Abstract: The present invention relates to an acceleration sensor which can be provided in a place with extreme ambient temperature variations, for example, near a vehicle engine, and an acceleration detecting system having the acceleration sensor, which are used to control an occupant protection device such as an airbag. In an acceleration sensor (1, 40, 50, 160), gain of an amplifier circuit (4, 5, 6, 41, 42, 43, 51) which differentially amplifies outputs of a piezo-electric element (3) is adjusted by temperature compensation means (9), and thereby an output-temperature characteristic of the piezo-electric element (3) is compensated. Also, a capacitor (8) is inserted in parallel with the piezo-electric element (3), and thereby a composite capacity is increased. By this, a lower cut-off frequency is set to a lower frequency without increasing resistor values of a bias resistor circuit (7).

Abstract: A control apparatus of an occupant protection device has at least one front acceleration sensor provided in a front part of a vehicle, in addition to a room acceleration sensor provided in a room of the vehicle. Whether the vehicle is in a collision requiring a drive of the occupant protection device is decided based on each of sensor outputs of the room and front acceleration sensors, respectively, and the occupant protection device is driven when the collision is detected based on at least one of the sensor outputs. Since the front acceleration sensor is provided in the front part of the vehicle, the front acceleration sensor detects a collision acceleration early and gives it to the control unit, even in case of a collision, such as the offset or an oblique collision, in which a collision acceleration transmitted to the room acceleration sensor may be weakened. Therefore, the control unit can exactly drive the occupant protection device without causing delay in collision detection.

Abstract: A control apparatus of an occupant protection device has at least one front acceleration sensor provided in a front part of a vehicle in addition to a room acceleration sensor provided in a room of the vehicle. The front acceleration sensor detects an acceleration of the vehicle and gives the control unit a sensor output representative thereof. The control unit, when the sensor output of the front acceleration sensor is a sensor output caused by a collision of the vehicle, detects a variational quantity of the sensor output of the front acceleration sensor based on sensor outputs of the front acceleration sensor at two different time points, and increases an integrated value of an acceleration signal of the room acceleration sensor based on the variational quantity. Then, when the integrated value of the room acceleration sensor exceeds a threshold value, the occupant protection device is driven.

Abstract: A control apparatus of an occupant protection device detects whether a vehicle is in a collision requiring to drive the occupant protection device based on at least one front acceleration sensor provided in a front part of the vehicle, in addition to a collision detection based on a room acceleration sensor provided in a room of the vehicle. When the collision is detected based on the front acceleration sensor, an integrated value of an acceleration signal of the room acceleration sensor is increased. Since the front acceleration sensor is provided in the front part of the vehicle, the front acceleration sensor detects a collision acceleration early and gives a sensor output to the control unit, even in case of a collision in which a collision acceleration transmitted to the room acceleration sensor may be weakened.

Abstract: A control apparatus of an occupant protection device, in addition to a room acceleration sensor provided in a room of a vehicle, has at least one front acceleration sensor provided in a front part of the vehicle. The front acceleration sensor, when detecting a predetermined collision acceleration, gives a detection signal to a control unit. The control unit sets a second threshold value lower than a first threshold value if the detection signal is input, and drives the occupant protection device when an integrated value of an acceleration signal of the room acceleration sensor exceeds the second threshold value. Since the front acceleration sensor is provided in the front part of the vehicle, even when a collision acceleration transmitted to the room acceleration sensor is weakened, the front acceleration sensor detects the collision acceleration early and gives the detection signal to the control unit.

Abstract: A charged voltage between the ground and a positive pole of backup capacitor 5 and a ground-casing voltage developed between the ground and a casing of capacitor 5 are determined. When the ground-casing voltage is smaller than a first value, it is judged that capacitor 5 has an opened circuit on its positive pole side; when the ground-casing voltage is larger than a second value, it is judged that capacitor 5 has an opened circuit on its negative pole side. A difference between the ground-casing voltage and the charged voltage is divided by the ground casing voltage so that a coefficient is obtained. When the coefficient is outside a predetermined range of values, it is judged that capacitor 5 is poor in capacitance, which makes it possible to determine, even in operation, whether capacitor 5 functions properly.

