PROBLEM TO BE SOLVED: To suppress change in frequency characteristics of a filter constituted of a smoothing filter and capacitance of actuators driven while avoiding power consumption of a dummy load.SOLUTION: A capacitive load driving device includes: performing a pulse modulation of a difference signal Diff between a drive waveform signal WCOM and a feedback signal Ref performing a power amplification of the modulated signal PWM by a digital power amplifying circuit 27 smoothing the power amplified modulated signal APWM by a smoothing filter 28 providing two feedback circuits 201, 202 having different frequency characteristics, for example, when a drive signal COM is applied to an actuator 19 comprising a capacitive load such as a piezoelectric element adjusting the frequency characteristics of the feedback circuits by switching the two feedback circuits 201, 202 in accordance with the number of actuators 19 to be driven and suppressing the change in frequency characteristics of the filter constituted of the smoothing filter 29 and capacitance of actuators 19 driven.COPYRIGHT: (C)2012,JPO&INPIT【課題】ダミー負荷による電力消費を回避しながら平滑フィルターと駆動されるアクチュエーターの容量で構成されるフィルターの周波数特性の変化を抑制する。【解決手段】駆動波形信号WCOMと帰還信号Refの差分信号Diffをパルス変調し、その変調信号PWMをデジタル電力増幅回路27で電力増幅し、その電力増幅変調信号APWMを平滑フィルター28で平滑化して、圧電素子などの容量性負荷からなるアクチュエーター19に駆動信号COMを印加する場合に、例えば周波数特性の異なる2つの帰還回路201、202を設け、駆動されるアクチュエーター19の数に応じて2つの帰還回路201、202を切替えることで帰還回路の周波数特性を調整し、平滑フィルター29と駆動されるアクチュエーター19の容量で構成されるフィルターの周波数特性変化を抑制する。【選択図】図6
