ELECTRONIC KEY SYSTEM AND AUTOBICYCLE USING THE SAME

摘要

To achieve the batteryless of electronic keys used for autobicycles and improve the security. While an electronic key is inserted in a keyhole, a communication circuit (44) is activated. An electromotive force, which occurs in a coil (L2) in accordance with the variation of an electromagnetic field of a frequency (f0) generated by the communication circuit (44), is rectified by a power supply circuit (74) and then supplied to the components of an electronic key side circuit (40) as a power supply. In the electronic key side circuit (40), identification information is read from a storage part (72) and then converted to ternary data by a binary value/ternary value converting circuit (70). The on/off controls of transistors (Tr1,Tr2) are performed in accordance with the bit values of 2-bit data representative of the ternary data, thereby changing the impedances of a coil (L1) in three levels to induce three levels of variation in the electromagnetic field between the coils (L1,L2). The communication circuit (44) detects this variation, and then a ternary value/binary value converting circuit (54) performs a ternary value-to-binary value conversion to acquire the original identification information. An ECU (56) examines the identification information. If the identification information is verified, then the ECU (56) activates an engine (62).