Abstract: A backup power supply for a restraint control module is disclosed that includes a main power source that is connected to a backup power source charging circuit. A boost converter control and driver circuit is connected with the main power source and the backup power source such that the boost converter control and driver circuit controls the charging of the backup power source with the main power source during normal operation. A backup power supply control and driver circuit is connected with a backup power supply switching device. The backup power supply control and driver circuit switches the source of power from the main power source to the backup power source when the backup power supply control circuit senses a loss of power from the main power source.

Abstract: A non-inverting dual voltage regulation set point power supply for a restraint control module is disclosed that includes a main power source. A regulated voltage generation circuit connected with said main power source for generating a regulated output voltage having an upper set point and a lower set point. A buck switch connected to said main power source and said regulated voltage generation circuit for bucking the regulated output voltage generated by said regulated voltage generation circuit to said upper set point if said voltage supplied from said main power source is greater than said upper set point. A boost switch connected with said regulated voltage generation circuit for boosting the regulated output voltage generated by said regulated voltage generation circuit to said lower set point if said voltage supplied from said main power source is less than said lower set point.

Abstract: A method of testing a high-side driver and a low-side driver in an airbag squib circuit includes preliminary testing of squib resistance and squib leakage for a plurality of trials. Next, one of the drivers is turned on while keeping the other one of the drivers off. A current-limited power supply supplies an intermediate voltage to a squib terminal and the voltage at the terminal is continuously compared with a predetermined voltage range which includes the intermediate voltage. The one driver is turned off in response to the voltage at the point being outside the predetermined voltage range, thereby detecting that the one driver is operating properly. If the voltage at the point remains in the predetermined voltage range for a predetermined time period, then the one driver is turned off and an indication is made that the one driver has failed. If the first driver passed, then the other driver is tested in the same manner.

Abstract: A non-inverting dual voltage regulation set point power supply for a restraint control module is disclosed that includes a main power source. A regulated voltage generation circuit connected with said main power source for generating a regulated output voltage having an upper set point and a lower set point. A buck switch connected to said main power source and said regulated voltage generation circuit for bucking the regulated output voltage generated by said regulated voltage generation circuit to said upper set point if said voltage supplied from said main power source is greater than said upper set point. A boost switch connected with said regulated voltage generation circuit for boosting the regulated output voltage generated by said regulated voltage generation circuit to said lower set point if said voltage supplied from said main power source is less than said lower set point.

Abstract: A backup power supply for a restraint control module is disclosed that includes a main power source that is connected to a backup power source charging circuit. A boost converter control and driver circuit is connected with the main power source and the backup power source such that the boost converter control and driver circuit controls the charging of the backup power source with the main power source during normal operation. A backup power supply control and driver circuit is connected with a backup power supply switching device. The backup power supply control and driver circuit switches the source of power from the main power source to the backup power source when the backup power supply control circuit senses a loss of power from the main power source.

Abstract: A method and system for measuring the capacitance of a backup power source in a backup power supply system is disclosed by the present invention. The regulated output voltage is set to a nominal regulated output voltage during normal operation and then adjusted to a predetermined regulated output voltage during a capacitance measurement. A pair of predetermined loads is connected to the backup power source in consecutive order for discharging energy from the backup power source. A counter is used to count the time that elapses before the regulated output voltage reaches the lower regulated output voltage or the backup power supply system begins regulating. The resulting counts are used by a main control unit, together with several other known values, to determine the capacitance of the backup power source.

Abstract: A circuit 17 for interfacing with a sensor 18 having a sensor input current and a modulated sensor current signal corresponding to a sensed condition. A control module 20 is coupled to the sensor 18 and receives the sensor current signal. The control module 20 converts the sensor current signal to a modulated signal having a pulse width with a duration corresponding to the sensed condition. The control module 20 counts a time corresponding to the pulse width. The time corresponds to the sensed condition.

Abstract: A method of testing a high-side driver and a low-side driver in an airbag squib circuit includes preliminary testing of squib resistance and squib leakage for a plurality of trials. Next, one of the drivers is turned on while keeping the other one of the drivers off. A current-limited power supply supplies an intermediate voltage to a squib terminal and the voltage at the terminal is continuously compared with a predetermined voltage range which includes the intermediate voltage. The one driver is turned off in response to the voltage at the point being outside the predetermined voltage range, thereby detecting that the one driver is operating properly. If the voltage at the point remains in the predetermined voltage range for a predetermined time period, then the one driver is turned off and an indication is made that the one driver has failed. If the first driver passed, then the other driver is tested in the same manner.

Abstract: A sensor system for detecting impacts to a vehicle, allowing for actuation decisions of passive restraint devices. The sensor system includes one or more piezoelectric sensor assemblies (42), each including a coaxial piezoelectric cable (44) contained within a tube housing (54), which is mounted to a structural member of the vehicle. The sensor system may also include accelerometers (36, 38) that are also in communication with the restraints control module (40) and employed in combination with one or more piezoelectric sensor assemblies (42). Further, the sensor system may include diagnostics for monitoring one or more of the sensor assemblies (42) in order to detect a sensor failure, while not interfering with the impact signals from the sensor assemblies (42).