- component permits the body diffusion to be heavier, and hence reduces the risk of latchup.
Abstract:
A circuit and method are provided for generating an initializing signal to a master enable fuse circuit on a redundant line decoder. An initialization pulse may be applied to a master enable circuit having a master enable fuse. The master enable fuse may be coupled to a switched voltage supply powered selectively by battery voltage and external Vcc. A circuit for generating the INITIAL signal determines the transition from a power down state to a powered state. A series of delay elements in a generating circuit generates a predetermined initialization pulse of around 3 ns to 5 ns. Half-latch circuits may be initialized between a first and second voltage threshold. Accordingly, the master enable circuits may be set to the proper initialization states for proper operation and minimum power consumption.
Abstract:
A circuit for controlling isolation transmission gates connected to the bit lines of a dynamic random access memory (DRAM) device. The circuit includes tri-state circuits which selectively configure transmission gate impedance. The transmission gates are configured for low impedance when stored data is provided to the bit lines. The transmission gates are configured for intermediate impedance when the bit lines are driven towards reference voltage levels. Further, the transmission gates are configured for high impedance to isolate the sense amplifiers from blocks of memory cells that are not involved in the execution of an access to a row of memory cells.
Abstract:
An integrated circuit package for direct mounting of an integrated circuit die to a printed circuit board is disclosed. The integrated circuit die includes a silicon sensor that detects changes in external variables, such as providing an image of a human fingerprint. The integrated circuit die has wire bond pads formed along only one side thereof to provide maximum exposure of the top surface area of the silicon sensor. The die is affixed to the printed circuit board and an adhesive surface coating, such as epoxy, is applied to the die and the printed circuit board for sealing the die thereto. The adhesive surface coating is formed from a first bead applied to the printed circuit board to cover at least the ends of the wires bonded to the board and a second bead applied to the first bead and the die to enclose the sides of the die and partially overlap the wire band pads and wires on top surface thereof.
Abstract:
A method of reducing the memory required for decompression of a compressed frame by storing frames in a compressed format using DCT compression and decoders for implementing such a method are disclosed. The decoder is coupled to a memory where the frame can be stored. The decoder includes a decoder module having a parser, a block decoder module and a motion compensation engine. The decoder module is coupled to a DCT encoder module, which has an output coupled to the memory. The decoder also includes a stored DCT decoder module, which has an input coupled to the memory, a first output coupled to the motion compensation module and a second output that functions as an output of the decoder. In operation, any prediction frames needed for motion compensation decompression of the compressed frame are decompressed in the stored DCT decoder module. The compressed frame is decompressed in the decoder module to obtain a decompressed frame. The decompressed frame is compressed in the DCT encoder module to obtain a recompressed frame. The recompressed frame is then stored in memory. In a DCT based decoder, this is only performed for frames having interpicture prediction errors, such as P and B frames. Frames that do not have interpicture prediction errors, such as I frames can by-pass most of the decoder module, and all of the DCT encoder module. The compressed frame can be stored in the memory without having been decompressed and recompressed.
Abstract:
A planar, capacitive-type, rectangular, and multi-pixel fingerprint sensing array is mounted on the horizontal and generally rectangular top-surface of a dome that extends upward generally from the center of a horizontally disposed and generally rectangular silicon substrate member. The dome is formed by four upward extending and inclined, or tapered, side wall surfaces, at least one wall surface of which carries electrical circuit paths that electrically connected to the various circuit elements of the sensing array. A generally rectangular, encircling and wall-like card carrier assembly includes a generally horizontal upper-surface having a generally centered opening through which only the dome and sensing array project upward. The bottom-surface of the card carrier assembly is mounted to edge portions of the silicon substrate member in a manner to surround and protect all but the upward extending dome. A flexible membrane or laminate is sealed to the top-surface of the card carrier assembly to form a flexible surface over the sensing array. The card carrier assembly includes a circuit path having an external portion and having an internal portion that connects to the wall-mounted internal electrical circuit paths, the external portion providing external connection to the internal sensing array.
Abstract:
A semiconductor device structure and method are presented for increasing a breakdown voltage of a junction between a substrate of first conductivity type and a device region. The structure includes a region of second conductivity type in the substrate completely buried in the substrate below and separated from the device region. The region of second conductivity type is located a predetermined distance away from the device region. The distance is sufficient to permit a depletion region to form between the region of second conductivity type and the device region, when a first voltage is applied between the device region and the substrate. The distance also is determined to produce a radius of curvature of the depletion region, when a second voltage that is larger than the first voltage is applied between the device region and the substrate, that is larger than a radius of curvature of the depletion region about the device region that would be formed if the region of second conductivity type were not present. Traditional field shaping regions spaced from the device region at a surface of the substrate and spaced from the region of second conductivity type may be used in conjunction with the buried ring, if desired.
Abstract:
A layout is provided for an SRAM structure. The layout includes a first storage transistor cross-coupled to a second storage transistor to form an SRAM cell. The source regions of the first and second storage transistors are formed in a common region in the substrate to provide a more compact and dense array. The memory cell also includes a first access transistor and a second access transistor appropriately coupled to the appropriate data storage notes. The gate electrodes for the storage transistors and the access transistors are substantially parallel to each other thus providing advantages in operational characteristics and layout efficiencies. The channel regions are also exactly perpendicular to the gate electrodes and are parallel to each other for each of their respective transistors, thereby obtaining similar benefits. The memory cell is designed having a low aspect ratio, preferably lower than 1.2. A single metal line has two contacts to the common source region to ensure grounding of the memory cell at all times and the removal of any stray and parasitic currents which may occur from time to time. The same metal source line is also connected to the P well to ensure that the source region and P well are held at the same voltage at all times and to prevent P well bounce.