Abstract: A mirror motor is coupled to the mirror by a ratchet coupling. A feedback signal representing the drive current of the mirror motor is digitally sampled and analyzed by a type of Fourier transform, preferably a discrete cosine transform, to determine the low frequency components of a current pulse which arises when the mirror reaches a stop at its end of travel and the ratchet operation begins to occur. A fundamental component is due to the pulse rise. Motor current is terminated if that component exceeds a threshold for a set time. A harmonic component is due to the ratchet action and pulse fall. Motor current is terminated if the harmonic element reaches another threshold.

Abstract: A voltage boost circuit having dual voltage outputs and a single input receives a DC voltage from an external source. The input voltage is boosted to provide a constant voltage at the first output at a level higher than the voltage input and to provide a constant voltage output at the second output. A switch is coupled to the output of the inductor for controlling the current flow to the second output.

Abstract: An existing vehicle seat design is equipped with strain gauges welded to structural seat members to sense occupant seated weight. A microprocessor compensates for preload on the sensors and multiplies each signal by an empirically determined gain, and then combines the gauge outputs. The combined output is low pass filtered to avoid motion induced errors. The measured occupant seated weight is used by decision logic to decide whether to allow passenger airbag deployment.

Abstract: A differential pressure transducer housing assembly comprising a sensor housing and a connectable cap member. The cap member includes an input port, a post and at least one coupling member. The sensor housing includes an opening for receiving the post of the cap member, and a bracket for engaging the coupling member. When the cap member is connected to the sensor housing, the coupling member and the bracket engage such that the cap member and the housing are fixed in register with respect to each other. Because the cap member is connectable to the sensor housing, numerous cap members having different input port orientations are possible, thus providing flexibility of design with respect to the entire sensor assembly.

Abstract: An improved pressure sensor assembly includes a low-cost pressure port comprising a casing formed of cold rolled steel, a small stainless steel insert and an O-ring. The casing has a threaded slug at one end for attaching the sensor assembly to the wall of a pressure vessel and an annular cup at the other end. The annular cup has a hex-shaped periphery to facilitate installation and removal of the sensor assembly, and defines a cylindrical interior cavity including an annular recess in which the O-ring is disposed. The stainless steel insert has a base portion disposed within the cylindrical cavity atop the annular recess so as to compress the O-ring between the insert and casing, and a neck portion that extends out of the cavity to form a pedestal to which the stainless steel pressure sensor element is welded. The insert is retained relative to the casing by a staking operation in which a portion of the casing is deformed against the neck of the insert.

Abstract: A transmitter for a differential serial data communication bus incorporating the CAN format includes features for minimizing radiated emissions. The transmitter includes a second order input filter for establishing a slew rate of pulses edges and for rounding corners, a first amplifier for attenuating and level shifting the filtered input to produce a first bus output, and a second amplifier coupled to the first bus output for producing a second bus output mirroring the first. The second amplifier has a high unity gain frequency and a closed loop configuration, both for minimizing phase differential of the two outputs.

Abstract: A conductor (112) and method for attaching a surface mount device to the conductor (112), in which solder bumps (16) formed by the method are characterized as being accurately located on the conductor (112) and having a bump height and shape that provides stress relief during thermal cycles, minimizes bridging between adjacent bumps (16), allows penetration of cleaning solutions for removing undesirable residues, and enables the penetration of mechanical bonding and encapsulation materials between the chip and its substrate (10). Such benefits are achieved by forming the conductor (112) of a nonsolderable material, on which a solderable pillar (114) is formed. The pillar (114) is selectively formed to have a shape that determines the distribution and height of the solder bump (16) on the conductor (112).

Abstract: A clearance gauge comprises a thin foil rolled into a tubular coil at one end and having a flat tab extending from the coil, the coil windings being secured by a layer of adhesive. The gauge is attached via the tab to one of a pair of relatively movable parts and is deformed by compression between the parts to assume a dimension equal to the clearance between the parts. The foil has a low yield strength so that the coil substantially retains the dimension for later measurement to thereby afford a measure of the clearance.

Abstract: A voltage boost circuit having a voltage output and a single input receives a DC voltage from an external source which is fed to an inductor. The input voltage is boosted to provide a constant voltage at the output at a level higher than the voltage input. A switch is coupled to the output of the inductor for controlling current through the inductor to induce a boosted voltage across the inductor.

Abstract: The present invention provides, in a preferred embodiment, a method whereby resynchronization between a transmitter and receiver is activated intuitively by, and transparently to, an authorized user, including: transmitting at least a first message from the transmitter to the receiver; and, in response to the receiver receiving the first message, the receiver detecting the absence of synchronization between the transmitter and the receiver and performing a resynchronization procedure to restore synchronization between the transmitter and the receiver.

Abstract: An electrometer (20) for measuring an unknown DC potential finds particular utility in applications requiring a high input resistance and minimal current drain during measurement. The electrometer (20) employs a circuit containing a sampling diode (D1) and capacitor (C1). Prior to a measurement being taken, the capacitor (C1) is charged to a common-mode voltage and the diode (D1) is reverse biased to a potential approximating the unknown potential of the voltage source (30) to be measured. A switch (S1) is employed to momentarily cause current flow through the capacitor (C1) and to forward bias the diode (D1). The unknown potential is calculated from potentials associated with the sampling diode (D1) and the capacitor (C1). The calculation involves sampling the potential of the capacitor (C1) at precisely determined time delays.

