Abstract: A method for micromachining the surface of a silicon substrate which encompasses a minimal number of processing steps. The method involves a preferential etching process in which a chlorine plasma etch is capable of laterally etching an N+ buried layer beneath the surface of the bulk substrate. Such a method is particularly suitable for forming sensing devices which include a small micromachined element, such as a bridge, cantilevered beam, membrane, suspended mass or capacitive element, which is supported over a cavity formed in a bulk silicon substrate. The method also permits the formation of such sensing devices on the same substrate as their controlling integrated circuits. This invention also provides novel methods by which such structures can be improved, such as through optimizing the dimensional characteristics of the micromachined element or by encapsulating the micromachined element.

Abstract: Large reserve capacitors store energy sufficient to operate the firing circuit and the deployment circuit for an SIR in the event of loss of battery or ignition voltage in a crash. A voltage doubling or tripling circuit charges the reserve capacitors. Normally the capacitors are isolated from the deployment circuit to minimize the load on the charging circuit. An isolation circuit detects the loss of ignition voltage and then connects a reserve capacitor to the deployment circuit for continued control operation.

Abstract: A supplemental inflatable restraint system has a deployment algorithm which is enabled when a threshold acceleration is reached and then, based on subsequent measured acceleration data, determines whether and when to deploy an air bag. Rough road conditions produce accelerations which can enable the algorithm and then produce a reset event to terminate the algorithm. Reset events are each stored for a short time and the number of unexpired reset events is a measure of the rough road condition. The deployment calculation is adjusted to delay deployment for a time proportional to the number of reset events to allow gathering of additional acceleration data for the deployment decision.

Abstract: A system for anti-lock brake and traction control has a control circuit comprising a microprocessor on a silicon die. Inputs from several variable reluctance wheel speed sensors are multiplexed to a single channel on the same die for signal processing including diagnostics, A/D conversion, square wave generation for each sensor by a state machine, and wheel speed determination from the square waves. The diagnostics include detecting sensor and harness short and open circuits by comparison of signals to programmable thresholds and fault timing and latching by gauging open and short signals against programmable time limits. Common mode noise rejection is accomplished by detecting common mode aberration and disabling an A/D converter during the aberrations. Other diagnostics include inputting known artificial signals at sensor inputs or wheel speed circuit inputs and checking for expected outputs, or by calculating wheel speed in parallel paths having the same square wave inputs and using different algorithms.

Abstract: A printed circuit board on the rear of an automotive instrument cluster is covered by a flat panel of polystyrene in contact with the circuit board to protect circuit components against electrostatic discharge. Openings in the panel allow large components which are not sensitive to ESD to protrude beyond the panel.

Abstract: This invention includes a method of making a bridge-supported accelerometer structure. A first wafer is worked, preferably by bulk micromachining, to provide a proof mass supported by a thin membrane on all sides. The thin membrane has the same thickness as the bridges to be defined therein. The first wafer is bonded to a second wafer having a cavity formed therein. The first wafer is then worked, preferably by plasma etching, to delineate bridges in the thin membrane. The cavity in the second wafer provides damping of the proof mass which reduced bridge breakage as portions of the thin membrane are removed leaving the final bridge-supported accelerometer structure. Combining the two wafers together prior to delineating the bridge provides for handling and processing of a much less fragile structure than the first wafer alone with bridges delineated therein.

Abstract: A process for silicon wafer-to-wafer bonding at temperatures lower than 500.degree. C. has been developed. It consists of (1) treating the cleaned surfaces to make them smooth and hydrophilic, (2) initiating the bond by making intimate contact between wafers and (3) enhancing the bond strength at elevated temperatures. This bonding process can be applied to sensor packaging.

Abstract: A motor vehicle is equipped with an infrared camera for viewing roadway conditions in terms of a thermal image, and outputs a video signal to a head up display (HUD) which projects the camera view to the operator via the windshield or other combiner to display a virtual image in the operator's field of view. The HUD is configured to magnify the image to the same size as the visual or real scene, and compensates for camera and windshield distortion. The virtual image is presented above or below the real scene or may be superimposed on the real scene. A video processor allows selection of only the warmest objects for display.

Abstract: A supra-passivant grid is disclosed which is capable of conducting residual charge from the surface of an integrated circuit and eliminating generic leakage effects on sensitive circuitry below.

Abstract: A method for testing gauges includes applying a rotation signal to the gauge. An AC input signal is superimposed on a first coil of the gauge. A second coil of the gauge is monitored to detect a coupled AC output signal. The rotational signal is varied while the AC output signal is monitored. The operational status of the gauge is determined responsive to the AC output signal and a process output signal indicative of the operational status is provided.

Abstract: Absolute engine position sensing is provided by monitoring the temporal relationship of energization of multiple spark plugs sharing a common source of drive energy in a direct ignition application. The spark plugs are connected across the source with opposing electrical polarity, and the relative time of discharge across the plugs compared by sensing the time and polarity of high speed transient activity in proximity to the source.