Abstract: A control system comprises an acceleration sensor for detecting an acceleration of a vehicle, an integral circuit for integrating a signal from the acceleration sensor, and a collision judgment circuit for comparing the integral value with a trigger threshold level and outputs a trigger signal when the integral value, which is increased in a decelerating direction, exceeds the trigger threshold level. A drive circuit of the control system includes an activator of the safety device for a vehicle, and a switching element which is connected to the activator in series and turned on in response to the trigger signal. The control system further comprises a band-pass filter for allowing passage of comparatively high particular frequency band components contained in the acceleration signal, and an adjustment circuit for adjusting the trigger threshold level based on the acceleration components which have passed the band-pass filter.

Abstract: A control system for a plurality of vehicle safety devices has a feeder circuit and a check current supplying circuit. A plurality of actuating elements are arranged in the feeder circuit in parallel relation, and at the same time, they are arranged in the check current supplying circuit in serial relation. When a switching element is turned ON in accordance with a trigger signal coming from a collision judging circuit, an electric current flowing through the feeder circuit is caused to flow through the actuating elements in parallel. The check current flows to the actuating elements in series. The voltage generated between opposite ends of the serial circuit of the actuating elements in the check current supplying circuit is compared with a predetermined allowable range of voltage in a malfunction judging current, and when the voltage between the opposite ends is outside the predetermined allowable range of voltage, a malfunction detecting signal is outputted from the malfunction judging circuit.

Abstract: A switching boosting circuit including a clock oscillating circuit having a Schmitt trigger inverter, a boosted-voltage inducing circuit which is actuated in a switching-operation mode in response to the output clock of the clock oscillating circuit to induce a boosted voltage, a capacitor which is charged by the boosted voltage from the boosted-voltage inducing circuit to store energy to be supplied to a load, and a feedback path for feeding back current whose intensity corresponds to the load from the capacitor to the clock oscillating circuit. The feedback current acts such that the duty ratio of the switching operation is set to be smaller than a predetermined reference duty ratio, and the feedback path includes a Zener diode for reducing the boosted voltage below a predetermined value.

Abstract: A system for controlling a safety device for a vehicle has a first and a second switching element connected in series in this order from a power source toward the ground. A condenser is interposed between a connecting point for both the first and second switching element and the ground in such a manner as to be in parallel relation to the second switching element. The actuating element for the vehicle safety device is connected in serial relation to the condenser between the connecting point and the ground. The control system further has an electric current supply control device. This electric current supply control device periodically effects ON/OFF control operations over the first and second switching elements.

Abstract: A control system for a vehicle safety device includes an acceleration detecting device for detecting the deceleration of the vehicle, an integrating device for integrating the deceleration from the acceleration detecting device, a collision judgment device for comparing the integral value, obtained by the integrating device, with a trigger threshold level so as to judge whether or not a collision has occurred, and for outputting an activation instruction signal when the collision judgment device judges that the collision has occurred, and a drive circuit responsive to the activation instruction signal from the collision judgment device so as to activate the vehicle safety device. The control system further includes a deceleration compensation device for adjusting the trigger threshold level in accordance with the deceleration in such a manner that the trigger threshold level becomes low when the deceleration is large and that the trigger threshold level becomes high when the deceleration is small.

Abstract: In a control apparatus for actuating a vehicle safety device in response to the specific change in the magnitude of acceleration/deceleration of the vehicle which occurs upon a collision, the output signal from the acceleration/deceleration sensor is processed to obtain detected vehicle speed data relating to the running speed of the vehicle, and the maximum value of a positive-going peak in the change in the detected vehicle speed data is detected to determine a reference level used for discriminating the occurrence of collision. The magnitude of the detected vehicle speed data is compared with the reference level, whereby it is discriminated whether or not a collision has occurred on the basis of the condition of the change in the detected vehicle speed.

Abstract: A control system for a vehicle safety device includes a pair of acceleration sensing circuits. The outputs of the acceleration sensing circuits correspond to a deceleration of the vehicle in a direction of running of a vehicle, and are in opposite phase with each other. A differential calculation device effects calculation in accordance with the difference between the outputs of the acceleration sensing circuits, so as to cause noises, applied to the acceleration sensing circuits, to cancel each other, thereby preventing an inadvertent activation of the vehicle safety device due to such noises.