Abstract: A SIR system has frontal air bags and side air bags both controlled by the same microprocessor. To guard against spurious deployment of side air bags with minimal software burden, a lateral accelerometer and an arming circuit detect side crash activity and apply an arming signal to a pulse accumulator circuit in the microprocessor which monitors the accumulator state to detect arming, thereby inhibiting deployment when the arming signal is absent. The arming circuit receives the accelerometer signal, removes the dc component which is subject to drift, adds a fixed offset voltage and compares the resultant signal to threshold values to produce an arming signal when a threshold is breached.

Abstract: A system for remotely controlling a desired door locking or other function in a vehicle or other protected environment has a transmitter and receiver for communicating a message including a sequence number, the code of a selected function to be performed and an authenticator. An algorithm in the transmitter and in the receiver has a cryptographic key and a seed code. Each algorithm generates the authenticator as a function of both the seed code and the function code; if the authenticators are equal, the message is valid. Upon each transmission the seed code is updated and the sequence number is incremented. The receiver updates its seed code according to the transmitted sequence number to keep the algorithm in synchronism. Upon manufacture the transmitter sends the initial seed code and key to the receiver to program the receiver. This data is sent without delay when the battery is first installed but later a time delay is imposed to prevent sending inadvertent program messages.

Abstract: A deployment control method for distributed architecture SIR system provides improved fault tolerance and ensures that signals generated by various remote sensor modules are properly considered in determining whether to deploy restraint devices. The deployment control method establishes a succession of states, wherein entry into each state is conditioned upon the achievement of predetermined criteria, and deployment of a respective restraint device is conditioned upon the successive achievement of each state. The states include an inhibit state, an enabled state, an armed state and a deployment initiated state. The predetermined criteria include correct occupant position, collision verification or safing, and collision severity. Deployment can only be initiated when the initiator module has been advised that all three criteria have been met within a given time constraint.

Abstract: A thick-film strain-sensing structure for a media-compatible, high-pressure sensor. The strain-sensing structure generally includes a metal diaphragm, at least one electrical-insulating layer on the diaphragm, an interface layer on the electrical-insulating layer, and at least one thick-film piezoresistor on the interface layer for sensing deflection of the diaphragm. The interface layer and the electrical-insulating layers are preferably formed by thick-film processing, as done for the piezoresistors. For compatibility with the metal diaphragm, the electrical-insulating layer has a CTE near that of the diaphragm. The interface layer is formulated to inhibit and control diffusion of the electrical-insulating layers into the piezoresistors. For this purpose, the interface layer is formed from a composition that contains, in addition to a suitable organic media, alumina, zinc oxide, and at least one glass frit mixture comprising lead oxide, a source of boron oxide such as boric acid, silica and alumina.

Abstract: A durable substrate subassembly for a high power transistor switching module. The substrate subassembly is durable because wire bonds to the semiconductor device electrodes are replaced with a soldered metal/ceramic composite conductor. The part of the composite conductor contacting the semiconductor device has a coefficient of thermal expansion close to that of the semiconductor device. The metal of the composite conductor is preferably a strip of copper foil. The ceramic portion is a layer of alumina on the copper foil that is generally coextensive with the semiconductor device electrodes.

Abstract: An apparatus for dampening movement of passivation material in an electronic module and a method for manufacturing an electronic module incorporating such an apparatus are disclosed. The apparatus includes a housing defining a cavity sized to contain an electrical circuit and a non-solid passivation material. The apparatus further includes means for limiting movement of the passivation material within the cavity in at least one direction. In a preferred embodiment, the limiting means comprises at least one dam.

Abstract: An aligned electronic circuit component assembly for attaching components onto larger mounting members at predetermined positions thereon are provided. The mounting or heat spreader members include shift resistant regions which are disposed in close proximity or substantially aligned with peripheral portions or edges of the component die when the die is placed in its predetermined position on an associated mounting or base member. The shift resistant regions can include non-linear edge surfaces, such as the edge surfaces around notches in the members, so as to provide areas on the base or heat spreader member which do not have solder thereon. It has been found that the surface tension of the liquid solder during reflow acts to provide a restraining force at the edge surfaces so as to restrain the electronic component from shifting from the desired position on the base member.

Abstract: A method and encapsulation material for encapsulating the solder joints of an IC device mounted on the substrate of an electronic circuit assembly. The encapsulation material is formulated to be sufficiently opaque to x-radiation to enable the use of x-radiation imaging techniques to detect air pockets and voids in the encapsulation material that might degrade the fatigue life properties of the solder joints encapsulated by the encapsulation material. For the purpose of enhancing the fatigue life properties of the solder joints, the encapsulation material contains a filler material dispersed in a polymeric material, such as an epoxy, such that the encapsulation material is characterized by a coefficient of thermal expansion approximately equal to that of the solder joints. The filler material contains a sufficient amount of an element to render the encapsulation material opaque to x-radiation.

Abstract: A transformer assembly in which an isolation transformer and two additional inductor elements of a series/parallel resonant converter are physically integrated in a cost and space-efficient design. The transformer and two inductors are integrated through the simultaneous control of the leakage inductance and the magnetizing inductance of the assembly. The primary and secondary windings of the transformer are wound in a prescribed manner on a closed-path ferromagnetic core, the magnetizing inductance of the unit being determined by the desired inductance of second inductor, and the leakage inductance of the unit being determined by the inductance of the first inductor, which predominates the total series inductance of the tank circuit. The desired magnetizing inductance is achieved by controlling an air gap disposed in the magnetic flux path of the core, while the desired leakage inductance is achieved by winding a certain portion of the secondary turns on a loosely coupled leg of the core.