| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a seat occupant sensing system which can sense certainly the presence of an occupant seated on a vehicle seat and which also allows the reduction of the costs. SOLUTION: This occupant sensing system comprises an antenna electrode installed on each seat, a means 21 to generate a fine electric field around the antenna electrode, an amplitude control circuit 22 to control approx. constant the voltage amplitude of a transmission signal from the electric field generating means, a current sensing circuit 25 to sense the transmission current flowing through the antenna electrode via the amplitude control circuit from the generating means on the basis of the fine electric field, a phase difference sensing circuit 29 to sense the phase difference between the transmission signal given by the generating means and the output signal to the antenna electrode, a control circuit 31 to sense the seating of an occupant on the seat on the basis of the output signals from the current sensing circuit and phase difference sensing circuit, and a power supply circuit 33 which produces single unit of power supply having a single DC voltage from a battery, wherein the single unit of power supply based upon the power supply circuit is used as a system power source for various circuits containing the control circuit.</p> |
