Patent ID: 7209338

Claim:
An active vibration insulator, comprising: an electromagnetic actuator for generating vibrating forces by making an electric-current supply variable; means for generating cyclic control signals based on cyclic pulsating signals output from a vibration generating source of a vehicle, the cyclic control signals actively inhibiting a specific part of the vehicle from vibrating; and means for driving the electromagnetic actuator by making the electric-current supply to the electromagnetic actuator variable based on the cyclic control signals, the means comprising: an asymmetric half-bridge circuit comprising a high-side switch connected with a positive-terminal side of the electromagnetic actuator, and a low-side switch connected with a negative-terminal side of the electromagnetic actuator and disposed asymmetrically with respect to the high-side switch; and means for outputting actuating signals, the means outputting a turn-on actuating signal to one of the high-side switch and the low-side switch and outputting a pulse-width-modulated actuating signal to the other one of them based on the cyclic control signals, or outputting a pulse-width-modulated actuating signal to both of the high-side switch and the low-side switch based on the cyclic control signals, when the cyclic control signals are positive; and outputting a turn-off actuating signal to one of the high-side switch and the low-side switch and outputting a pulse-width-modulated actuating signal to the other one of them based on the cyclic control signals when the cyclic control signals are negative.