Abstract:
A capacitor mounting structure for printed circuit boards wherein the capacitor includes first and second terminals which are connected to first and second conductor planes in the printed circuit board. Three vias are mounted in the printed circuit board in a position to be aligned with the middle of the capacitor. A first conductor pad is mounted underneath one end of the capacitor and includes spaced apart extension portions which electrically attach to the first and third via. A second conductor pad is mounted under the other end of the capacitor and includes a central extension portion which attaches to the second or middle via. In this manner, the region available for generation of parasitic inductance is minimized thereby increasing the operating efficiency of the capacitor.
Abstract:
A computer system with a digitizer based screen display in which the digitizer data is buffered through a first-in first-out memory (FIFO). The processor is only interrupted when a full digitizer data packet is available in the FIFO, rather than being interrupted on each data byte available in the FIFO. The FIFO can hold multiple digitizer data packets, so that data is not lost should the processor in the computer system be unable to immediately handle these digitizer data packets. The system also provides a filter in a separate controller that examines each digitizer data packet to determine if the pen is in a predefined screen location that performs a prespecified function. If so, rather than pass the digitizer data packet to the system processor through the FIFO, the command is passed through a separate register to the processor based on the "hotspot" touched on the screen.
Abstract:
A power converter including a complementary regeneration circuit for eliminating oscillations and conserving leakage energy to increase the efficiency of a flyback power converter. The complementary regeneration circuit includes a regeneration capacitor, a regeneration switch, a diode and appropriate timing circuitry to switch the regeneration capacitor in and out of the circuit at the appropriate times. Due to the operation of the regeneration switch, the capacitance of the regeneration capacitor is much larger than a typical snubber/clamp capacitor, so that it overdamps the circuit eliminating voltage overshoot typically appearing across the primary switch. The regeneration capacitor charges with regeneration energy and drives negative current into the primary inductor, holding the voltage across the primary switch constant when the secondary current goes to zero. When the regeneration switch is turned off, the negative current in the primary inductor drains the capacitance in the primary switch, which activates the inherent diode of the primary switch causing low voltage across the primary switch when it is turned on. A simple resistor or transistor circuit may be added between the input voltage and the PWM timing circuit to change the frequency of operation to compensate the regeneration energy for changes in the input voltage. Similarly, a resistive element coupled between the PWM timing circuit and an auxiliary voltage having a voltage proportional to the output voltage changes the operating frequency to compensate the regeneration energy for changes in the output voltage.
Abstract:
A system for monitoring performance of an intelligent array expansion system includes a controller for communicating with a host computer and associated intelligent array expansion systems, each of which has a plurality of fixed disk drives. The controller incorporates firmware to monitor a plurality of predetermined performance data, such data being thereafter stored in information storage devices. At the same time counts are maintained for selected parameters which are of interest to a systems manager. Such counts and the performance data are stored for each one of a plurality of preselected intervals, and an indication or warning is given to the systems manager when performance data, or when a selected parameter exceeds a preselected threshold.
Abstract:
A card extender unit for a computer housing including first and second card extender sections which mount the card extender in position in the computer housing. The card extender includes a housing including first and second sections which support a printed circuit board having one or more high wattage, integrated circuits. One of the card extender sections includes a flow direction channel intake for directing air generated by an internal housing fan over one or more of the high wattage, integrated circuits mounted on the printed circuit board.
Abstract:
A circuit for connecting the power supply output of a computer to ground when the system is shut down to counter adverse effects of backfeed voltage which includes a MOSFET between the power supply output and ground. In one embodiment the MOSFET is switched on by a signal that deactivates the system power supply. In an alternative embodiment, two MOSFETs are used. The first MOSFET is controlled directly by the power supply output and shorts the second MOSFET's gate to ground when the power supply output generates a significant voltage. If the second MOSFET's gate is grounded, the MOSFET deactivates and opens a circuit between the power supply output and ground. When the power supply is turned off, the second MOSFET activates and grounds the power supply output. A resistor between the power supply output and ground allows the power supply to generate five volts when the system is power cycled and deactivate the second MOSFET.
Abstract:
A soft switching circuit gradually connects an audio signal to zero reference level to mute the audio signal, or connect a filter to enable the filter. A MOSFET is connected between the audio signal and the zero reference level. A resistor-capacitor circuit is connected to the gate of the MOSFET and receives the MUTE or FILTER* signal from the computer system. When the MUTE or FILTER* signal changes condition, the RC circuit provides a signal to the MOSFET gate that changes relatively gradually. Consequently, the drain-to-source resistance of the MOSFET also changes from short circuit to open circuit or vice versa relatively gradually.
Abstract:
An apparatus which converts burst mode bus cycles into single cycle mode cycles and converts separate address and data strobe signals into a single address strobe in a computer system. The apparatus also receives an address strobe signal, a number of address signals and the length of the burst when a device begins a burst cycle. After the first cycle of the burst transfer is complete, the apparatus initiates each subsequent cycle comprising the burst transfer by incrementing the address signals and providing additional address strobe signals until the burst is complete. The logic also facilitates address pipelining by monitoring a next address signal generated by the device. The apparatus monitors the separate address strobe and data strobe signals and generates the single address strobe signal on the next clock cycle after the address and data strobe signals are asserted. If only the address strobe signal is asserted at the beginning of a cycle, then the single address strobe signal is asserted only after valid data is available on the bus and the data strobe signal is asserted. The apparatus also monitors next address signals generated by the device to facilitate pipelining.
Abstract:
For use with a computer system having an intelligent mass storage disk array subsystem, including a microprocessor controller, a method for the distribution of data within the disk array based upon logical commands issued by the computer system. The disk controller reads a logical command and translates the commands into multiple drive specific commands, including drive physical parameter information such as head, sector and cylinder selection. The calculation of these physical parameters is based upon a number of factors including the operating system installed in the computer system, the type of interleave scheme, if any, specified by the computer system configuration, and disk specific parameters. The physical drive requests are then placed in a queue and executed by the microprocessor controller. The method also encompasses a method for creating a disk array configuration to be loaded on all disks within the array based on existing valid disk array information and configuration information maintained by the computer system.
Abstract:
An attachment unit interface electrical connector which includes a slide latch which is moveable between open and close positions utilizing a pivotally mounted tab member. The pivotally mounted tab member is mounted onto the slidably mounted latch so that the latch member is accessible even when the attachment unit interface female connector is attached to a male connector in an area of confinement.