Denso Corporation

Nippon Soken, Inc.

Kiyokazu Yoshida

Masahiro Goto

Ryozo Okumura

Fumio Asakura

Takahide Kitahara

Ikuo Hayashi

A controller drives a key interlock solenoid to lock a key so that the key cannot be pulled out of a key cylinder when a shift lever is not at a parking position or while an identification code is being sent to a transponder mounted in the key. Thus, the key cannot be pulled out of the key cylinder during the writing of the identification code in the transponder.

Anti-theft device having excellent identification code overwriting

The power feeding efficiency and the communicable range of an automatic answering system are improved in an automatic answering system using a transponder which performs code communication using amplitude modulation of a carrier with an electromagnetic coupling transponder mounted in a key or the like. In a transceiver for performing the code communication with the transponder via an antenna coil, a circuit for driving the antenna coil in a transceiver based on clock is implemented by a bridge-type complementary circuit of transistors. Thereby, driving current is increased. Meanwhile, a circuit for controlling the driving mode based on a write signal is implemented by a parallel circuit of a transistor to which a power-supply voltage is applied and a resistor. Thereby, a current corresponding to a resistance of the resistor flows through the antenna coil even during the minimum driving when the transistor is turned off, thus improving the power feeding efficiency and the communicable range of the system.

Automatic answering system using transponder

Growing community of inventors

Nishikasugai-gun, Japan

Kiyokazu Yoshida