Abstract: A switch device includes a plurality of communication ports; a switch unit configured to relay a frame, which has been transmitted from a function unit and to which information including an ID of a VLAN is added, to another function unit via a communication port; and a duplication unit configured to, when the diagnosis device is connected to another switch device, duplicate the frame to be relayed via a designated communication port among the plurality of communication ports, and generate a duplicate frame for diagnosis that is a frame obtained by adding, to a duplicate frame obtained through the duplication, specific information indicating that the duplicate frame for diagnosis should be transmitted to the diagnosis device. The switch unit outputs the duplicate frame for diagnosis generated by the duplication unit from a communication port corresponding to the other switch device.

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: In the apparatus, a CPU 5 receives through its first and second I/O terminals a pair of voltages proportional to a terminal voltage of an electrolytic capacitor 4 serving as an energy reservoir, and a voltage proportional to an output voltage of a booster circuit 1. When the terminal voltage of the electrolytic capacitor 4 exceeds its breakdown voltage, a transistor 9 conducts, which permits the electrolytic capacitor 4 to discharge, whereby the over-voltage condition of the electrolytic capacitor 4 is resolved.

Abstract: A system for controlling an object such as a vehicle safety device comprises a microcomputer, and reset circuits. The microcomputer judges whether or not an identification data is stored in a specific area of the RAM in order to identify the kind of the resetting method. If the judgment result is "NO", the object is controlled after an early judgment of the control system is effected. In contrast, if the judgment result is "YES", the object is controlled without effecting the early checking.

Abstract: In a control apparatus that activates a preloader device and after a timing delay an air bag device when a vehicle collision is detected, the apparatus has a detector for detecting whether or not a seatbelt is buckled, and a timing signal for activating the air bag device is generated without the timing delay if the seatbelt is not buckled, whereby the air bag device can be activated with a timing appropriate to the condition present at the time.

Abstract: A control system for a vehicle safety device includes a drive circuit. The drive circuit includes a main switching element, and a safety switch which is turned on by an inertia force produced at the time of a collision of the vehicle. The vehicle safety device is activated when the main switching element and said safety switch are both turned on. The control system further includes an acceleration sensing circuit for detecting deceleration of the vehicle, and a microcomputer. The microcomputer judges, based on a deceleration signal from the acceleration sensing circuit, whether or not a collision has occurred, and outputs an ON-instruction signal to the main switching element when the microcomputer judges that the collision has occurred. The microcomputer also judges whether or not the acceleration sensing circuit is subjected to a malfunction, and judges whether the safety switch is in the ON state or the OFF state.

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: A system for controlling the activation of an air bag for a vehicle includes a capacitor connected to a battery via a main electric wire. The supply of electric current from the capacitor to a squib of the air bag is controlled by a first switch. Upon collision of the vehicle, the first switch is closed to allow current to flow to the squib of the air bag. The control system further includes a malfunction alarm device which is connected to the battery via an auxiliary electric wire. The supply of current from the battery to the malfunction alarm device via the auxiliary electric wire is controlled by a second switch. When an electric current path, extending between the battery and the capacitor and including the main electric wire, is interrupted, the second switch is intermittently closed to operate the malfunction alarm device.

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.