| 摘要 |
PURPOSE:To diagnose an impact detection system in an air bag system with a simple means as well as to expand the range of an antinoise property in the impact detection system and detecting acceleration. CONSTITUTION:A semiconductor capacitance type detector 1 is used as an impact acceleration detector, and the detection signal is subjected to negative feedback to electrode output terminals 19, 20 of the detector 1 via a servo control circuit 6, and simultaneously it enters an impact discriminator 3, and if it is acceleration of an impact level, an air bag 5 is started via an inflater 4. A diagnostic circuit 9 inputs its diagnostic signal into a negative feedback gate 21 periodically or at a proper time each of impact equivalent electrostatic force generating trigger pulses is impressed in each interval between electrodes 12 and 14 as well as between 12 and 15 via a servo control system. A circuit state in an impact detection system at this time is monitored by the diagnostic circuit 9 which diagnoses whether this impact detection system inclusive of the detectornormally functions or not. |
