Abstract: An improved auto-zeroing circuit for reducing offset currents from high impedance CMOS current drivers. The Auto zero circuit of the present invention contains means to disconnect the output of the current driver from its low impedance load, means to substantially simultaneously connect a capacitor to the output of the current driver, and means to use the output voltage of the current sources during the zeroing mode to adjust the voltage on the capacitor. The capacitor voltage is then used to adjust either of the two output current sources to reduce the offset currents.

Abstract: A method and circuit for automatically centering the control loop bias current by sensing and “memorizing” the total steady state bias current used by the function block (VGA or VCO) through the use of both digital and analog memory elements. The present invention uses an auto-centering, high-impedance current driver to supply the bias current. This current driver cancels out offset currents by exploiting the high output impedance nature of a CMOS current driver using cascoded or resistor source de-generated FET devices.

Abstract: An integrated circuit architecture and test methods for use in designing, fabricating and testing mixed-signal application specific integrated circuits. The architecture comprises a plurality of mixed-signal integrated circuits, bidirectional buffers coupled to the integrated circuits that provide for circuit reconfigurability, a bidirectional digital/analog test bus, and a serial test controller coupled to the buffers that controls normal operation and testing of the integrated circuits. The controller and plurality of buffers cooperate to couple signals from signal pads to the integrated circuits to provide for "normal" operation thereof, and to re-route external test signals applied to selected signal pads to the integrated circuits to permit testing. Logic in the buffers provides for functional configurability, enabling them to be logically altered under control of the controller, and allowing the test bus to be connected directly to signal pads.

Abstract: An apparatus for processing data, such as liquid level data in a motor vehicle containing a liquid storage tank, comprises a liquid level sensor for developing a signal indicative of instantaneous liquid level in the storage tank, circuitry for processing the instantaneous liquid level signal, including asymmetrical filtration of the instantaneous liquid level signal, to provide a process output signal, and a display apparatus for displaying an indication of the level of liquid in the storage tank in response to the process output signal.

Abstract: An integrated circuit including a serial interface (12) having a nonvolatile memory (30) coupled to a and configuration of circuit boards and entire systems. A configurable circuits (10) containing switches, resistors, capacitors or digital logic devices has an unique identification code and is electrically configured by connection to a nonvolatile memory (30). An interrogation shift register (38) and a configuration data shift register (36) are serially connected to receive a serial bit stream (50) containing an interrogation code section and a configuration data section. The interrogation code, which is identical to the identification code of a selected one of the configurable circuits, is compared with the circuitidentification code to provide a match pulse (42) that enables a program signal to initiate transfer of data from the data shift register (36) to the nonvolatile memory (30).

Abstract: A circuit including a sender providing a sender output signal responsive to a vehicle parameter, circuitry for providing an adjustable reference, circuitry for comparing the output signal to the adjustable reference and providing a comparison output signal therefrom, an up/down counter for filtering the comparison output signal, and circuitry for providing an indicator control signal in response to the filtered output signal and for controlling the adjustment of the adjustable reference, provides a signal to a vehicle operator that is both filtered and has hysteresis to minimize repeated switching of the signal between two states.

Abstract: A circuit disclosed maintains ratiometric analog inputs to an integrated circuit using a network of resistors, some of which are external to the integrated circuit and some of which are internal to the integrated circuit, reducing expense. The analog inputs maintain a fixed ratio during fluctuations in supply voltage and fluctuations in temperature.