Abstract: Varying the selection and play of tracks on a CD in non-sequential order includes a CD mechanism (12) with which a processor (16) communicates, a keyboard (17) having a shuffle play key (18) for user actuation, and a disc and track display (19). The processor (16) generates a shuffled selection offset (T.sub.n) from a deterministic function based upon a sequence number (S.sub.n) and a random seed (Seed). The deterministic function includes performance of plurality of binary operations which may include bit inversions, exclusive OR with an N-bit constant, N-bit rotations, bit swapping, one to one substitutions, and modulus additions and subtractions. The generated sequence plays all selections before any selection is repeated, allows the user to replay any past selection or skip to any unplayed selection while maintaining the same order, requires minimal memory and execution time, and is suitable for use with single-disc CD players and multi-disc CD changers.

Abstract: An apparatus for fuel level display systems comprises a fuel level sender providing a fuel level signal, a short period filter for filtering the fuel level signal through a short time constant filter, a long period filter for filtering the fuel level signal through a long time constant filter, a signal selector for selecting the long period filter output if the fuel level is above a trip point and for selecting the short period filter if the fuel level is below the trip point, and a display device for displaying a level of fuel in the tank in response to the selected signal.

Abstract: An apparatus for providing an EEPROM programming signal, comprises a charge pump circuit for receiving a programming input signal on a programming input line and for charging up a gate drive voltage signal in response to a rising edge of the programming input signal. A transistor that includes a gate coupled to the gate drive signal couples the programming input line to a programming output line, which is coupled to an EEPROM. A ramp control circuit including (i) a capacitor and (ii) a transistor controlling the flow of current through the capacitor, is coupled to the programming output line for regulating a ramp-up rate of a programming output signal on the programming output line. A ramp-down circuit is coupled to the programming input line and to the programming output line and is responsive thereto for providing a ramp-down of the programming output signal after the programming input signal goes low.

Abstract: A vehicle controller in which inputs from several wheel speed sensors are used to compute wheel speed. A redundant circuit in the controller receives the sensor input signals and computes wheel speed in a different, software intensive, way. The primary and redundantly computed wheel speeds are compared to validate the primary controller circuitry and the portion of the controller used to process compute the redundant speed signal. To additionally verify proper calculation of wheel speed, the system is tested when the vehicle is at rest by applying an artificial sensor signal to the control input and then checking to see whether the controller determined the correct wheel speed.

Abstract: A method is provided for flip-chip bonding a flip chip to a substrate, which may be a ceramic substrate, printed wiring board, flexible circuit, or a silicon substrate, in which a number of input/output solder bumps are reflowed to both bond the flip chip to the circuit board as well as provide the necessary electrical connection between the flip chip and the circuit board's circuitry. The method enables the height of the input/output solder bumps to be closely controlled thereby providing sufficient spacing between the chip and its substrate, thus optimizing the cleanability and stress relief of the package. Generally, the preferred method involves the use of non-input/output, or "dummy" solder bumps which are present in sufficient numbers to overcome the tendency for the input/output solder bumps to draw the flip chip excessively close to the circuit board.

Abstract: A power supply for a VF display generates a DC filament voltage from a battery by either a switched transformer supply or a monolithic regulator circuit. Where a higher-than-battery voltage is needed for anode and grid voltages, another monolithic regulator circuit or the switched transformer is used. An H-switch develops an alternating voltage from the DC voltage and applies it to the display filament. A controller for the H-switch is a logic circuit including flip-flops which toggle in response to a low frequency pulsed dimmer signal to synchronize the filament half cycles with the dimmer phases. Slew rate control ramps the H-switch control signal to produce a trapezoidal waveform in the filament current having reduced radio frequency emissions.

Abstract: A climate control system for the interior of a vehicle includes infrared sensing to measure thermal level therein and to provide a signal to the system control for establishing and maintaining the thermal level to a level preset by a vehicle occupant. The viewing field and admissibility of the infra-red sensor determines the composition of the signal by controlling the objects, surfaces, area and radiation included in the field. Appropriate selection of viewing field and admissibility integrates into the signal corrective factors for external climatic conditions and solar re-radiation within the vehicle.

Abstract: An opening in a vehicle dash pad allows a HUD reflecting element or mirror to be retracted into the dashboard when not in use. A cover panel hinged to the dash pad supports the mirror and closes the opening when retracted. The panel is joined to a gear arrangement which is controlled by a motor for moving the panel and mirror between storage and operating positions. The mirror is coupled to the panel by a ball joint and the mirror is adjusted about two tilt axes by motor-driven cams for positioning the HUD image in the view of the operator.

Abstract: An apparatus and method for deployment of an air bag installed in an automotive vehicle. The control includes a senor for sensing vehicle deceleration due to a collision and a processor operatively connected to the sensor. The sensor generates a deceleration signal which is analyzed by the processor. The processor calculates velocity and signal energy from the deceleration signal, and compares the velocity and signal energy to predefined velocity and energy thresholds, respectively. The processor also generates a deployment signal when both the velocity and energy signals exceed the respective thresholds. In the method for controlling the deployment of an air bag, vehicle deceleration due to a collision is sensed and a deceleration signal is generated therefrom. The velocity signal and energy signals are then calculated and compared to the respective predefined velocity and energy thresholds.