| 摘要 |
PROBLEM TO BE SOLVED: To prevent signal amplitudes in a modulation frequency band exceeding the operation range of a subtractor and a modulation circuit from being left in a feedback signal from input side of the wiring, when driving a capacitive load connected by wiring.SOLUTION: A differential signal Diff between a drive waveform signal WCOM and a feedback signal Ref is pulse-modulated, the modulated signal PWM is power-amplified by a digital power amplifier circuit 27, the power amplified modulation signal APWM is smoothed, and the drive signal COM is applied to an actuator 19 composed of a capacitive load connected by wiring 35. In the foregoing process, an inductor L and the actuator 19 are connected by the wiring 35 to form a smoothing filter 28, an inductor output signal SL output from the connection of the inductor L and the wiring 35 is passed through a compensator 29 and an attenuator 30 to obtain a feedback signal Ref to a subtractor 25, thereby allowing the attenuator 30 to attenuate the signal amplitude of a modulation frequency band fin the feedback signal Ref. |
