Abstract: A control circuit for an air-bag mounted in a motor vehicle comprises an acceleration sensor for producing an acceleration signal indicative of acceleration of the vehicle, an ignition timing circuit for processing the acceleration signal to predict the time when a passenger's head will reach a front surface of the air-bag in fully deployed condition and producing a first air-bag deploying signal in accordance with the predicted time, and a damage discrimination circuit for processing the acceleration signal and judging the need of activation of the air-bag when the cumulative effect of the acceleration exceeds a predetermined limit. The damage discrimination circuit produces a second air-bag deploying signal when judging the need of activation of the air-bag. A so-called AND circuit is further employed which actually activates the air-bag when receiving the first and second air-bag deploying signals concurrently.

Abstract: A control circuit for an air-bag mounted in a motor vehicle comprises an acceleration sensor for producing an acceleration signal indicative of acceleration of the vehicle, an ignition timing circuit for processing the acceleration signal to predict the time when a passenger's head will reach a front surface of the air-bag in fully deployed condition and producing a first air-bag deploying signal in accordance with the predicted time, and a damage discrimination circuit for processing the acceleration signal and judging the need of activation of the air-bag when the cumulative effect of the acceleration exceeds a predetermined limit. The damage discrimination circuit produces a second air-bag deploying signal when judging the need of activation of the air-bag. A so-called AND means is further employed which actually activates the air-bag when receiving the first and second air-bag deploying signals concurrently.

Abstract: An occupant protecting device for a motor vehicle, which inflates an air-bag system reliably to protect occupants in the event of a collision with high reliability. The occupant protecting device includes an acceleration sensor for sensing an acceleration signal of a vehicle in the event of collision with another vehicle or the like, a signal processor for detecting a collision waveform from an acceleration signal output from the acceleration sensor, a comparator for determining whether or not the output signal of the signal processor exceeds a preset level to produce a trigger signal when it exceeds the preset level, a latch circuit for latching the trigger signal from the comparator, and a firing circuit for operating an occupant protecting unit in response to a drive signal from the latch circuit.

Abstract: An occupant protecting device for a motor vehicle, which inflates an air-bag system reliably to protect occupants in the event of a collision with high reliability. The occupant protecting device includes an acceleration sensor for sensing an acceleration signal of a vehicle in the event of collision with another vehicle or the like, a signal processor for detecting a collision waveform from an acceleration signal output from the acceleration sensor, a comparator for determining whether or not the output signal of the signal processor exceeds a preset level to produce a trigger signal when it exceeds the preset level, a latch circuit for latching the trigger signal from the comparator, and a firing circuit for operating an occupant protecting unit in response to a drive signal from the latch circuit.

Abstract: The invention relates to circuits which increase the reliability of a passenger restraint system. In one embodiment, the connection layout with respect to a main power source, such as a vehicle battery, prevents accidental activation in the event certain portions of the wiring become grounded and which enables the activation when required even when some of the wiring is cut. Another embodiment increases the time for a which a diagnostic system can be maintained operative should the connection with the vehicle battery be lost. A third and more complex embodiment features circuits which can estimate the amount of damage which has occurred to the vehicle and predict the displacement of person under the influence of the acceleration (deceleration) caused by a collision.