Analog signal processing system for determining airbag deployment

Abstract

An analog signal processing system for determining airbag deployment includes a first low pass filter receiving a conditioned analog accelerometer signal and providing an analog acceleration signal therefrom. A first comparator/latch circuit receives the analog acceleration signal and provides a first signal to a logic circuit. The analog acceleration signal is further provided to a first integrator which converts the signal to a first velocity signal and provides the first velocity signal to a second comparator/latch circuit which provides a second logic level signal to the logic circuit. A second low pass filter receives the analog acceleration signal and provides a low frequency analog acceleration signal to a third comparator/latch circuit which provides a third signal to the logic circuit. The low frequency analog acceleration signal is further received by a second integrator circuit which converts the signal to a second velocity signal and provides the second velocity signal to a fourth comparator/latch circuit which provides a fourth signal to the logic circuit. The logic circuit performs a logic operation on the various logic level signals to provide an airbag deployment signal therefrom. Each comparator/latch circuit has a comparator threshold value associated therewith provided by a threshold circuit. The system is enabled for a preset time period after detecting a predefined acceleration level to provide a time-independent analog algorithm for evaluating the analog acceleration signal for possible airbag deployment.