Abstract: The present invention provides an improved measuring circuit for measuring a current of an inductor with minimum losses and errors. According to one embodiment of the invention, the measuring circuit comprises an op-amp, a RC network connected in a feedback loop of the op-amp, and a scaling resistor connected in series to one of the input terminals of the op-amp. By setting the RC constant of the RC network to be equal to the ratio of the inductor value over its internal resistance value, the inductor current can be derived independent of the frequencies of AC signals.

Abstract: The present invention provides an improved measuring circuit for measuring a current of an inductor with minimum losses and errors. According to one embodiment of the invention, the measuring circuit comprises an op-amp, a RC network connected in a feedback loop of the op-amp, and a scaling resistor connected in series to one of the input terminals of the op-amp. By setting the RC constant of the RC network to be equal to the ratio of the inductor value over its internal resistance value, the inductor current can be derived independent of the frequencies of AC signals.

Abstract: A buck converter has an input circuit for receiving an input signal, a controller connected to and controlling the input circuit, a switch controllable by the controller for switching on/off, a current storage element connected to the input circuit and the switch, and an output voltage storage element connected to the current storage element for connecting in parallel with a load. In a charging phase, the controller causes (a) the input circuit to allow the input signal to pass through for provision to the load via the current storage element and (b) the switch to switch off (becoming an open circuit). In a discharging phase, the controller causes (a) the input circuit to decouple from the input signal and (b) the switch to switch on (become a short circuit), so that (c) current flows within a loop formed by the switch and the current storage element.

Abstract: An architecture security fuse circuit is disclosed for securing the architecture of a configurable programmable logic device. The storage element of the circuit is a floating gate transistor cell. Data stored in the cell is determined by the amount of charge trapped within the oxide-isolated polysilicon floating gate region. The security fuse is initialized (erased) during device fabrication to allow access to device architectural data. Such initialization is accomplished by a technique that the device user cannot duplicate, via an extra probe pad accessible only during wafer probe. To deter the effects of floating gate charge loss which may occur during subsequent fabrication steps, the fuse circuit is adapted to provide a reduced memory cell read voltage, thus providing greater margin against thermally defeating the security fuse. A regenerative feature is provided to strengthen the erased cell during every device "clear" cycle.

Abstract: A system for generating an aesthetically pleasing abstract display on the screen of a color television receiver in timed relation to an audio signal derived from music or the like employs a filter network to divide the audio signal into a plurality of separate frequency bands. These signals are provided to the inputs of three modulators along with video pattern signals developed by a digital/analog mapping network connected to the outputs of various stages of an oscillator driven counter chain. The same counter chain produces the horizontal and vertical synchronization signals for the receiver so that the display is generated in timed relation to the raster scan of the television receiver. The three modulators receive certain of the audio signals and certain of the analog signals and their outputs are provided to the three chrominance inputs of the receiver either directly or via an RF transmitter which allows connection to the antenna of the TV set.

Abstract: A text editing system is provided in which a central station communicates a video signal, timing signals, and control signal to a remote station by way of a single communication pathway for subsequent display on a cathode ray tube at the remote station and wherein keyboard information may be communicated from the remote station to the central station across the same communication pathway. The video signal from the central station includes conventional horizontal and vertical synchronization pulses which are encoded prior to transmission to the remote station and decoded at the remote station.