Abstract: A slew rate control system for a circuit includes a temperature sensitive device generates a temperature signal. A temperature dependent current source generates a first current source signal. A slew rate controller activates in response to the temperature signal when the temperature exceeds a first threshold. The slew rate controller then generates a slew rate control signal by adjusting slew rate as a function of the temperature signal. The slew rate controller then activates the temperature dependent current source in response to the slew rate control signal.

Abstract: A slew rate control system for a circuit includes a temperature sensitive device generates a temperature signal. A temperature dependent current source generates a first current source signal. A slew rate controller activates in response to the temperature signal when the temperature exceeds a first threshold. The slew rate controller then generates a slew rate control signal by adjusting slew rate as a function of the temperature signal. The slew rate controller then activates the temperature dependent current source in response to the slew rate control signal.

Abstract: In a vehicle having an engine and an ignition system, a sensing circuit is provided for sensing the ignition voltage and providing this sensed signal to various operating modules of the vehicle. The sensing circuit includes a diode/resistor filter that provides a filtered voltage signal at a first output node. A compensation circuit is provided that compensates voltage errors introduced by the filter circuit. The compensation circuit includes a second diode that has substantially identical electrical performance characteristics as the first diode, and that is preferably mounted on a common substrate. A voltage signal at a second output node between the second diode and the filter circuit is indicative of the voltage drop across the second diode, which is further representative of the voltage error introduced by the filter circuit. In one embodiment, the operating module receiving the ignition voltage signal is configured to receive voltage signals at the first and second output nodes.

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: The firing circuit of an inflatable restraint system is tested to verify operation of two FETs in series with a squib which are used to apply current to the squib. For the test the squib is biased to an intermediate voltage and each FET is turned on alone to apply battery or ground voltage to the squib. High and low voltage detectors sense the voltage excursion past respective thresholds to verify FET operation. A current detector for each FET senses a short when its FET is conducting, and a logic circuit immediately turns off the FET to result in a very brief FET on time. In addition, the voltage detectors may be used to detect shorts prior to FET testing and also to turn off or hold off the FETs when a high or low voltage is detected upon FET testing.

Abstract: The firing circuit of an inflatable restraint system is tested to verify operation of two FETs in series with a squib which are used to apply current to the squib. For the test the squib is biased to an intermediate voltage and each FET is turned on alone to apply battery or ground voltage to the squib. High and low voltage detectors sense the voltage excursion past respective thresholds to verify FET operation, and a logic circuit immediately turns off the FET to result in a very short FET on time. If a short is present before the FET is commanded on, a detector and the logic circuit prevents FET conduction to avoid firing or degrading the squib.