Abstract: A compact watch dog timer circuit which includes a pulse period determining circuit (1) for generating a timer reset pulse if a period of an input pulse from an external machine falls within a tolerance range or beyond an upper limit of the tolerance range and no timer reset pulse if the period falls below a lower limit of the tolerance range; and a timer (2) for generating a signal for restoring the external machine to a predetermined condition when no timer reset pulse is fed from the pulse period determining circuit within a timer period which is set corresponding to the tolerance range.

Abstract: A control system for a vehicle safety device includes an acceleration sensing circuit, an analog collision detection system, a digital collision detection system, and a drive circuit which operates the vehicle safety device when the drive circuit simultaneously receives collision detection signals respectively from both of the analog and digital collision detection systems. A microcomputer of the digital collision detection system outputs test pulses to the acceleration sensing circuit, and checks at least one of the output of an integrating circuit of the analog collision detection system and an output of a comparator circuit of the analog collision detection system so as to detect a malfunction of the analog collision detection system, the outputs of the integrating circuit and the comparator circuit being produced in response to the test pulse.

Abstract: A method for checking the operability of a vehicular safety system which comprises an acceleration sensor for providing a pair of differential output signals, a first and second vehicle collision discriminators having a differential amplifier responsive to the pair of differential output signals, respectively, a pair of current controllers responsive to the first and second distriminators, respectively, whereby a firing current is supplied to a firing actuator through the pair of current controllers when the vehicle collision is detected. The method is characterized in that one of the differential amplifier is changed in arrangement so as to be able to respond to an in-phase input, and a test signal for making the acceleration sensor produce pair of check signals in phase is applied to the acceleration sensor. Then the operability of the safety system is checked on the basis of the potential developed at the firing actuator at that time without the activation of the actuator.

Abstract: In a vehicle safety device control apparatus having an energy reservoir, a current regulator for regulating the current supplied from the energy reservoir to a firing element of the safety device, and a controller for controlling the current regulator so as to supply energy for actuating the firing element in response to a vehicle collision, the current regulator is also controlled so as to supply a check current with a level insufficient to actuate the firing element to the fired element so as to produce a detection signal indicative of the condition of the firing element. The condition of the detection signal is checked by a first discriminator and the conditions of the channel and the firing element are determined. In the case where the capacity of the energy reservoir is not sufficient, the output voltage of the energy reservoir falls sharply when the check current is drawn therefrom. A second discriminator is provided to discriminate whether or not the capacity of the energy reservoir is sufficient.

Abstract: In a control system for actuating a vehicle air-bag, a data representing change in the detected vehicle speed is calculated on the basis of the acceleration sensed by a vehicle acceleration sensor. The data is compared with a reference signal depending upon a temperature relating to that of an actuating member of the air-bag to discriminate whether or not the change in the detected vehicle speed has reached a level determined by the reference signal, whereby the complete inflation of the air-bag is ensured when a collision occurs without a time delay regardless of changes in temperature.

Abstract: A sensor control circuit which includes a first sensor for detecting an event; a second sensor having identical characteristics with those of the first sensor for detecting the event at the same time; a processing unit having a first processing section for receiving and processing a first sensor signal from the first sensor and a second processing section for receiving and processing a second sensor signal from the second sensor; a first switching unit for switching in response to a first output from the first processing section; a second switching unit for switching in response to a second output from the second processing section; the first and second processing sections being made so as to turn on the first switching unit prior to the second switching unit in response to the first and second sensor signals; and a monitor unit for preventing current conduction to a load if the second switching unit is turned on prior to the first switching unit.

Abstract: A system for controlling a safety device for a vehicle includes first and second switching elements connected to a power source in serial relation to the safety device. The control system further includes a pair of acceleration sensors, a pair of analog processing circuits, and a microcomputer. In accordance with an deceleration signal from the corresponding acceleration sensor, each analog processing circuit outputs a collision decision signal. In accordance with the signals from the acceleration sensors, the microcomputer makes calculations to output two collision decision signals respectively from two output ports thereof. The control system further includes two logic elements. One of the logic elements, when simultaneously receiving any two out of the above four collision decision signals, turns on one of the two switching elements. The other logic element, when simultaneously receiving the other two collision decision signals, turns on the other switching element.